PRINTING MEDIA-OPERATED ACTUATOR ARRANGEMENT.

ACCUMULATOR

An outside gas type accumulator has a mechanism for reducing the pressure difference occurring when liquid confined in a liquid chamber and gas filling the liquid chamber in zero-down state expand thermally, and restrains abnormal deformation of a bellows by reducing the pressure difference between the inside and outside of the bellows. A pressure difference regulation mechanism (21) reduces the pressure difference occurring when liquid confined in the liquid chamber (11) and gas filling the liquid chamber in the zero-down state expand thermally. The regulation mechanism (21) has a movable plate (22) supported by a coil spring (23) on the oil port (4) side of a bellows cap (8). During normal operation, the plate (22) moves together with the cap (8) by being supported by the spring (23), and the plate (22) moves together with the cap (8) and to be brought into contact with a seal (13) in the zero-down state. When the liquid and the filling gas expand thermally, the plate (22) maintains contact ...

AUTOMATIC RELEASE AND CENTERING DEVICE

An automatic release and centering device for a double acting hydraulic cylinder, the device includes a housing, an actuating rod mounted for axial motion within the housing and being connected to the control valve for the hydraulic cylinder, the actuating rod being movable in either direction from a neutral position to an actuated position, a pair of detent members mounted on the rod, each detent member being connected to move in one direction with the rod, a detent assembly positioned to engage and hold a detent member in an actuated position, a spring positioned to bias the detent members and the rod to the neutral position and a pressure actuated release system to release the detent assembly from the detent member.

Electro hydrostatic actuators

An electro hydrostatic actuator comprises a hydraulic pump driven by an electric motor to supply hydraulic fluid to a hydraulic actuator. The pump comprises an inlet and an outlet for the hydraulic fluid and an active flow path arranged therebetween such that, in an active mode of operation when the pump is driven by the electric motor, hydraulic fluid is actively drawn in through the inlet and exhausted out through the outlet. The pump further comprises a bypass flow path arranged to open between the inlet and outlet such that, in a damping mode of operation when the pump is not driven by the electric motor, hydraulic fluid is able to pass through the pump along the bypass flow path between the inlet and outlet.

Improvements in servo motors

... 577,912. Fluid-pressure servomotorcontrol systems. HOBSON (AIRCRAFT & MOTOR) COMPONENTS, Ltd., H. M., and MADDOX, S. V. Jan. 1, 1944, No. 12. [Class 135] In an hydraulic servomotor in which the power device (i.e. piston or rotary vane) is moved to one or other of two end positions under the control of an operating valve actuated by a pressure sensitive device, means under the control of, and operated by, the power device is provided to allow unrestricted pressure fluid to act on the latter after the normal (slow) initial movement in either direction to enable the power device to travel at high speed for a portion of the remainder of its stroke. As applied to a vane-type servomotor 21, Fig. 1, for changing the gear ratio of a blower on an aircraft engine, the operation of the servomotor is controlled by atmospheric pressure acting on a capsule stack 10 whose longitudinal movements are communicated to a piston valve 12. The latter may have one or two lands, and the lands are wider than the ...

PRESSURE MEDIUM ACTUATED SERVOMOTOR SYSTEM

A pressure medium actuated servomotor system is disclosed which includes a piston sliding in a cylinder. The piston limits within the cylinder two chambers, each being connected by a first individual line to a pressurized medium source. A second individual line for each of the chambers connects the chamber to a pressurized medium sink. A control valve is disposed in one of the two connecting lines of each chamber. A restructure is arranged in the second connecting line of each piston chamber. At least a first one of the two control valves is connected to an external control line. According to the invention, the second control valve is operable by pressurized medium and communicates over an internal control line with the piston chamber to which the control valve communicating with the external control line is connected. The advantage is in that the servomotor can be actuated by utilizing only a single line which does not have to be loaded more heavily than each of the two single lines typical ...

Servo motor for positioning a valve as a function of engine load

HYDRAULIC LINK IN A CONTROL SYSTEM

Variable geometry units e.g. stator vane, control device for turbojet engine of aircraft, has by-pass connecting two conduits of supply circuit for ensuring calibrated reverse flow, where by pass is closed by thermostatic valve

La présente invention porte sur un dispositif de commande d'organes à géométrie variable dans un turboréacteur comprenant un actionneur (2) desdits organes, un circuit (1) d'alimentation en fluide d'asservissement de l'actionneur avec une première (5A) et une deuxième (5B) portions de circuit soumises à une pression différentielle pour la commande de l'actionneur (2), un conduit (30) de dérivation de l'actionneur reliant la première et la deuxième portions de circuit pour assurer un débit de fuite calibré. L'actionneur est caractérisé par le fait que le conduit de dérivation est fermé par un clapet thermostatique (31).

NEUTRAL TIME DELAY FLUID CONTROL CIRCUIT

Articulated rod steering gear, usable in particular for the ordering of a reversible engine

FLUID-OPERABLE DEVICE INCLUDING A PISTON NORMALLY-BALANCED BY FLUID PRESSURE ACTING THEREON

SYSTEM AND METHOD FOR PAVING A SURFACE AND REMOTELY CONTROLLING THE FLOW OF PAVING MATERIAL FROM A DUMP TRUCK INTO A HOPPER OF A PAVER

A method for paving wherein the paving operator or a person in the vicinity of the paver remotely controls the flow of paving material from a dump truck into the hopper of the paver.

SYSTEM FOR ACTUATING A CONTROL SURFACE OF AN AIRCRAFT.

Hydraulic cylinder spool valve device

A hydraulic cylinder spool valve device, which extends and retracts a cylinder rod of a hydraulic cylinder, includes: a first spool valve having a first dead band and a first opening characteristic; a second spool valve having a second dead band and a second opening characteristic; and a controller performing communication with the hydraulic cylinder by using the first spool valve and positioning the second spool of the second spool valve within the second dead band and performing communication with the hydraulic cylinder by using the second spool valve and positioning the first spool of the first spool valve within the first dead band, and adjusting a characteristic of a switching dead band between the first opening characteristic and the second opening characteristic.

CONTROL DEVICE Of BODY HAS GEOMETRY VARIABLE IN a TURBOJET.

Sophisticated safety device ordering the admission of a driving fluid after simultaneous actuation of two manually actuated separate valves

Improvements with the driving devices with fluid usable in various types of machines, and in particular in the folding and grooving machines

Process and control device for hydraulic systems

Improvements in or relating to hydraulic or pneumatic actuator systems for rams incorporating ram-locking means

... 1,045,881. Fluid pressure apparatus. PLESSEY CO. Ltd. March 20, 1963 [Dec. 21, 1961], No. 45941/61. Heading F1P. [Also in Division B7] In an hydraulic or pneumatic actuator system especially for reversing the thrust of aircraft engines, a double-acting main ram 1 for opening the thrust reverse doors is locked in its extended position, in which the doors are open, by a pivoted lever 30 movable to its fully released position by an actuator rod 28 before a control valve 9 operates to cause the main ram 1 to move. In the fully locked position a selector valve 40 is positioned with its piston valve 41 moved to the right and the remainder of the system is positioned as shown. In this position pressure fluid is supplied through a duct 8, a central chamber 16 in the control valve 9 and a duct 19 leading to the ram cylinder 3 to act upon the side 7 of the ram piston 2, the fluid on the other side thereof being vented to atmosphere through a port 23. A branch duct 48 leading from the duct 8 supplies ...

PRESSURE MEDIUM ACTUATED SERVOMOTOR SYSTEM

Device of operation of an oil and air equipment

Hydraulic control device for hydraulic drive, has pressure relief valves switched parallel to each other, where fluidic connection of pressure relief valve with medium-sink is enhanced based on driving direction of actuator

The device (1) has an actuator (2) attached to a throttle valve (8) for controlling pressure medium flow rate of a hydro pump (4). A pressure tap (20) is arranged in an inlet direction at the throttle valve. First and second pressure relief valves (38, 40) derivate pressure medium of the tap to a pressure medium-sink (T). The pressure relief valves are switched parallel to each other and fluidically connected with the tap. A fluidic connection of the first pressure relief valve with the medium-sink is enhanced based on driving direction of the actuator.

Hydraulic transmission

Process and control device of one or several hydraulic systems

Controller forselective

Electro hydrostatic actuator

An electro hydrostatic actuator comprising a hydraulic pump driven by an electric motor to supply hydraulic fluid to a hydraulic actuator, the pump comprising an inlet and an outlet for the hydraulic fluid and an active flow path configured therebetween such that, in an active mode of operation when the pump is driven by the electric motor, hydraulic fluid is actively drawn in through the inlet and exhausted out through the outlet. The pump further comprises a bypass flow path configured to open between the inlet and outlet such that, in a damping mode of operation when the pump is not driven by the electric motor, hydraulic fluid is able to pass through the pump along the bypass flow path between the inlet and outlet. The hydraulic pump is a rotary piston pump comprising a pump barrel driven to rotate by a motor shaft.

ACCUMULATOR

To restrain abnormal deformation of a bellows due to a pressure difference between the inside and outside thereof, an outside gas type accumulator includes a pressure difference regulation mechanism (21) having a movable plate (22) supported by a coil spring (23) on the oil port (4) side of a bellows cap (8), the plate (22) moves together with the cap (8) in a state of being supported by the spring (23), during normal operation, the plate (22) moves together with the cap (8) to be brought into contact with a seal (13) at zero-down time, and the plate (22) keeps contact with the seal (13) and the cap (8) moves to a position where liquid pressure and gas pressure balances while compressing the spring (23) when the liquid and the charged gas expand thermally.

Bucket positioner kickout slave cylinder

A combination slave cylinder and relief valve for controlling release of a valve lever from a detented position. The valve is operated by pressurized fluid and is arranged to relieve the fluid pressure at a preselected value above that required for release of the lever.

Actuator control system

A control system for controlling the operation of a valve actuator. The system includes a control valve for conveying operating fluid to the actuator in response to an actuator control signal. A single conduit operably connected to the actuator control valve both supplies operating fluid to the control valve and conveys an actuator control signal to the control valve.

ACCUMULATOR

An outside gas type accumulator has a mechanism for reducing the pressure difference occurring when liquid confined in a liquid chamber and gas filling the liquid chamber in zero-down state expand thermally, and restrains abnormal deformation of a bellows by reducing the pressure difference between the inside and outside of the bellows. A pressure difference regulation mechanism (21) reduces the pressure difference occurring when liquid confined in the liquid chamber (11) and gas filling the liquid chamber in the zero-down state expand thermally. The regulation mechanism (21) has a movable plate (22) supported by a coil spring (23) on the oil port (4) side of a bellows cap (8). During normal operation, the plate (22) moves together with the cap (8) by being supported by the spring (23), and the plate (22) moves together with the cap (8) and to be brought into contact with a seal (13) in the zero-down state. When the liquid and the filling gas expand thermally, the plate (22) maintains contact ...

Halte- und Loesseeinrichtung fuer hydraulische Wegeventile

Wegeventil mit mehreren Betriebszuständen bezüglich einer Rastung

Die Erfindung betrifft ein Wegeventil (30) mit einem ersten Ventilschieber (40), der mehrere Stellungen (41; 42; 43; 44) hat, wobei eine Rastvorrichtung (60) vorgesehen ist, welche mittels wenigstens einer Magnetspule (64) wahlweise aktivierbar oder deaktivierbar ist.Erfindungsgemäß ist im Bereich der wenigstens einen Magnetspule (64) eine Untersteuervorrichtung (70) angeordnet ist, welche an die wenigstens eine Magnetspule (64) angeschlossen ist, so dass mittels der Untersteuervorrichtung ein Strom durch die wenigstens eine Magnetspule (64) einstellbar ist, wobei eine Stellungsermittlungsvorrichtung (72) unmittelbar an die Untersteuervorrichtung (70) angeschlossen ist, wobei die Untersteuervorrichtung (70) wenigstens ein Auswahlmittel (73) umfasst, mittels dessen wenigstens zwei Betriebszustände der Untersteuervorrichtung (70) auswählbar sind, wobei in den verschiedenen Betriebszuständen bestimmten Stellungen des ersten Ventilschiebers (40) jeweils unterschiedliche Ströme in der wenigstens ...

Hydraulic latching apparatus for a control system

A system for hydraulically detecting the seizure of a control valve in a hydraulic servo valve system wherein a hydraulic signal generated responsive to the control valve seizure is utilized to translate a bypass valve from its operational position to its bypass position and simultaneously to provide a hydraulic signal for maintaining the bypass valve in its bypassed position.

ELECTRO HYDROSTATIC ACTUATOR

An electro hydrostatic actuator comprising a hydraulic pump driven by an electric motor to supply hydraulic fluid to a hydraulic actuator, the pump comprising an inlet and an outlet for the hydraulic fluid and an active flow path configured therebetween such that, in an active mode of operation when the pump is driven by the electric motor, hydraulic fluid is actively drawn in through the inlet and exhausted out through the outlet. The pump further comprises a bypass flow path configured to open between the inlet and outlet such that, in a damping mode of operation when the pump is not driven by the electric motor, hydraulic fluid is able to pass through the pump along the bypass flow path between the inlet and outlet. The hydraulic pump is a rotary piston pump comprising a pump barrel driven to rotate by a motor shaft.

Sicherheitsventilanordnung

Die Erfindung betrifft eine Sicherheitsventilanordnung (100). Die Sicherheitsventilanordnung (100) weist eine Wechselventileinrichtung (210) und eine Wegeventileinrichtung (230) auf. Zudem weist die Wegeventileinrichtung (230) einen Primärkanal (231), einen Sekundärkanal (232), eine zwischen dem Primärkanal (231) und dem Sekundärkanal (232) angeordnete Überströmöffnung (233), eine Rückstellkammer (234), und ein zwischen der Überströmöffnung (233) und der Rückstellkammer (234) angeordnetes Stellelement (235) auf. Ferner ist das Stellelement (235) zwischen einer Schließstellung, in welcher ein Endabschnitt des Stellelements (235) die Überströmöffnung (233) verschließt, und einer Offenstellung, in welcher der Primärkanal (231) und der Sekundärkanal (232) über die Überströmöffnung (233) fluidleitend verbunden sind, bewegbar. Des Weiteren ist der Primärkanal (231) mit einem Primäreingang (211) der Wechselventileinrichtung (210) fluidleitend verbunden. Zudem ist der Sekundärkanal (232) mit einem ...

Hydraulisches Wegeventil

Ein hydraulisches Wegeventil (10) zum Ansteuern eines hydraulischen Verbrauchers (30), mit einem Gehäuse (12) mit einem Pumpenanschluss (P) zur Verbindung mit einer Druckversorgung (40), einem Tankanschluss (T) zur Verbindung mit einem Hydraulikölreservoir (42) und einem ersten und einem zweiten Arbeitsanschluss (A, B) zur Verbindung mit dem hydraulischen Verbraucher (30) und einem ersten und einem zweiten Ventilschieber (141, 142), die in dem Gehäuse (12) in einer Verschieberichtung (V) linearbeweglich gehalten sind.

Stromventil mit Vorsteuerung und Druckkompensation

FLUID PRESSURE ACTUATED SERVO MOTOR DEVICE

Actuator control system

A control system for controlling the operation of a valve actuator. The system includes a control valve for conveying operating fluid to the actuator in response to an actuator control signal. A single conduit operably connected to the actuator control valve both supplies operating fluid to the control valve and conveys an actuator control signal to the control valve.

HYDRAULIC CYLINDER SPOOL VALVE DEVICE

A hydraulic cylinder spool valve device, which extends and retracts a cylinder rod of a hydraulic cylinder, includes: a first spool valve having a first dead band and a first opening characteristic; a second spool valve having a second dead band and a second opening characteristic; and a controller performing communication with the hydraulic cylinder by using the first spool valve and positioning the second spool of the second spool valve within the second dead band and performing communication with the hydraulic cylinder by using the second spool valve and positioning the first spool of the first spool valve within the first dead band, and adjusting a characteristic of a switching dead band between the first opening characteristic and the second opening characteristic.

Servomotor

Fluidbetaetigte Einrichtung

Hydraulisches Bindeglied in einem Steuersystem

Slide valve device for hydraulic cylinder

Valve assembly for plural motor operation

Stromventil mit Vorsteuerung und Druckkompensation

atuador eletro-hidrostático, e, método para controlar e amortecer um atuador hidráulico

Steuerung fuer eine Servo-Vorrichtung

Electro hydrostatic actuators

An electro hydrostatic actuator (EHA) comprises a hydraulic pump and an electric motor driving the hydraulic pump. The hydraulic pump comprises an inlet and an outlet for hydraulic fluid and an active fluid flow path arranged therebetween such that, in an active mode of operation when the pump is driven by the electric motor, hydraulic fluid is actively drawn in through the inlet and exhausted out through the outlet. The hydraulic pump further comprises a bypass flow path arranged between the pump inlet and outlet, such that, in a damping mode of operation, hydraulic fluid is able to freely flow between the inlet and outlet in either direction.

Pressure medium actuated servo-motor system

The servo-motor system is provided with an internal control line which communicates one control valve with a cylinder chamber which is connected to a control valve connected with an external control line. The internal control line permits the second valve to be actuated via the externally controlled control valve.

ELECTRO HYDROSTATIC ACTUATORS

An electro hydrostatic actuator (EHA) comprises a hydraulic pump and an electric motor driving the hydraulic pump. The hydraulic pump comprises an inlet and an outlet for hydraulic fluid and an active fluid flow path arranged therebetween such that, in an active mode of operation when the pump is driven by the electric motor, hydraulic fluid is actively drawn in through the inlet and exhausted out through the outlet. The hydraulic pump further comprises a bypass flow path arranged between the pump inlet and outlet, such that, in a damping mode of operation, hydraulic fluid is able to freely flow between the inlet and outlet in either direction.

System for actuating a control surface of an aircraft

An actuating system comprising a hydraulic actuator provided with a cylindrical cavity containing a piston configured to slide within the cylindrical cavity and a rod. The piston separates the cylindrical cavity into a first actuating chamber and a second actuating chamber. A first servo valve comprises a sheath including a first slider configured to slide within a cavity of the sheath on the basis of command signals from a command system. The cavity of the sheath comprises a first command chamber and a second command chamber on either side of the first slider. The first actuating chamber is fluidically connected to the first command chamber, and the second actuating chamber is fluidically connected to the second command chamber.

Flow control valve with pilot operation and pressure compensation

A pilot-actuated, pressure-compensated flow and directional control valve assembly (11) is provided in which a main valve spool (95) is positioned in response to a pressure differential between a pilot chamber (119) and a reaction chamber (117). Flow of fluid from an inlet port (29) is controlled by means of a pilot valve assembly (97), into the pilot chamber (119), while fluid flows out of the pilot chamber (119) through a fixed orifice (67) to a pump load sense port (61). The main valve spool (95) acts as an inlet compensator. If the pressure at a load L is above inlet pressure, the main valve spool (95) acts as an inlet check, preventing reverse flow. If there is a higher load pressure at another load circuit in the system, such as a steering valve S, there will be an increase in pressure in the reaction chamber (117), thus closing off the main spool (95), reducing the flow from the inlet port (29) to the work port (47), and giving more priority to the steering valve S. If a priority ...

Flow control valve with pilot operation and pressure compensation

AUTOMATIC RELEASE AND CENTERING DEVICE

Hydraulic directional control valve

A hydraulic directional control valve for activating a hydraulic load, comprising a housing with a pump connection for connecting to a pressure source, a tank connection for connecting to a hydraulic fluid reservoir and a first and second working connection for connecting to the hydraulic load, and a first and a second valve slide, which are held in the housing so as to be linearly movable in a displacement direction.

ELECTRO HYDROSTATIC ACTUATORS

An electro hydrostatic actuator comprises a hydraulic pump driven by an electric motor to supply hydraulic fluid to a hydraulic actuator. The pump comprises an inlet and an outlet for the hydraulic fluid and an active flow path arranged therebetween such that, in an active mode of operation when the pump is driven by the electric motor, hydraulic fluid is actively drawn in through the inlet and exhausted out through the outlet. The pump further comprises a bypass flow path arranged to open between the inlet and outlet such that, in a damping mode of operation when the pump is not driven by the electric motor, hydraulic fluid is able to pass through the pump along the bypass flow path between the inlet and outlet.

ACCUMULATOR

PROBLEM TO BE SOLVED: To provide an external gas type accumulator capable of reducing a pressure difference between the inside and the outside of a bellows so as to restrict the abnormal deformation of the bellows by comprising a mechanism for reducing a pressure difference generated when liquid sealed in a liquid chamber or sealed gas is expanded by heat when so-called zero-down is caused. SOLUTION: This accumulator has a pressure difference adjusting mechanism 21 for reducing a pressure difference generated when liquid sealed in a liquid chamber 11 or sealed gas is expanded by heat when so-called zero-down is caused. The adjusting mechanism 21 has a movable plate 22 supported by a coil spring 23 at the oil port 4 side of a bellows cap 8. In a normal operation, the plate 22 is moved together with the cap 8 in a state of being supported by the spring 23, and when the so-called zero-down is caused, the plate 22 is moved together with the cap 8 and brought in contact with a seal 13, and when ...

HYDRAULIC DIRECTIONAL CONTROL VALVE

A hydraulic directional control valve for activating a hydraulic load, comprising a housing with a pump connection for connecting to a pressure source, a tank connection for connecting to a hydraulic fluid reservoir and a first and second working connection for connecting to the hydraulic load, and a first and a second valve slide, which are held in the housing so as to be linearly movable in a displacement direction. 1. A hydraulic directional control valve for activating a hydraulic load , comprising:a housing having a pump connection for connecting to a pressure source, a tank connection for connecting to a hydraulic reservoir, and a first and a second working connection for connecting to the hydraulic load;a first and a second valve slide, slidably received by the housing, the valve slides being movable linearly in a displacement direction in the housing in order to activate the pump connection, the tank connection and the working connection via control edges arranged on the valve slides; andan actuating member operatively connected with the first and the second valve slides in order to press the valve slide in the displacement direction relative to the housing.2. The hydraulic directional control valve of claim 1 , wherein:the first valve slide comprises two first control edges for activating the first working connection, and the second valve slide comprises two second control edges for activating the second working connection.3. The hydraulic directional control valve of claim 1 , wherein:the actuating member has a control cam arrangement for acting upon the valve slides.4. The hydraulic directional control valve of claim 3 , wherein:the valve slides are jointly displaceable by the control cam arrangement relative to the housing, and the position of the valve slides relative to one another in the displacement direction is adjustable.5. The hydraulic directional control valve of claim 3 , wherein:the control cam arrangement has a first and a second cam contour ...

HYDRAULIC LINK IN A CONTROL SYSTEM

NEUTRAL TIME-DELAY FLUID CONTROL CIRCUIT

Flow control valve with pilot operation and pressure compensation

A pilot-actuated, pressure-compensated flow and directional control valve assembly (11) is provided in which a main valve spool (95) is positioned in response to a pressure differential between a pilot chamber (119) and a reaction chamber (117). Flow of fluid from an inlet port (29) is controlled by means of a pilot valve assembly (97), into the pilot chamber (119), while fluid flows out of the pilot chamber (119) through a fixed orifice (67) to a pump load sense port (61). The main valve spool (95) acts as an inlet compensator. If the pressure at a load L is above inlet pressure, the main valve spool (95) acts as an inlet check, preventing reverse flow. If there is a higher load pressure at another load circuit in the system, such as a steering valve S, there will be an increase in pressure in the reaction chamber (117), thus closing off the main spool (95), reducing the flow from the inlet port (29) to the work port (47), and giving more priority to the steering valve S. If a priority ...

Accumulator

An outside gas type accumulator has a mechanism for reducing the pressure difference occurring when liquid confined in a liquid chamber and gas filling the liquid chamber in zero-down state expand thermally, and restrains abnormal deformation of a bellows by reducing the pressure difference between the inside and outside of the bellows. A pressure difference regulation mechanism (21) reduces the pressure difference occurring when liquid confined in the liquid chamber (11) and gas filling the liquid chamber in the zero-down state expand thermally. The regulation mechanism (21) has a movable plate (22) supported by a coil spring (23) on the oil port (4) side of a bellows cap (8). During normal operation, the plate (22) moves together with the cap (8) by being supported by the spring (23), and the plate (22) moves together with the cap (8) and to be brought into contact with a seal (13) in the zero-down state. When the liquid and the filling gas expand thermally, the plate (22) maintains contact ...

ENERGY CONSERVING DIRECTIONAL VALVE-CYLINDER COMBINATION

PILOT OPERATION TYPE PRESSURE COMPENSATION TYPE FLOW CONTROL VALVE

PURPOSE: To provide a pilot-actuated and pressure-compensated control valve having simple structure, a low cost, and a load sense prior function. CONSTITUTION: In a pilot-actuated and pressure-compensated flow and direction control valve 11, a main valve spool 95 is positioned in accordance with a pressure difference between plot and reaction chambers 119 and 117. The flow of fluid entering from an inlet port 29 to the chamber 119 is controlled by a pilot valve 97, while the fluid passes through a fixed orifice 67 from the chamber 119 to flow into a pump load sensible port 61. When load L pressure is higher than inlet pressure, the spool 95 is actuated as an inlet check valve, to prevent a back flow. When the load pressure of another load circuit in a device, e.g. of a steering valve S is higher, the pressure in the chamber 117 is increased, consequently the spool 95 is closed by this pressure increase to reduce the flow from the port 29 to an operation port 47, thereby giving priority ...

Fluid pressure actuated servo motor device

Hydraulic system

Hydraulic latching apparatus for a control system

A system for hydraulically detecting the seizure of a control valve in a hydraulic servo valve system wherein a hydraulic signal generated responsive to the control valve seizure is utilized to translate a bypass valve from its operational position to its bypass position and simultaneously to provide a hydraulic signal for maintaining the bypass valve in its bypassed position.

Fluid pressure actuated servo motor device

The servo-motor system is provided with an internal control line which communicates one control valve with a cylinder chamber which is connected to a control valve connected with an external control line. The internal control line permits the second valve to be actuated via the externally controlled control valve.

Accumulator

To restrain abnormal deformation of a bellows due to a pressure difference between the inside and outside thereof, an outside gas type accumulator includes a pressure difference regulation mechanism (21) having a movable plate (22) supported by a coil spring (23) on the oil port (4) side of a bellows cap (8), the plate (22) moves together with the cap (8) in a state of being supported by the spring (23), during normal operation, the plate (22) moves together with the cap (8) to be brought into contact with a seal (13) at zero-down time, and the plate (22) keeps contact with the seal (13) and the cap (8) moves to a position where liquid pressure and gas pressure balances while compressing the spring (23) when the liquid and the charged gas expand thermally.

ACCUMULATOR

SERVO MOTOR DEVICE OPERATED BY PRESSURE MEDIUM

Accumulator

System and method for paving a surface and remotely controlling the flow of paving material from a dump truck into a hopper of a paver

A method for paving wherein the paving operator or a person in the vicinity of the paver remotely controls the flow of paving material from a dump truck into the hopper of the paver.

Electro-hydraulic mixed-control direct-acting actuator

ENERGY CONSERVING DIRECTIONAL VALVE-CYLINDER COMBINATION

This invention relates to directional control valves designed to conserve fluid energy when serving power cylinders, and more particularly to an energy conserving TANDEM DIRECTIONAL VALVE-CYLINDER COMBINATION utilizing a solenoid valve of simple SPRINGLESS three component design to operate a specially designed power cylinder of differential diameter piston allowing the pressurized fluid to energize the piston of smaller area to do work and to return this piston to the original position by the exhaust of the same working fluid when work is completed, acting over the larger piston area in tandem action with pressurized working fluid passing through the passages of the directional control valve allowing for energy conservation with resultant savings to the user of such unit in automation, instrumentation and miniaturization fields.

Pressure medium actuated servo-motor system

The servo-motor system is provided with an internal control line which communicates one control valve with a cylinder chamber which is connected to a control valve connected with an external control line. The internal control line permits the second valve to be actuated via the externally controlled control valve.

ACTUATOR SYSTEM FOR A FLY-BY-WIRE AIRCRAFT

An actuator system for an aircraft includes an actuator, and a control valve system operatively connected to the actuator. The control valve system includes a first direct drive valve (DDV) mechanically connected to a second DDV. A backup valve system is operatively connected to the actuator. The backup valve system includes one of an electro-hydraulic servovalve (EHSV) and a DDV.

MAINTAINING METHOD FOR EXPANSION AND CONTRACTION OF HYDRAULIC CYLINDER AND ITS HYDRAULIC CIRCUIT

PURPOSE: To prevent the temperature rise of working oil previously by supplying the hydraulic cylinder with working oil from a pump before a driving motor and the pump are driven. CONSTITUTION: In a first circuit, working oil in a first tank 1a is not supplied into an expansion cylinder 6 when working oil in the first tank 1a is supplied to the driving motor 4 and the supply of the oil is stopped. The opening area of the spool of a second-direction control valve 3b is opened completely before the second pump 2b is driven by the driving motor 4, and working oil in a second tank 1b is not throttled and supplied into an oil chamber 63 at the push side of the expansion cylinder 6, thus preventing the temperature rise of working oil. COPYRIGHT: (C)1983,JPO&Japio ...

Flow control valve with pilot operation and pressure compensation

A pilot-actuated, pressure-compensated flow and directional control valve assembly (11) is provided in which a main valve spool (95) is positioned in response to a pressure differential between a pilot chamber (119) and a reaction chamber (117). Flow of fluid from an inlet port (29) is controlled by means of a pilot valve assembly (97), into the pilot chamber (119), while fluid flows out of the pilot chamber (119) through a fixed orifice (67) to a pump load sense port (61). The main valve spool (95) acts as an inlet compensator. If the pressure at a load L is above inlet pressure, the main valve spool (95) acts as an inlet check, preventing reverse flow. If there is a higher load pressure at another load circuit in the system, such as a steering valve S, there will be an increase in pressure in the reaction chamber (117), thus closing off the main spool (95), reducing the flow from the inlet port (29) to the work port (47), and giving more priority to the steering valve S. If a priority ...

Bucket positioner kickout slave cylinder

A combination slave cylinder and relief valve for controlling release of a valve lever from a detented position. The valve is operated by pressurized fluid and is arranged to relieve the fluid pressure at a preselected value above that required for release of the lever.

Work machine and control method for work machines

In a work machine, a control unit controls a pilot control valve for controlling the opening area of a first direction switch valve in executing the combined operation to be less than or equal to that in executing a single operation. The combined operation represents an operation of simultaneously operating first and second actuators. The single operation represents an operation of operating only the first actuator. Further, the control unit determines the opening area of the first direction switch valve in the combined operation based on a hydraulic pressure detected by a hydraulic pressure detector unit.

Brake system and method

A hydraulic system for an aircraft includes a brake operation device, a pressure supply, a reservoir, a shut-off valve, and a wheel brake. The shut-off valve is in fluid communication with and is disposed between the pressure supply and the brake valve. The shut-off valve can include a poppet, a first valve seat and a second valve seat. Movement of the poppet is controlled by operation of the brake operation device. The poppet is movable between a first position where the poppet acts against the first valve seat and a second position where the poppet acts against the second valve seat. In the first position, fluid flow is blocked between the pressure supply and the brake valve through the shut-off valve. In the second position, fluid flow is allowed between the pressure supply and the brake valve through the shut-off valve. The wheel brake is in fluid communication with and downstream from the shut-off valve.

Hydraulic system having dual tilt blade control

A hydraulic system for a machine is disclosed. The hydraulic system may have a tank configured to hold a supply of fluid, a pump configured to draw fluid from the tank and pressurize the fluid, a first cylinder operatively connected between a first side of a work tool and an undercarriage of the machine, and a second cylinder operatively connected between a second side of the work tool and the undercarriage of the machine. The hydraulic system may also have a first electro-hydraulic valve associated with the first cylinder and configured to selectively regulate a flow of pressurized fluid to the first cylinder independently of the second cylinder, and a second electro-hydraulic valve associated with the second cylinder and configured to selectively regulate a flow of pressurized fluid to the second cylinder independently of the first cylinder.

Split valve pump controlled hydraulic system

A hydraulic system that includes a controller controlling multiple hydraulic pumps to power multiple hydraulic functions. Any ratio of flow can be directed from each of the pumps to each of the functions, including having a pump dedicated to each function, or having one pump dedicated to one function and another pump supplying multiple functions including the one function. The controller can receive machine feedback and failure data indicating regions of the system with functional disruptions, and can direct flow from the pumps to the functions along routes that avoid the functional disruptions. The system can include operator input devices that provide operator inputs to the controller for controlling the system. The system can operate the hydraulic system in different modes, including modes to improve fuel efficiency and to improve productivity. The system can include a mode switch for operator selection of a desired mode.

Electro-hydraulic sensor fail safe

A fail-safe system and method for an electro-hydraulic system. The system includes a controller, sensor, directional control valve, interlock, hydraulic valve and movement actuator. The directional control valve moves when the controller is moved. The interlock is hydraulically coupled to the directional control valve; and is in active position when the directional control valve is moved, and in shutoff position when the directional control valve is not moved. The hydraulic valve has an input side coupled to a flow source and an output side coupled to a hydraulic function. The movement actuator moves the hydraulic valve to a desired position as directed by the controller when the interlock is in the active position, and does not move the hydraulic valve when the interlock is in the shutoff position. The sensor detects movement of the controller and sends a control signal to the first valve actuator.

Closed-loop hydraulic system having energy recovery

A hydraulic system is disclosed. The hydraulic system may have a pump with variable-displacement, a first linear actuator, and a second linear actuator coupled to the first linear actuator to operate in tandem. The first and second linear actuators may be connected to the pump in closed-loop manner, and each of the first and second linear actuators may have a first chamber and a second chamber separated by a piston. The hydraulic system may also have an accumulator in fluid communication with the second chamber of only the second linear actuator.

Electronic load drop protection for hydraulic fluid system

A method of controlling a valve includes detecting a supply pressure at a fluid source and detecting a first port pressure at a first side of a piston. A controller actuates the valve from a closed position to a first open position when the supply pressure is in excess of the first port pressure. Thereafter, the controller actuates the valve to the closed position when the supply pressure is less than the first port pressure.

Digital Control Method for a Hydraulic ON/OFF Valve

The disclosure relates to a digital control method for a hydraulic ON/OFF valve. The ON/OFF valve is controlled by a digital control signal. The digital control signal has a number of successive cycles. Each cycle of the number of successive cycles has a pulse lasting a variable pulse period and a pause lasting a variable pause period. The pause period (t p ) of each cycle is set taking into account the time when the ON/OFF valve reaches the OFF state after the pulse of the cycle.

Working machine

A working machine rendered to change in setting a maximum value of an absorption torque of hydraulic pump to a rather high value when the working machine is in a specified state, solves problems that, when an operation lever is being operated in an intermediate position of a lever stroke, there occurs a swinging in a machine body due to change-over of a maximum absorption torque setting value so that the operation lever is relatively moved with respect to the machine body to exert an influence on operability and the machine body acting violently. When the maximum absorption torque setting value is E2 position which is good fuel efficiency, upon detection of a full operation of either one or both of the travelling operation member and the boom operation member, controlling to automatically switch to E1 position of a maximum absorption torque larger than that of E2 position is performed.

Systems and methods for energy storage and recovery using gas expansion and compression

In various embodiments, energy-storage systems are based upon an open-air arrangement in which pressurized gas is expanded in small batches from a high pressure of, e.g., several hundred atmospheres to atmospheric pressure. The systems may be sized and operated at a rate that allows for near isothermal expansion and compression of the gas.

Forming liquid sprays in compressed-gas energy storage systems for effective heat exchange

In various embodiments, efficiency of energy storage and recovery systems compressing and expanding gas is improved via heat exchange between the gas and a heat-transfer fluid.

Fail-safe actuation system

Disclosed is a fail-safe fluidic actuation system ( 1 ) having a safety position, comprising a control element ( 2 ) having at least one first and one second chamber ( 3, 4 ); having a working circuit ( 5 ) with a motor/pump device ( 6 ), wherein the control element can be actuated by means of the working circuit at least in the operational state. Furthermore, the actuating system comprises a discharge valve ( 9 ) which, in a failure state, is placed into a pass-through position in order to discharge fluid from the second chamber, and the safety circuit is designed such that, in the operational state, an inflow decoupled from the store can be generated into the control element by means of the working circuit with the motor/pump device, wherein by means of the safety circuit, in a failure state, an inflow fully decoupled from the working circuit with the motor/pump device is provided into the first chamber by means of the store, wherein the control element has three chambers, and wherein the safety circuit is designed such that, in the operational state, an inflow decoupled from the store can be generated into the third chamber ( 15 ) by means of the working circuit with the motor/pump device.

Synchronized lifting and lowering apparatus

A synchronous lifting or lowering system with hydraulic cylinders controlled by parallel-connected lift valves having two fluid passages. Hydraulic fluid for extending or retracting the actuators is delivered by a hydraulic supply system alternating between the two passages. Each time the supply circuit alternates passages, a fixed volume of hydraulic fluid is transferred during lifting or received during lowering by the respective lift or lowering valves to or from the cylinders causing the rods to lift or lower a proportionate amount. All of the rods extend during advancement or retract during lowering by approximately the same increment each time the supply circuit alternates passages. Because the rods all extend or retract the same increment each cycle, the load is lifted or lowered evenly and the need for height sensors or transducers is eliminated.

Hydraulic system for construction machinery

A hydraulic system for a construction machine is disclosed, which can prevent off-course travel of the machine when a combined operation of a traveling device and a working device such as a boom is performed. The hydraulic system for a construction machine includes first and second hydraulic pumps, left and right traveling operation levers and actuator operation levers for first and second working devices, a left traveling motor connected to a discharge flow path of the first hydraulic pump and an actuator for the first working device, a right traveling motor connected to a discharge flow path of the second hydraulic pump and an actuator for the second working device, a first pressure compensated valve installed on one side of an upper stream and a downstream of the first control valve, a second pressure compensated valve installed on one side of an upper stream and a downstream of the second control valve, a third pressure compensated valve, a fourth pressure compensated valve installed on one side of an upper stream and a downstream of the fourth control valve, a first orifice connected to the first pressure compensated valve of the first control valve, a first load sensing line connected to the fourth pressure compensated valve of the fourth control valve, and a hydraulic tank, a second orifice connected to the second pressure compensated valve of the second control valve, a second load sensing line connected to the third pressure compensated valve of the third control valve, and the hydraulic tank, a confluence valve installed in a confluence flow path of the first and second hydraulic pumps, a traveling communication valve installed in a flow path connecting the downstream of the left traveling first pressure compensated valve to the downstream of the right traveling third pressure compensated valve, and a controller controlling communication of the traveling communication valve when a combined operation for simultaneously operating the traveling device and the ...

Work machine

To provide a work machine that makes it possible to drive actuators faster and more accurately by supplying flows to the actuators accurately at target rates without depending on load variations in a case where the machine body is controlled automatically by command inputs of a controller, while high operability is ensured for manual operation by an operator. In a case where a machine control function is cancelled via a machine control switch, a controller cancels limitation of the flow rate of a hydraulic fluid supplied to a plurality of directional control valves, the limitation being performed by the auxiliary flow rate control devices, and in a case where the machine control function is selected via the machine control switch, the controller causes the auxiliary flow rate control devices to limit the flow rate of the hydraulic fluid supplied to the plurality of directional control valves.

METHODS AND APPARATUS TO ENABLE BOOM BOUNCE REDUCTION AND PREVENT UN-COMMANDED MOTION IN HYDRAULIC SYSTEMS

A hydraulic system () and method for reducing boom dynamics of a boom (), while providing counter-balance valve protection, includes a hydraulic actuator (), first and second counter-balance valves (), first and second independent control valves (), and first and second blocking valves (). The actuator includes first and second corresponding chambers. In a first mode, the second counter-balance valve is opened by the first control valve, and the first counter-balance valve is opened by the second control valve. In a second mode, at least one of the counter-balance valves is closed. A meter-out control valve () may be operated in a flow control mode, and/or a meter-in control valve () may be operated in a pressure control mode. Boom dynamics reduction may occur while the boom is in motion (e.g., about a worksite). By opening the counter-balance valves, sensors at the control valves may be used to characterize external loads. The control valves may respond to the external loads and at least partially cancel unwanted boom dynamics. The system may further detecting faults in actuators with counter-balance valves and prevent any single point fault from causing a boom falling event and/or mitigate such faults. 142.-. (canceled)43. A method of controlling a hydraulic actuator hydraulically coupled to a pair of counter-balance valves , the method comprising:providing the hydraulic actuator, the hydraulic actuator including a pair of chambers hydraulically coupled to the pair of counter-balance valves;providing a pair of control valves hydraulically coupled to the pair of counter-balance valves;operating one of the pair of control valves in a pressure control mode;operating the other of the pair of control valves in a flow control mode;transferring hydraulic fluid flow with the pair of control valves to/from the hydraulic actuator via the pair of counter-balance valves; andsending a first control signal to one of the pair of control valves and a second control signal to the ...

Aircraft Landing Gear Steering Systems and Methods with Enhanced Shimmy Protection

An example aircraft includes (i) a landing gear having a chassis, an axle, and wheels mounted to ends of the axle; (ii) a hydraulic actuator including a cylinder, a first piston coupled to the chassis, and a second piston coupled to the axle; and (iii) a directional control valve including: inlet ports configured to be fluidly coupled to a source of pressurized fluid, tank ports configured to be fluidly coupled to a tank, and workports configured to be fluidly coupled to the hydraulic actuator. 1. A hydraulic system comprising:a hydraulic actuator comprising: (i) a cylinder, (ii) a partition disposed in the cylinder and configured to divide the cylinder into a first partition and a second partition, (iii) a first piston slidably accommodated in the first partition and having a piston head and a rod extending from the piston head along a longitudinal axis of the cylinder, wherein the rod is configured to be coupled to a chassis of a landing gear of an aircraft, and wherein the piston head divides the first partition into a first chamber and a second chamber, and (iv) a second piston slidably accommodated in the second partition and having a respective piston head and a respective rod extending from the respective piston head along the longitudinal axis of the cylinder, wherein the respective rod is configured to be coupled to an axle of the landing gear of the aircraft, and wherein the respective piston head divides the second partition into a third chamber and a fourth chamber; anda directional control valve comprising: (i) a first inlet port configured to be fluidly coupled to a source of pressurized fluid, (ii) a second inlet port configured to be fluidly coupled to the source of pressurized fluid, (iii) a first tank port configured to be fluidly coupled to a tank, (iv) a second tank port configured to be fluidly coupled to the tank, (v) a first workport configured to be fluidly coupled to the first chamber, (vi) a second workport configured to be fluidly coupled ...

Mast with hydraulic circuit for assist cylinder

A mast assembly that includes a mast and a hydraulic circuit for moving the mast. The hydraulic circuit includes a primary hydraulic cylinder coupled to the mast to rotate the mast about a pivot axis and a secondary hydraulic cylinder extending from a rod end to a cap end that is fluidly coupled to the primary hydraulic cylinder. A directional valve is fluidly coupled between the primary hydraulic cylinder and secondary hydraulic cylinder to keep a pressure on the cap end of the secondary hydraulic cylinder greater than the pressure on the rod end of the secondary hydraulic cylinder during all operating conditions.

Hydraulic Control Valve, Dual-Cylinder Extension System and Aerial Work Engineering Machine

A hydraulic control valve, a dual-cylinder extension system and an aerial work engineering machine. The control valve comprises a flow distributing and collecting valve, and control valve body is provided with a first oil opening, a second oil opening and a third oil opening. A first oil opening, a second oil opening and a third oil opening of said flow distributing and collecting valve are respectively communicated with the first oil opening, the second oil opening and the third oil opening of the valve body. The control valve has two working states, wherein, in the first working state, the oil path between the second oil opening and the third oil opening of the valve body is blocked; and in the second working state, the oil path between the second oil opening and the third oil opening of the valve body is opened.

TRANSPORT VEHICLE

A control valve device () controls supply and discharge of pressurized oil to and from a hoist cylinder () which tilts a vessel (). A throttle (C) that limits a flow rate of hydraulic oil which is discharged from a hydraulic pump () and flows in a return line () through a pump line (), a first directional control valve () and a center bypass oil passage () is provided in the floating position (F) of the first directional control valve (). When the first directional control valve () is in the floating position (F), the upstream side of the throttle (C) is connected to the pump line (), and the downstream side of the throttle (C) is connected to the return line (). In addition, a rod-side actuator line () communicated with rod-side oil chambers (E, F) in the hoist cylinder () is connected to the pump line (). 1. A transport vehicle comprising:{'b': '2', 'an automotive vehicle body ();'}{'b': 3', '2, 'a vessel () which is tiltably provided on said vehicle body () in an upper-lower direction on a basis of the rear side and on which the objects to be transported are loaded;'}{'b': 12', '3', '2', '3', '12, 'a hoist cylinder () which is provided between said vessel () and said vehicle body () and tilts said vessel () upward or downward with expansion or contraction of a rod (C);'}{'b': 13', '14', '14', '13, 'a hydraulic source (, ) comprising a hydraulic oil tank () for reserving hydraulic oil therein and a hydraulic pump () for delivering hydraulic oil as the pressurized oil;'}{'b': 19', '12, 'a control valve device () for controlling supply and discharge of the pressurized oil to and from said hoist cylinder ();'}{'b': 15', '13', '19, 'a pump line () for establishing connection between said hydraulic pump () and said control valve device ();'}{'b': 17', '18', '19', '12, 'actuator lines (, ) for establishing connection between said control valve device () and said hoist cylinder (); and'}{'b': 16', '13', '19', '14, 'a return line () for returning the hydraulic oil which ...

Working Machine and Control System

A working machine including a ground engaging structure and a propulsion system for moving the working machine via the ground engaging structure. A body is supported on the ground engaging structure, and a working arm is connected to the body and has a carriage at one end for receiving an attachment. A control system is provided for selectively and variably oscillating the carriage.

Work Machine

To provide a work machine capable of efficiently regenerating the energy owned by hydraulic fluid during a swing deceleration. In the present invention, when a swing deceleration detection section 57 a detects the state of a revolving upperstructure 102 being decelerated, when an operation judgment section 57 c judges the state that a double-tilting pump/motor 14 is not supplying hydraulic fluid to any of a boom cylinder 1 and an arm cylinder 3 , and when the number of double-tilting pumps/motors 14, 18 having supplied hydraulic fluid to a swing hydraulic motor 7 in the state before the swing deceleration detection section 57 a detects the state of the revolving upperstructure 102 being decelerated is equal to one or more, a pump valve control section 57 d controls changeover valves 43 a, 45 b, 45 d, 49 d to open and increases the displacements of the double-tilting pumps/motors 14, 18 to the side to make suction pressures become higher than discharge pressures of the double-tilting pumps/motors 14, 18 so that the double-tilting pumps/motors 14, 18 operate as motors.

HYDRAULIC ACTUATOR CONTROL CIRCUIT

To reduce the cost by reducing the number of parts and simplify the control of regeneration in the hydraulic actuator even though the meter-in control and the meter-out control can be performed separately while the supply and the discharge of hydraulic fluid is controlled. A meter-in valve that controls supply flow from a hydraulic pump into a hydraulic cylinder is provided, and meter-out switching valve that switches the direction of supply and discharge of the hydraulic oil into the hydraulic cylinder and controls the discharge flow from the hydraulic cylinder to the oil tank is installed on the down stream side of the meter-in valve, and further, a regeneration control valve is installed on the down stream side of the meter-out switching valve. 1. A hydraulic actuator control circuit for controlling supply and discharge of oil to and from a hydraulic actuator , the hydraulic actuator control circuit comprising:a meter-in valve for controlling a supply flow rate from a hydraulic pump to the hydraulic actuator; anda meter-out selector valve arranged downstream of the meter-in valve configured to switch between a direction of supply of hydraulic oil to the hydraulic actuator and a direction of discharge of hydraulic oil from the hydraulic actuator while controlling a discharge flow rate from the hydraulic actuator to an oil tank.2. The hydraulic actuator control circuit according to claim 1 , further comprising a pressure compensation valve for keeping a pressure difference between an upstream side and a downstream side of the meter-in valve constant is provided upstream of the meter-in valve.3. The hydraulic actuator control circuit according to claim 1 , further comprising a recycling control valve for controlling a recycling flow rate at which discharged oil from one of oil chambers of the hydraulic actuator is supplied to the other oil chamber is provided downstream of the meter-out selector valve. The present invention relates to the technical field of a ...

Servo governor by pwm

A servo actuator is provided which may comprise a controller configured to control a plurality of solenoid valves based upon an output signal. The plurality of solenoid valves may be used to control the position of the object. For example, a set of solenoid valves, of the plurality of solenoid valves, may be configured to conduct fluid from a tank into a first chamber of the cylinder, conduct fluid from the tank into a second chamber of the cylinder, conduct fluid from the second chamber of the cylinder into a first solenoid valve and/or conduct fluid from the first chamber of the cylinder into the first solenoid valve. The first solenoid valve, of the plurality of solenoid valves, may be configured to conduct fluid from the set of solenoid valves into a vent valve based upon a pulse width modulation (PWM) signal received from the controller.

HYDRAULIC CONTROL DEVICE FOR VEHICLE TRANSMISSION APPARATUS

A hydraulic control device that includes a first layer including a first surface, a first groove having a semicircular cross-sectional shape and formed in the first surface, and a first oil passage having a circular cross-sectional shape, communicating with an end of the first groove, extending in a direction orthogonal to the first surface, and open to the first groove; a second layer including a second surface, and a second groove having a semicircular cross-sectional shape and formed in the second surface to face the first groove, the second layer being stacked on the first layer, with the second surface joined to the first surface; and a second oil passage having a circular cross-sectional shape, defined by the first groove in the first surface and the second groove in the second surface, and communicating with the first oil passage.

Apparatus for controlling a hydraulic machine

An apparatus for controlling a hydraulic machine, for example a turbine, pump or pump turbine, using variable-speed driven fixed displacement pumps. The apparatus includes a device for carrying out an emergency shut-off that is characterized by low energy consumption and high efficiency while guaranteeing all the operation-relevant and safety-relevant requirements of a hydraulic machine.

Horizontal stabilizer trim actuator systems and methods

Systems and methods are provided for a hydraulic stabilizer trim actuator (HSTA). The HSTA may operate one or more movable control surfaces. The HSTA operate responsive to commands issued by the pilot and/or by a controller and may include hydraulic architecture that minimizes the probability of an un-commanded movement or movement in the opposite direction of such commands.

Method for operating a hydraulic system and brake system

A method for operating a hydraulic system with a plurality of consumers an electrically controllable pressure supply device and an electrically actuable inlet valve, per consumer, which inlet valve is arranged between the pressure supply device and the consumer, wherein a pressure/volume relationship is predefined or determined for each consumer, wherein each consumer is assigned to a first group or a second group of consumers, wherein the first group of consumers includes at least one consumer, and wherein, in order to set predefined consumer-specific setpoint pressures, the first group of consumers is connected via the respectively opened inlet valve to the pressure supply device, and the inlet valves of the consumers of the second group are closed, wherein the inlet valve of a single, selected consumer of the second group is opened while being regulated to build up a pressure, and a brake system for motor vehicles.

Valve part and method of manufacturing valve part

A valve part that includes a body and a spool housing, wherein the spool housing has: a main body that has a hole that slidably houses a spool, a port formed in a wall surface of the hole of the main body and configured to vary a state of communication between an inside and an outside of the main body in accordance with a position of the spool, a communication hole that extends from the port toward a radially outer side, a first projection in which the communication hole is formed and which is formed so as to project from an outside surface of the main body toward the radially outer side, and a first opening at which the communication hole opens at a distal end of the first projection.

Switching unit and pneumatic system

A switching unit may be provided for connecting a first pneumatic unit and a second pneumatic unit of a pneumatic system together. The switching unit comprises a main body having: a channel structure which extends through the main body; a first and a second inlet for introducing a pressure into the channel structure; a first and a second outlet for discharging at least some of the pressure from the channel structure; and a first and a second valve; wherein the first inlet can be brought into a pressure-exchange connection to the first outlet via a first channel by setting a first switch position of the first valve or to the second outlet via a second channel by setting a second switch position of the first valve, and wherein the second inlet can be brought into a pressure-exchange connection to the first outlet via a third channel by setting a first switch position of the second valve or to the second outlet via a fourth channel by setting a second switch position of the second valve.

Working machine

A working machine includes a prime mover, a hydraulic pump driven by power of the prime mover, a cooler including a cooling fan rotated by either the power of the prime mover or hydraulic fluid delivered from the hydraulic pump, and a controller configured or programmed to perform a reduction control for reducing a target fan rotation speed that is a target rotation speed of the cooling fan in response to reduction of an actual prime mover rotation speed that is an actual rotation speed of the prime mover, and to perform, after the reduction control, a restoration control for restoring the target fan rotation speed. The controller is configured or programmed to make a difference between a reduction rate of the target fan rotation speed in the reduction control and an increase rate of the target fan rotation speed in the restoration control.

Pilot control mechanism for boom bounce reduction

A hydraulic system (600) and method for reducing boom dynamics of a boom (30), while providing counter-balance valve protection, includes a hydraulic actuator (110), first and second counter-balance valves (300, 400), first and second control valves (700, 800), and first and second blocking valves (350, 450). A net load (90) is supported by a first chamber (116, 118) of the hydraulic actuator, and a second chamber (118, 116) of the hydraulic actuator may receive fluctuating hydraulic fluid flow from the second control valve to produce a vibratory response (950) that counters environmental vibrations (960) on the boom. The first blocking valve prevents the fluctuating hydraulic fluid flow from opening the first counter-balance valve. The first blocking valve may drain leakage from the first counter-balance valve.

Work machine

The present invention provides a work machine including a steering device that is very responsive to switching operations. The work machine includes: a proportional solenoid valve for outputting a first pilot pressure oil with a pressure responding to a steering signal; a solenoid valve for outputting a second pilot pressure oil with a predetermined pressure while the steering signal is outputted from the steering device; a switching valve capable of switching to a first state of outputting the first pilot pressure oil to a directional control valve and a second state of outputting the second pilot pressure oil to the directional control valve, while the first pilot pressure oil is outputted from the proportional solenoid valve and the second pilot pressure oil is outputted from the solenoid valve in parallel; and a controller to switch the switching valve from the first state to the second state in a case where a malfunction is detected in a main circuit ranging from the steering device to the directional control valve via the proportional solenoid valve and the switching valve of the first state.

HYDRAULIC DRIVING DEVICE OF INDUSTRIAL VEHICLE

A hydraulic driving device of an industrial vehicle includes: a tank which stores hydraulic oil; a hydraulic pump which includes a suction port sucking the hydraulic oil and a discharge port discharging the hydraulic oil; a hydraulic cylinder which is driven by the hydraulic oil discharged from the discharge port of the hydraulic pump; a direction switching valve which is disposed among the hydraulic pump, the tank, and the hydraulic cylinder and switches a hydraulic oil flow direction in response to an operation state of operation means for driving the hydraulic cylinder; in which the direction switching valve includes a main spool which moves in response to the operation state of the operation means and a flow regulator which is disposed inside the main spool to control a flow rate of the hydraulic oil flowing from the hydraulic cylinder to the tank. 1. A hydraulic driving device of an industrial vehicle comprising:a tank which stores hydraulic oil;a hydraulic pump which includes a suction port sucking the hydraulic oil and a discharge port discharging the hydraulic oil;a hydraulic cylinder which is driven by the hydraulic oil discharged from the discharge port of the hydraulic pump;a direction switching valve which is disposed among the hydraulic pump, the tank, and the hydraulic cylinder and switches a hydraulic oil flow direction in response to an operation state of operation means for driving the hydraulic cylinder;wherein the direction switching valve includes a main spool which moves in response to the operation state of the operation means and a flow regulator which is disposed inside the main spool to control a flow rate of the hydraulic oil flowing from the hydraulic cylinder to the tank.2. The hydraulic driving device of the industrial vehicle according to claim 1 , further comprising:a common hydraulic oil passage which connects the hydraulic cylinder to the direction switching valve so that the hydraulic oil flows in both directions between the ...

Pneumatic trip valve

A pneumatic trip valve that may include a valve structure, a switch plate air path and an internal check valve. In various aspects, the pneumatic trip valve may be connected to a valve positioner, an actuator, or a combination thereof to control the operation of a fluid process control valve. In operation, the Pneumatic trip valve acts to put the actuator in a preset fail-safe position when the actuator loses sufficient pressure or communication from a main air supply, stored pressurized air from an actuator air reservoir, and/or an external air reservoir.

Breaker auto-synchronizer

A breaker between two electrical circuits is provided that is closed when electrical properties in both of the electrical circuits are matching. Two check circuits are provided for comparing electrical properties of the two electrical circuits. Each of the check circuits sets a corresponding authorization to close the breaker. The breaker is only closed if both check circuits set an authorization to close the circuit.

Hydraulic circuit for controlling a movable component

Hydraulic circuits for controlling a movable component use one or more of a plurality of fluid supplies. Pressurized fluid flowing from one supply is routed toward the component and is not inadvertently vented into another fluid supply, or into an exit port. A backflow path is provided for fluid returning from the hydraulic component when the component is actuated in a reversed direction. The hydraulic circuits can be used, for example, on blowout preventers in a subsea environment.

System and method for remotely controlling hydraulic components of an agricultural implement

A system for remotely controlling hydraulic component of an agricultural implement towed by a work vehicle may include a vehicle-based valve assembly that selectively supplies hydraulic fluid to one or more supply lines of the implement. Specifically, a first supply line may be fluidly coupled to an implement-based valve assembly that regulates the supply of hydraulic fluid to a hydraulic actuator through a first actuator line. A second supply line may be fluidly coupled to the first actuator line downstream of the implement-based valve assembly such that when a user provides a control input at a remote interface, the vehicle-based valve assembly may instead regulate the supply of hydraulic fluid to the actuator. The supply of the hydraulic fluid through the supply lines may additionally be controlled by first and second override valves fluidly coupled to the first and second supply lines, respectively.

HYDRAULIC CIRCUIT FOR CONSTRUCTION MACHINE AND CONTROL DEVICE FOR SAME

A hydraulic circuit for a construction machine including a center bypass passage including a group of directional control valves arranged in tandem; and a bleed-off valve arranged in the center bypass passage on a downstream side of the group, wherein each directional control valve includes a first internal passage causing the pressurized oil supplied to the directional control valve to flow out to the center bypass passage and a second internal passage supplying the pressurized oil to a cylinder port, wherein a parallel passage is formed by the center bypass passage and the first internal passage by causing the pressurized oil discharged from the hydraulic pump to flow to the center bypass passage on the downstream of the directional control valve, wherein the second internal passage supplies the pressurized oil from the center bypass passage through an opening of a spool and/or the bypass passage to the cylinder port. 1. A hydraulic circuit for a construction machine including a center bypass passage , into which a pressurized oil discharged from a hydraulic pump is supplied , the hydraulic circuit comprising:a directional control valve group including a plurality of directional control valves arranged in tandem with the center bypass passage; anda bleed-off valve arranged in the center bypass passage on a downstream side of the directional control valve group,wherein each directional control valve includes a first internal passage for causing the pressurized oil supplied to the directional control valve to flow out to the center bypass passage and a second internal passage for supplying the pressurized oil to a cylinder port,wherein a parallel passage is formed by the center bypass passage and the first internal passage by causing, by the first internal passage, the pressurized oil discharged from the hydraulic pump to flow out to the center bypass passage on the downstream side of the directional control valve,wherein the second internal passage supplies the ...

Control of hydraulic actuating cylinders in roll stands

A hydraulic control loop controls a hydraulic adjusting cylinder. The cylinder has a cylindrical housing and a displaceable piston therein. The piston divides the housing interior into a first and a second hydraulic chamber. A first hydraulic valve supplies the first hydraulic chamber with hydraulic fluid. A hydraulic pressure of the first hydraulic chamber is adjustable by controlling the first hydraulic valve. A second hydraulic valve supplies the second hydraulic chamber with hydraulic fluid. A hydraulic pressure of the second hydraulic chamber is adjustable by controlling the second hydraulic valve. A control device controls the two hydraulic valves. In a position control state, the second hydraulic valve is controlled by a position control signal dependent on the working position of the piston and the first hydraulic valve is controlled by an adjusted position control signal, that is generated on the basis of the position control signal.

FLUID CONTROL VALLVE

A fluid control valve includes a first flow path and a second flow path that connect a first port and a second port in parallel. The first flow path includes an opening and closing valve mechanism that temporarily opens the first flow path. The second flow path includes a throttle valve mechanism that restrictedly opens the second flow path. The opening and closing valve mechanism includes an opening and closing valve portion including an opening and closing valve seat and an opening and closing valve body, a valve opening force generator, and a delay valve closing mechanism that closes the opening and closing valve body after a delay time has elapsed. The throttle valve mechanism includes a throttle valve portion. The opening area of the opening and closing valve portion is larger than the opening area of the throttle valve portion. 1. A fluid control valve comprising a first port and a second port provided in a valve body , and a first flow path and a second flow path that connect the first port and the second port in parallel ,wherein the first flow path is provided with an opening and closing valve mechanism that temporarily opens the first flow path when pressure fluid is supplied to the first port,wherein the second flow path is provided with a throttle valve mechanism that restrictedly opens the second flow path,wherein the opening and closing valve mechanism has an opening and closing valve portion including an opening and closing valve seat that surrounds the first flow path and an opening and closing valve body that comes into contact with and separates from the opening and closing valve seat to open and close the first flow path, a valve opening force generating means that generates a valve opening force in the opening and closing valve body, and a delay valve closing mechanism that closes the opened opening and closing valve body after a delay time has elapsed,wherein the throttle valve mechanism has a throttle valve portion including a throttle hole ...

LOW PROFILE ELECTRO-HYDROSTATIC ACTUATOR

In general, certain embodiments of the present disclosure provide an electro-hydrostatic actuator comprising a piston assembly and a hydraulic cylinder. The piston assembly, having a piston head and a piston rod extending from the piston head, is located and movable within the hydraulic cylinder. The hydraulic cylinder includes a hydraulic fluid chamber region including a piston side chamber and a rod side chamber, a reservoir for storing hydraulic fluid located within the hydraulic cylinder which is in fluid communication with the hydraulic fluid chamber region. The electro-hydrostatic actuator includes a hydraulic pump system for moving hydraulic fluid in the reservoir and the hydraulic fluid chamber region, the hydraulic pump system in fluid communication with a flow control network in a hydraulic cylinder boss for controlling a direction and flow magnitude of hydraulic fluid within the hydraulic fluid chamber region, and an electric motor for driving the hydraulic pump system. 1100. An electro-hydrostatic actuator () , comprising:{'b': 20', '26', '22, 'a piston assembly () having a piston head () and a piston rod () extending from the piston head;'}{'b': 30', '210', '28', '32', '34, 'a hydraulic cylinder (, ), wherein the piston assembly is located and movable within the hydraulic cylinder, the hydraulic cylinder including a hydraulic fluid chamber region () including a piston side chamber () and a rod side chamber ();'}{'b': '36', 'a reservoir () for storing hydraulic fluid located within the hydraulic cylinder which is in fluid communication with the hydraulic fluid chamber region;'}{'b': 40', '38', '211, 'a hydraulic pump system () for moving hydraulic fluid in the reservoir and the hydraulic fluid chamber region, the hydraulic pump system in fluid communication with a flow control network () in a hydraulic cylinder boss () for controlling a direction and flow magnitude of hydraulic fluid within the hydraulic fluid chamber region; and'}{'b': '50', 'an ...

HYDRAULIC SYSTEM HAVING DUAL TILT BLADE CONTROL

A hydraulic system for a machine is disclosed. The hydraulic system may have a tank configured to hold a supply of fluid, a pump configured to draw fluid from the tank and pressurize the fluid, a first cylinder operatively connected between a first side of a work tool and an undercarriage of the machine, and a second cylinder operatively connected between a second side of the work tool and the undercarriage of the machine. The hydraulic system may also have a first electro-hydraulic valve associated with the first cylinder and configured to selectively regulate a flow of pressurized fluid to the first cylinder independently of the second cylinder, and a second electro-hydraulic valve associated with the second cylinder and configured to selectively regulate a flow of pressurized fluid to the second cylinder independently of the first cylinder. 1. A hydraulic system for a machine , comprising:a tank configured to hold a supply of fluid;a pump configured to draw fluid from the tank and pressurize the fluid;a first cylinder operatively connected between a first side of a work tool and a first undercarriage assembly of the machine;a second cylinder operatively connected between a second side of the work tool and a second undercarriage assembly of the machine;a first electro-hydraulic valve associated with the first cylinder and configured to selectively regulate a flow of pressurized fluid to the first cylinder independently of the second cylinder; anda second electro-hydraulic valve associated with the second cylinder and configured to selectively regulate a flow of pressurized fluid to the second cylinder independently of the first cylinder.2. The hydraulic system of claim 1 , wherein each of the first and second electro-hydraulic valves includes:a main spool that is pilot-operated to move between a first position at which pressurized fluid from the pump is directed to a head-end of an associated one of the first and second cylinders and fluid from a rod-end of the ...

System and method for spool fault detection of solenoid valves using electrical signature

The present disclosure relates to a system for monitoring a solenoid operated valve including at least one coil and at least one spool. The system compares a normalized current signature and a normalized current signature comparator to determine a spool fault condition

HYDRAULIC EXCAVATOR DRIVE SYSTEM

A hydraulic excavator drive system includes: a control valve for a cylinder that swings a swinging unit; an operation device that outputs an operation signal in accordance with an inclination angle of an operating lever when receiving a first operation of moving the swinging unit closer to a cabin or a second operation of moving the swinging unit farther from the cabin; a solenoid proportional valve connected to a first pilot port of the control valve, the first pilot port being intended for the first operation; and a controller that, when the operation device receives the first operation, controls the solenoid proportional valve such that: a pilot pressure outputted from the solenoid proportional valve is proportional to the operation signal outputted from the operation device until the pilot pressure reaches an upper limit pressure; and the closer the swinging unit to the cabin, the higher the upper limit pressure. 1. A hydraulic excavator drive system comprising:a cylinder that swings a swinging unit that is an arm or a bucket;a control valve that controls supply and discharge of hydraulic oil to and from the cylinder, the control valve including a first pilot port for a first operation of moving the swinging unit closer to a cabin and a second pilot port for a second operation of moving the swinging unit farther from the cabin;an operation device that includes an operating lever and that outputs an operation signal in accordance with an inclination angle of the operating lever when receiving the first operation or the second operation;a solenoid proportional valve connected to the first pilot port; anda controller that controls the solenoid proportional valve based on the operation signal, wherein a pilot pressure outputted from the solenoid proportional valve is proportional to the operation signal outputted from the operation device until the pilot pressure reaches an upper limit pressure; and', 'the closer the swinging unit is to the cabin, the higher the ...

ELECTROHYDRAULIC CONTROL CIRCUIT

An electrohydraulic control circuit for driving a hydraulically actuated actuating element (), by means of which a segment () of a manipulator, in particular of a large manipulator for truck-mounted concrete pumps, can be adjusted in terms of its orientation, wherein there are provided an electrically driven first valve (), which is connected to hydraulic working lines of the actuating element () for the drive thereof, and leak-free check valves () provided in the working lines of the actuating element (), which valves are arranged on the actuating element () or on the segment () associated with this actuating element () and can be released for the normal operation of the actuating element (), wherein the release of the check valves () is driven by an electronic control unit (ECU) separate from the first valve () and the check valves (). 1. An electrohydraulic control circuit for driving a hydraulically actuated actuating element , by means of which a segment of a manipulator , in particular of a large manipulator for truck-mounted concrete pumps , can be adjusted in terms of its orientation , comprising:an electrically driven first valve, which is connected to hydraulic working lines of the actuating element, andcheck valves provided in the working lines of the actuating element, which check valves are arranged on the actuating element or on the segment associated with the actuating element and can be released for the normal operation of the actuating element,wherein the release of the check valves is driven by an electronic control unit separate from the first valve and the check valves.2. The control circuit of claim 1 , wherein a first valve is arranged on the actuating element or segment associated with the actuating element.3. The control circuit of claim 1 , wherein the control unit is formed as a dedicated electronic unit for the segment.4. The control circuit of claim 1 , wherein the working lines of the actuating element are equipped with pressure sensors ...

HYDRAULIC DRIVE WITH RAPID STROKE AND LOAD STROKE

A hydraulic drive including a first differential cylinder that includes a first and a second pressure chamber and a first piston that separates the first from the second pressure chamber and having two pumps delivering in opposite direction. The hydraulic drive further includes a second differential cylinder that includes a first and a second pressure chamber and a second piston that separates the first pressure chamber from the second pressure chamber, and a directional control valve that has a first and a second switching position. The pumps in the first switching position are respectively hydraulically connected via pressure chambers of the first differential cylinder that are different from each other and whereby the pumps in the second switching position are respectively connected via pressure chambers of the second differential cylinder that are different from each other. 1. A hydraulic drive for a hydraulic press , said hydraulic drive comprising:a first pump and a second pump delivering in an opposite direction; a first pressure chamber and a second pressure chamber; and', 'a first piston that separates said first pressure chamber from said second pressure chamber;, 'a first differential cylinder, including a first pressure chamber and a second pressure chamber; and', 'a second piston that separates the first pressure chamber from the second pressure chamber of the second differential cylinder; and, 'a second differential cylinder, includinga directional control valve that has a first switching position and a second switching position, wherein said first pump and said second pump in the first switching position are respectively hydraulically connected via said first pressure chamber and said second pressure chamber of the first differential cylinder, and wherein said first pump and said second pump in the second switching position are respectively connected via said first pressure chamber and said second pressure chamber of the second differential cylinder.2 ...

HYDRAULIC DRIVE WITH RAPID STROKE AND LOAD STROKE

A hydraulic drive including at least one hydraulic cylinder that includes a piston chamber, an annulus and a piston that separates the piston chamber from the annulus. The hydraulic drive further includes a first hydraulic pump that has a pump intake and a pump outlet, a directional control valve that has a first and a second switching position, and a second hydraulic pump. The second hydraulic pump has a direction of delivery that is consistent with the direction of delivery of the first hydraulic pump at the pump outlet, wherein the second hydraulic pump in the first switching position of the directional control valve is hydraulically connected with the piston chamber and the second hydraulic pump in the second switching position of the directional control valve is not hydraulically connected with the piston chamber. 1. A hydraulic drive for a hydraulic press , said hydraulic drive comprising: a piston chamber and an annulus; and', 'a piston that separates said piston chamber from said annulus;, 'at least one hydraulic cylinder, including a pump intake hydraulically connected with said annulus; and', 'a pump outlet hydraulically connected with said piston chamber;, 'a first hydraulic pump having a direction of delivery, said first hydraulic pump includinga second hydraulic pump having a direction of delivery that is consistent with said direction of delivery of the first hydraulic pump at said pump outlet; anda directional control valve that has a first switching position and a second switching position, wherein said second hydraulic pump in said first switching position of the directional control valve is hydraulically connected with said piston chamber and wherein said second hydraulic pump in said second switching position of the directional control valve is not hydraulically connected with said piston chamber.2. The hydraulic drive according to claim 1 , wherein said first hydraulic pump is in the form of a four-quadrant pump.3. The hydraulic drive according ...

METHODS AND HYDRAULIC APPARATUS

Methods can comprise charging a first hydraulic device of a first hydraulic circuit with a first quantity of hydraulic fluid from a hydraulic fluid source. The methods can further comprise pressurizing a control segment and locking the first quantity of hydraulic fluid from exiting the first hydraulic circuit in response to hydraulic pressure within the control segment. The methods can also include unlocking the first quantity of hydraulic fluid to permit exiting of the first quantity of hydraulic fluid from the first hydraulic device in response to dropping the hydraulic pressure within the control segment after a delay. Hydraulic apparatus can comprise a normally open hydraulic pilot operated control valve that can be configured to hydraulically lock a first hydraulic device in response to a hydraulic pressure within a control segment rising to greater than or equal to an actuation pressure. 1. A method comprising:placing a hydraulic fluid source in communication a first hydraulic circuit;charging a first hydraulic device of the first hydraulic circuit with a first quantity of hydraulic fluid from the hydraulic fluid source;pressurizing a control segment of the first hydraulic circuit with the hydraulic fluid source to a hydraulic pressure greater than or equal to an actuation pressure;locking the first quantity of hydraulic fluid from exiting the first hydraulic circuit in response to the hydraulic pressure within the control segment reaching greater than or equal to the actuation pressure;preventing further communication between the hydraulic fluid source and the first hydraulic circuit; andunlocking the first quantity of hydraulic fluid to permit exiting of the first quantity of hydraulic fluid from the first hydraulic device in response to dropping the hydraulic pressure within the control segment below the actuation pressure after a delay of about 0.5 seconds or more from the preventing further communication between the hydraulic fluid source and the first ...

Valve Module, Valve Assembly and Method for Operating a Valve Assembly

A valve module for mounting to a fluid distribution device, including a main body, which has two mutually opposed interface surfaces, which are designed for connection to a valve module or to a fluid distribution device wherein a distribution device connection for fluid coupling to a distribution device connection of the fluid distribution device or to a distribution device connection of another valve module and a working connection for fluidic coupling to a working connection of the fluid distribution device or a working connection of another valve module, is formed on each of the interface surfaces, wherein the main body is permeated by a fluid channel which extends between the two distribution device connections and the two working connections and to which a valve device is assigned to influence an open fluid channel cross-section. 1. A method for operating a valve assembly , having a parallel fluid connection of a plurality of valve modules , comprising the steps of:determining a fluid flow requirement by means of a control unit with reference to a predeterminable discharge or an external requirement signal;generating a control signal group in the control unit according to the fluid flow requirement; andproviding the control signal group from the control unit to control circuits of the valve devices assigned in each case, wherein the control signal group for each valve device has an individual control signal.2. The method according to claim 1 , wherein the individual control signals are determined according to predeterminable threshold values for the respective valve device claim 1 , the threshold values being linked to the fluid flow requirement.3. The method according to claim 1 , wherein claim 1 , according to the threshold values claim 1 , in each case claim 1 , activation ranges for the respective valve devices are determined within the fluid flow requirement claim 1 , which ranges are selected in such a way that claim 1 , in the case of a low fluid flow ...

LANDING GEAR LIFTING/LOWERING EHA SYSTEM

A landing gear lifting/lowering EHA system includes: a hydraulic actuator configured to lift and lower the leg of an aircraft; at least one electrically operated hydraulic pump; a hydraulic path; a pressure sensor attached to the hydraulic actuator or the hydraulic path and configured to output a measurement signal corresponding to hydraulic pressure; and a controller configured to output a control signal to the electrically operated hydraulic pump, wherein, when a state in which the hydraulic pressure exceeds a set pressure continues for a set time, the control unit stops the electrically operated hydraulic pump in operation and resumes the operation of the electrically operated hydraulic pump after the hydraulic pressure drops to or below a second set pressure after the electrically operated hydraulic pump is stopped.

FLUID PRESSURE CONTROL DEVICE

A fluid pressure control device includes a switching valve that operates in conjunction with a control valve by a pilot pressure to switch an operation of an operated check valve. The switching valve includes a spool that moves according to the pilot pressure of a pilot chamber, and a piston that is accommodated in the pilot chamber and imparts a thrust force to the spool upon receiving the pilot pressure. The piston includes a first piston that is slidingly accommodated in the pilot chamber and is acted upon by the pilot pressure, and a second piston whose distal end faces the spool and is inserted into an accommodating hole formed in the first piston. A spherical protrusion is provided on a center of either one of a bottom surface of the accommodating hole of the first piston and a back surface of the second piston. 1. A fluid pressure control device comprising:a cylinder that extends/retracts to drive a load by a working fluid supplied from a pump;a control valve that switches supply/discharge of the working fluid to/from the cylinder to control an extension/retraction operation of the cylinder;a pilot valve that pilot operates the control valve by a pilot pressure;a main passage that connects the control valve to a load-side pressure chamber of the cylinder on which a load pressure by the load acts when the control valve is in a blocked position; anda load-retaining mechanism that is interposed in the main passage and retains the load pressure of the load-side pressure chamber when the control valve is in the blocked position,wherein the load-retaining mechanism comprises:an operated check valve that permits a flow of the working fluid from the control valve to the load-side pressure chamber while also permitting a flow of the working fluid from the load-side pressure chamber to the control valve according to a pressure of a back pressure chamber to which pressure of the load-side pressure chamber is constantly led via a restriction passage; anda switching valve ...

Simultaneous Push-Pull Workstation for Frame Straightening

A portable workstation includes a frame, a plurality of wheels coupled to the frame, a handle coupled to the frame, a pneumatic inlet port coupled to the frame and a pump coupled to the frame and pneumatically coupled to the pneumatic inlet port. The pump pumps hydraulic fluid. A plurality of hydraulic outlet ports is coupled to the frame and is hydraulically coupled to the pump. 1. A portable workstation comprising:a tray or basket;a frame comprising a plurality of vertical members;a plurality of wheels coupled to the frame;a handle coupled to the vertical members of the frame;a hose support coupled to the vertical members;a pneumatic inlet port and a pneumatic outlet port coupled to the frame;a dual acting ram support arm coupled to the vertical members of the frame;a directional converter coupled to the frame and hydraulically coupled to the pump, said directional converter comprising a pair of push pull ports, said push pull ports coupled to a dual acting ram;said pump coupled to the frame and pneumatically coupled to the pneumatic inlet port, said pump pumping hydraulic fluid; anda plurality of hydraulic outlet ports coupled to the frame and hydraulically coupled to the pump coupled to a single action actuator.2. The portable workstation as recited in wherein the frame or basket comprises a first basket coupled to the frame.3. The portable workstation as recited in wherein the frame or basket comprises a second basket coupled to the frame.4. The portable workstation as recited in wherein the second basket is below the first basket.5. The portable workstation as recited in wherein the frame or basket comprises a tray claim 4 , a first basket and a second basket.6. The portable workstation as recited in further comprising a hose guide coupled to the frame.7. The portable workstation as recited in further comprising a hydraulic directional converter hydraulically coupled to the pump for coupling to a dual-acting hydraulic actuator.8. The portable workstation as ...

DITHERING HYDRAULIC VALVES TO MITIGATE STATIC FRICTION

A method and apparatus for dithering hydraulic valves to mitigate static friction (“stiction”) associated with the hydraulic valves. A first hydraulic valve and a second hydraulic valve are dithered to mitigate stiction associated with those valves. The dithering of the first and second hydraulic valves also cause dithering of a main hydraulic valve associated with the first and second hydraulic valves. Accordingly, stiction of three hydraulic valves of a hydraulic system is mitigated. 1. A method comprising:dithering a first hydraulic valve to produce a first periodically varying hydraulic fluid pressure applied to a first input of a second hydraulic valve; anddithering a third hydraulic valve to produce a second periodically varying hydraulic fluid pressure 180 degrees out of phase with the first periodically varying hydraulic fluid pressure and applied to a second input of the second hydraulic valve,wherein the first periodically varying hydraulic fluid pressure and the second periodically varying fluid pressure applied to the first input and the second input of the second hydraulic valve cause the second hydraulic valve to dither.2. The method of claim 1 , wherein the dithering of the second hydraulic valve causes hydraulic fluid pressure to be applied to a first input of a hydraulic cylinder and a second input of a hydraulic cylinder claim 1 , wherein the hydraulic fluid pressure applied is a value lower than a value required to actuate the hydraulic cylinder.3. The method of claim 1 , wherein the dithering of the first hydraulic valve is in response to a periodically varying hydraulic fluid pressure applied to a first input of the first hydraulic valve and a periodically varying hydraulic fluid pressure applied to a second input of the first hydraulic valve.4. The method of claim 3 , wherein the dithering of the third hydraulic valve is in response to a periodically varying hydraulic fluid pressure applied to a first input of the third hydraulic valve and a ...

FLUID PRESSURE CONTROL DEVICE

A fluid pressure control device includes a first circuit system having a first pump and a first control valve. The first circuit system includes an intermediate cut valve provided downstream of the first control valve in a first intermediate passage and which connects and disconnects a connection between the first intermediate passage and the tank, and an external output port communicating at a part downstream of the first control valve in the first intermediate passage and upstream of the intermediate cut valve, the external output port being capable of externally supplying working fluid discharged from the first pump. 1. A fluid pressure control device adapted to control a first actuator and a second actuator driven by working fluid supplied from a first pump and a second pump , comprising:a first circuit system connected to the first pump and having a first control valve adapted to control the first actuator; anda second circuit system connected to the second pump and having a second control valve adapted to control the second actuator,the first circuit system having:a first intermediate passage adapted to return the working fluid of the first pump to a tank when the first control valve is in an intermediate position;an intermediate cut valve provided downstream of the first control valve in the first intermediate passage, the intermediate cut valve being adapted to connect and disconnect a connection between the first intermediate passage and the tank; andan external output port connected to a part downstream of the first control valve and upstream of the intermediate cut valve in the first intermediate passage, the external output port being capable of supplying working fluid discharged from the first intermediate passage to a device other than the first actuator.2. The fluid pressure control device according to claim 1 , whereinthe intermediate cut valve includes: a valve block having a housing hole; and a valve body housed in the housing hole, the valve body ...

Method to Detect Uncommanded Spool Valve Positioning and Stop Fluid Flow to Hydraulic Actuators

A system and method for detecting uncommanded positioning of at least one valve spool in a plurality of valve spools and for stopping fluid flow to a plurality of hydraulic actuators fluidly connected to the plurality of valve spools is disclosed. The method may comprise receiving a signal fluid pressure detected in a signal passageway, identifying whether at least one activation command is currently enabled, and stopping the flow of fluid to the plurality of hydraulic actuators if no activation command is enabled for any of the plurality of valve spools, and the signal fluid pressure when detected (1) upstream of the plurality of valve spools is greater than a first threshold or (2) downstream of the plurality of valve spools is less than a second threshold.

Electrohydrostatic actution system, hydraulic circuit of electrohydrostatic actution system, and steam turbine system including same

Provided is an electrohydrostatic actuation system including an emergency shut-off circuit to be actuated stably with a simple configuration. The electrohydrostatic actuation system includes: a hydraulic cylinder ( 24 ) including a piston ( 25 ) to which a valve element is connected, a first chamber ( 24 A), and a second chamber ( 24 B); a hydraulic pump ( 21 ) configured to supply hydraulic fluid to the first chamber ( 24 A) or the second chamber ( 24 B); a servo motor (M) configured to drive the hydraulic pump ( 21 ); a shuttle valve ( 11 ) configured to establish communication to a downstream side under a state in which a hydraulic pressure generated by the hydraulic pump ( 21 ) is maintained; a solenoid valve ( 12 ) configured to receive the hydraulic pressure via the shuttle valve ( 11 ) as a pilot pressure; and a logic valve ( 13 ) including a first port configured to receive the pilot pressure from the solenoid valve ( 12 ), and a second port to be communicated to the first chamber ( 24 A) of the hydraulic cylinder ( 24 ). When the solenoid valve ( 12 ) is brought to a de-energized state, the pilot pressure of the logic valve ( 13 ) is released, and the logic valve ( 13 ) causes the hydraulic fluid in the first chamber ( 24 A) communicated to the second port to flow into the second chamber ( 24 B) so that emergency shut-off of the valve element is achieved by a return spring ( 26 ).

VEHICLE HYDRAULIC SYSTEM

A vehicle hydraulic system includes: (a) a hydraulic pump device to be driven by a vehicle drive source to eject a working fluid through first and second outlet ports; (b) a first line passage that guides the working fluid ejected through the first outlet port, with a hydraulic pressure being regulated to a relatively high value; (c) a downstream-side passage in which the hydraulic pressure is regulated to a relatively low value; (d) a path-switching valve device configured to allow the working fluid ejected through the second outlet port, to flow into the first line passage, when the hydraulic pressure is lower than a predetermined value, and configured to allow the working fluid ejected through the second outlet port, to flow into the downstream-side passage, when the hydraulic pressure is higher than the predetermined value; and (e) a bypass passage provided between the second outlet port and the downstream-side passage. 1. A hydraulic system for a vehicle , comprising:a hydraulic pump device which is to be driven by a vehicle drive source of the vehicle to eject a working fluid through first and second outlet ports of said hydraulic pump device;a first line passage that guides at least the working fluid ejected through said first outlet port, with a hydraulic pressure in said first line passage being regulated to a first line pressure value;a downstream-side passage in which the hydraulic pressure is regulated to a downstream-side pressure value that is lower than the first line pressure value;a first path-switching valve device which is configured to allow the working fluid ejected through said second outlet port, to flow into said first line passage, when the hydraulic pressure in said first line passage is lower than a first predetermined pressure value, and which is configured to allow the working fluid ejected through said second outlet port, to flow into said downstream-side passage, when the hydraulic pressure in said first line passage is higher than the ...

SPOOL VALVE

A spool valve includes a valve portion that opens and closes a portion between an input port and an output port and a radial-direction-position changing portion provided in an outer lateral surface of the valve portion in a radial direction. When a first value is equivalent to or larger than a threshold that is larger than 0, the portion between the input port and the output port are opened to permit a flow of the oil inside the first connection oil passage, and when the first value is smaller than the threshold, the portion is closed to block the flow of the oil inside the first connection oil passage. The radial-direction-position changing portion extends in the axial direction, and a position thereof in the radial direction changes inwardly from a first side towards a second side in the axial direction. 1. A spool valve provided in a valve mechanism included in a hydraulic control that includes a first oil supply source that draws in oil and discharges the oil having a first oil flow characteristic , a second oil supply source that draws in the oil and discharges the oil that has a second oil flow characteristic , a first output side oil passage into which the oil discharged from the first oil supply source flows , the first output side oil passage supplying hydraulic pressure to a controlled object , a second output side oil passage into which the oil discharged from the second oil supply source flows , a first connection oil passage that connects the first output side oil passage and the second output side oil passage to each other , and the valve mechanism provided with a spool hole , the valve mechanism being provided in the first connection oil passage , the spool hole including an input port connected to the second output side oil passage and an output port connected to the first output side oil passage , the spool valve provided in the valve mechanism about a central axis that extends in an axial direction being movable inside the spool hole in the axial ...

SERVOVALVE

A servovalve includes a supply port and a control port; a moveable valve spool arranged to regulate flow of fluid from the supply port to the control port in response to a control signal and a drive assembly configured to axially move the valve spool relative to the fluid transfer assembly in response to the control signal to regulate the fluid flow; wherein the drive assembly comprises a first fluid channel providing a flow path for fluid from the supply port to a first end of the spool and provided with a first flow control orifice. The assembly also includes a second fluid channel providing a rotating element provided with a cam profile located between the first flow control orifice and the second flow control orifice. The assembly also includes drive means arranged to rotate the rotating element. 1. A servovalve comprising:{'sub': A', 'B, 'a fluid transfer valve assembly comprising a supply port and a control port (P, P);'}a moveable valve spool arranged to regulate flow of fluid from the supply port to the control port in response to a control signal; anda drive assembly configured to axially move the valve spool relative to the fluid transfer assembly in response to the control signal to regulate the fluid flow; a first fluid channel providing a flow path for fluid from the supply port to a first end of the spool and provided with a first flow control orifice;', 'a second fluid channel providing a flow path for fluid from the supply port to a second end of the spool and provided with a second flow control orifice;', 'a rotating element provided with a cam profile, located between the first flow control orifice and the second flow control orifice; and', 'drive means arranged to rotate the rotating element to vary the rotational position of the cam profile with respect to the first and second flow control orifice, in response to the control signal, to control flow from the first and second flow control orifices and thus to control movement of the valve spool., ' ...

HYDRAULIC SYSTEM OF WORK MACHINE AND WORK MACHINE

A hydraulic system of a work machine includes a first hydraulic device to operate in a first operation mode while pressure of hydraulic oil supplied from a hydraulic pump via a first oil passage is equal to or higher than a first pressure threshold. The hydraulic oil in the first oil passage is to be discharged via a second oil passage. A pilot check valve is provided in the second oil passage and has a pilot port to receive a pilot pressure of the hydraulic oil. The pilot check valve is closed to stop discharging the hydraulic oil in the first oil passage through the second oil passage while the pilot pressure is lower than the fourth pressure threshold. The pilot check valve is opened while the pilot pressure is higher than or equal to the fourth pressure threshold. The first hydraulic device is a ride control device. 1. A hydraulic system of a work machine , comprising:a hydraulic pump to discharge hydraulic oil;a first hydraulic device to operate in a first operation mode while pressure of the hydraulic oil supplied from the hydraulic oil is equal to or higher than a first pressure threshold;a first oil passage which connects the first hydraulic device and the hydraulic pump and via which the hydraulic oil is to be supplied to the first hydraulic device from the hydraulic pump;a second oil passage which is connected to the first oil passage and via which the hydraulic oil in the first oil passage is to be discharged;a pilot check valve provided in the second oil passage and having a pilot port to receive a pilot pressure of hydraulic oil, the pilot pressure being controlled to be a pressure lower than a fourth pressure threshold when an operation mode of the first hydraulic device is changed to the first operation mode, the pilot check valve being closed to stop discharging the hydraulic oil in the first oil passage through the second oil passage while the pilot pressure is lower than the fourth pressure threshold, the pilot valve being opened such that the ...

Hydraulic system in work machine

A hydraulic system in of a work machine includes a hydraulic pump to supply pilot hydraulic oil in a hydraulic oil reservoir. A travel pump is to drive a travel motor according to a pilot pressure of the pilot hydraulic oil. A target pilot pressure of the pilot hydraulic oil is input through a travel operation device to control, according to the target pilot pressure, the pilot pressure supplied from the hydraulic pump to the travel pump. A pilot oil path connects the travel operation device and the travel pump to supply the pilot pressure to the travel pump. A drain oil path is divided from the pilot oil path. A pressure adjustment valve is provided in the drain oil path to adjust the pilot pressure to be less than the target pilot pressure when a condition is satisfied.

Flow Control Valve

A main valve throttle () of a main valve () is configured by a lateral hole (A) communicating an inlet side flow passage () and an outlet side flow passage () through the inside of the main valve () and a groove portion (C) communicating the inlet side flow passage () and the outlet side flow passage () via an outer peripheral portion of the main valve (). The groove portion (C) is located such that a hydraulic fluid spurting from the groove portion (C) changes the direction of a flow of a hydraulic fluid spurting from the lateral hole (A). In this case, the direction of a flow of a hydraulic fluid F spurting from the lateral hole (A) can be changed to approach the direction parallel to the center axis of the main valve () by a hydraulic fluid F spurting from the groove portion (C). 1. A flow control valve comprising:a housing;a pilot housing;a main valve chamber provided in the housing;a main valve slidably provided in the main valve chamber and having a valve portion;a main valve seat provided on one end side of the main valve chamber and communicating or shutting off hydraulic fluid by allowing the valve portion of the main valve to be separated from and seated on the main valve seat;an inlet side flow passage providing pressure in the direction away from the main valve seat for the main valve and introducing hydraulic fluid from the outside of the main valve chamber to the inside of the main valve chamber;an outlet side flow passage introducing hydraulic fluid from the inside of the main valve chamber to the outside of the main valve chamber when the main valve is separated from the main valve seat and providing pressure in the direction away from the main valve seat for the main valve;a back pressure chamber provided on other end side of the main valve chamber and providing pressure in the direction coming closer to the main valve seat for the main valve;a feedback flow passage provided in the main valve and communicating the inlet side flow passage and the ...

Hydraulic valve and system

An apparatus includes a hydraulic circuit that is configured to selectively open fluid communication between one portion of the hydraulic circuit and another portion of the hydraulic circuit, such as a reservoir, based on the flow of the hydraulic fluid in the one portion. When the flow of hydraulic fluid exceeds a selected threshold in the one portion of the hydraulic circuit, the flow of fluid urges the opening of a hydraulic component of the hydraulic circuit to allow fluid communication between the one portion and the reservoir to discharge fluid from the one portion.

Hydraulic system for construction machinery

Disclosed is a hydraulic system for performing land preparation works by means of a simultaneous boom-up and arm-in operation. The hydraulic system according to the present invention includes: an arm cylinder and a boom cylinder that are connected to first and second hydraulic pumps, respectively; a first boom control valve that is disposed in the discharge flow path of the second hydraulic pump; a second boom control valve that is disposed in the discharge flow path of the first hydraulic pump and causes the working fluid of the first hydraulic pump to converge with the working fluid which is supplied from the second hydraulic pump to the boom cylinder; a first arm control valve that is disposed in the discharge flow path of the first hydraulic pump; a second arm control valve that is disposed in the discharge flow path of the second hydraulic pump and causes the working fluid of the second hydraulic pump to converge with the working fluid which is supplied from the first hydraulic pump to the arm cylinder; a recycle valve that is disposed in the flow path between the working fluid inlet port of the first arm control valve and a hydraulic tank; and a second boom control valve spool having a parallel pressure section in which the boom-up pilot pressure does not increase with respect to the boom-up strokes during the simultaneous boom-up and arm-in operation.

Slewing type construction machine

Provided is a slewing type construction machine including an upper slewing body and a slewing speed sensor that detects a slewing speed of the upper slewing body, enabling accurate control to be achieved regardless of an error in output from the slewing speed sensor. The construction machine includes an upper slewing body, a slewing motor, a hydraulic pump, a control valve, a slewing operation device, a slewing brake, a slewing speed sensor, a slewing operation detector that detects an operation applied to the slewing operation device, and a controller. The controller stores, during a slewing operation, a slewing speed detected by the slewing speed sensor at set time intervals, actuates the slewing brake based on a neutral return operation of the slewing operation device, and resets a stored value of the slewing speed that is stored during actuation of the slewing brake, to zero.

Working machine

A working machine includes a lower body, a turning body, a turning manipulating member which turns the turning body, a hydraulic motor which rotationally drives the turning body, a brake device which brakes the hydraulic motor, amain hydraulic source which supplies hydraulic oil to the hydraulic motor, and a direction control valve which controls a flow direction of the hydraulic oil according to the manipulated variable of the turning manipulating member, in which in a state where the hydraulic motor is braked by the brake device based on a manipulation of a brake manipulating member, when the turning manipulation is performed by the turning manipulating member, a brake applied to the hydraulic motor by the brake device is released with respect to turning in an indication direction indicated by the turning manipulation such that the turning body turns in the indication direction.

Proportional auxiliary flow adjustment system and method

An auxiliary flow adjustment system and method are disclosed for controlling an auxiliary hydraulic function on a machine in accordance with commands from an operator. The auxiliary flow adjustment system includes operator controls that control a hydraulic control valve. The control valve controls flow rate and flow direction to the auxiliary hydraulic function. When the auxiliary flow adjustment system is activated, the operator can use the operator controls to select a desired flow rate and flow direction for the auxiliary function and maintain the desired flow rate and direction without further use of the operator controls. When the flow adjustment system is activated while a non-zero flow rate is selected, the desired flow rate and direction can be set to the current settings. A resume control can retrieve and command the previously stored desired flow rate and direction. Controls can be used to increase and decrease the set flow rate.

Working Machine

Provided is a working machine capable of regenerating and utilizing surplus energy. The working machine related to the present invention is provided with a branching flow path ( 150 ) through which hydraulic oil flows between a hydraulic actuator ( 24 ) and a hydraulic pump-motor ( 14 ), an accumulator ( 30 ) arranged in the branching flow path, a first opening/closing valve ( 31 ) arranged between the accumulator and the hydraulic pump-motor, and a second opening/closing valve ( 32 ) arranged between the accumulator and the hydraulic actuator. A control device ( 41 ) selectively introduces the hydraulic oil from the hydraulic actuator and the hydraulic oil from the hydraulic pump-motor to the accumulator and accumulates the same by controlling opening/closing of the first opening/closing valve and the second opening/closing valve.

Servohydraulic Drive

A servohydraulic drive includes a hydrostatic displacement machine, an electric machine that is mechanically speed-coupled with the displacement machine, a hydraulic cylinder that is fluidically connected to the displacement machine via first and second working lines, a hydraulic accumulator, and a supply unit. The displacement machine has a stroke that is adjustable via a hydraulic adjustment device. The cylinder is configured to be activated by reversal of the fluid flow through the displacement machine in opposite directions. The accumulator is preset to a low pressure and is fluidically connected via a valve assembly in each case to the lower pressure working line. The supply unit is configured to supply the adjustment device with pressurized fluid under the necessary pressure for the adjustment regardless of the present pressure in the working lines such that the displacement machine is configured for an active and load pressure-independent adjustment of its stroke volume. 1. A servohydraulic drive , comprising:a hydrostatic displacement machine having a stroke volume configured to be adjusted by a hydraulic adjustment device;an electric machine that is mechanically speed-coupled with the displacement machine;a hydraulic cylinder that is fluidically connected to the displacement machine via a first working line and a second working line, the hydraulic cylinder configured to be activated by reversal of the fluid flow through the displacement machine in opposite directions;a low-pressure hydraulic accumulator that is preset to a low pressure and fluidically connected via a valve assembly in each case to one of the first and second working lines in which the lower pressure prevails; anda supply unit configured to supply the adjustment device with pressurized fluid under the necessary actuating pressure for the adjustment regardless of the present pressure in the first and second working lines.2. The servohydraulic drive according to claim 1 , further comprising a ...

FLOW VALVE CONTROL METHOD AND APPARATUS, AND STORAGE MEDIUM

A flow valve control method, apparatus, and storage medium are provided. The method comprises: conducting a median current value teach-in of a flow valve starting from an initial median current value of the flow valve; and correcting a flow-current curve of the flow valve based on a deviation value obtained by the teach-in. Each teach-in process comprises: controlling current output to a flow valve, so that the flow valve successively goes through: when there is a flow passing through, an output flow enables a shifting mechanism to return to position, and when there is a flow passing through again, an output flow again enables the shifting mechanism to return to position; recording a current value the twice when there is a flow passing through the flow valve as a maximum median current value; and acquiring a deviation value of the maximum median current value from the initial median current value. 1. A flow valve control method , wherein the method comprising:conducting a median current value teach-in of a flow valve starting from an initial median current value of the flow valve, wherein each process of teach-in comprises:controlling a current output to the flow valve, so that the flow valve goes through the following processes successively: a flow passes for the first time, the output flow makes a shifting mechanism return, a flow passes again, and the output flow makes the shifting mechanism return again;recording current values when the flows pass through the flow valve twice as the maximum median current values; andacquiring a deviation value of each of the maximum median current values and the initial median current value; andcorrecting a flow-current curve of the flow valve based on the deviation value,wherein an initial median current value in a first teach-in process is an default median current value, and an initial median current value in a next teach-in process is a corresponding median current value of the flow valve in the flow-current curve obtained ...

HYDRAULIC DRIVE WITH RAPID STROKE AND LOAD STROKE

A hydraulic drive including at least one hydraulic cylinder that includes a piston chamber, an annulus, and a piston that separates the piston chamber from the annulus. The hydraulic drive also includes a first hydraulic pump hydraulically connected with the piston chamber, a second hydraulic pump hydraulically connected with the annulus, a third hydraulic pump, and a directional control valve that has a first switching position and a second switching position. The third hydraulic pump in the first switching position of the directional control valve is hydraulically connected with the piston chamber, and the third hydraulic pump in the second switching position of the directional control valve is not hydraulically connected with the piston chamber. 1. A hydraulic drive for a hydraulic press , said hydraulic drive comprising: a piston chamber and an annulus; and', 'a piston that separates said piston chamber from said annulus;, 'at least one hydraulic cylinder, includinga first hydraulic pump hydraulically connected with said piston chamber and having a direction of fluid delivery;a second hydraulic pump hydraulically connected with said annulus and having a direction of fluid delivery;a third hydraulic pump having a direction of fluid delivery that is consistent with said direction of fluid delivery of the first hydraulic pump; anda directional control valve that has a first switching position and a second switching position, wherein said third hydraulic pump in said first switching position of the directional control valve is hydraulically connected with said piston chamber and wherein said third hydraulic pump in said second switching position of the directional control valve is not hydraulically connected with said piston chamber, wherein said directional control valve is hydraulically controllable in such a way that a pressure in said piston chamber is used for shifting said directional control valve from the first switching position into the second switching ...

Discrete Pilot Stage Valve Arrangement With Fail Freeze Mode

An on-off pilot stage valve arrangement for controlling at least one main stage valve. The on-off pilot stage valve arrangement includes a first pilot valve discretely operable between two states, an on and an off state, the first pilot valve having an input at which there is a first pressure and an output connected to the main stage valve, a second pilot valve discretely operable between two states, an on and an off state, the second pilot stage valve having an input at which there is a second pressure and an output connected to the main stage valve. Both the valves are configured to be set in one of the two states in case the arrangement loses power.

Hydraulic system, mining machine and method of controlling hydraulic actuator

A hydraulic system, mining machine and method of controlling a hydraulic actuator. The hydraulic system (HS) is provided with a control valve (23) for controlling movement direction and speed of a hydraulic actuator (HA) connected to the system. Generated force of the hydraulic actuator is controlled independently relative to the control valve by means of counterbalance valves (Cb1, Cb2) and servo valves (Sv1, Sv2) controlling their opening pressure. The counterbalance valves and the servo valves operate as a meter-out control assembly which controls flow of hydraulic fluid discharged from working pressure spaces (16a, 16b) of the hydraulic actuator. The disclosed system may be implemented to control a mining boom (3) of a mining machine (1).

Hydraulic system of construction machine

A hydraulic system of a construction machine includes: control valves interposed between a variable displacement main pump and hydraulic actuators; and first solenoid proportional valves connected to pilot ports of the control valves. The hydraulic system further includes: a regulator that changes a displacement of the main pump; and a second solenoid proportional valve connected to an auxiliary pump by a primary pressure line, the second solenoid proportional valve outputting a secondary pressure to the regulator through a secondary pressure line. A switching valve is interposed between the auxiliary pump and the first solenoid proportional valves, and includes a pilot port that is connected to the secondary pressure line by a pilot line.

HORIZONTAL STABILIZER TRIM ACTUATOR SYSTEMS AND METHODS

Systems and methods are provided for a hydraulic stabilizer trim actuator (HSTA). The HSTA may operate one or more movable control surfaces. The HSTA operate responsive to commands issued by the pilot and/or by a controller and may include hydraulic architecture that minimizes the probability of an un-commanded movement or movement in the opposite direction of such commands 1. A system comprising:a hydraulic inlet configured to receive pressurized hydraulic fluid;a first hydraulic path fluidically connected to the hydraulic inlet;a second hydraulic path;a hydraulic shutoff apparatus fluidically connected to the first hydraulic path and the second hydraulic path and configured to be switched between a plurality of hydraulic positions, wherein at least one of the hydraulic positions allows for the pressurized hydraulic fluid to flow from the first hydraulic path through the hydraulic shutoff apparatus to the second hydraulic path;a directional and rate control apparatus;a third hydraulic path fluidically connected to the directional and rate control apparatus; and the directional and rate control apparatus is configured to be switched between a plurality of directional control positions wherein at least one of the directional control positions allows for the pressurized hydraulic fluid to flow from the second hydraulic path through the directional and rate control apparatus to the hydraulic motor;', 'the hydraulic motor is configured to turn an output shaft to actuate a control surface of a vehicle responsive to receiving the pressurized hydraulic fluid from the directional and rate control apparatus and configured to be locked responsive to not receiving the pressurized hydraulic fluid from the directional and rate control apparatus; and, 'a hydraulic motor fluidically connected to the directional and rate control apparatus via the third hydraulic path, whereina brake apparatus connected to the hydraulic motor and/or the output shaft.2. The system of claim 1 , ...

Latch Pin Assembly

A folding wing tip system of an aircraft includes a latch pin actuator having a primary mechanical lock and a secondary hydraulic lock. The mechanical lock may include a lock cam movable between a lock position, in which the lock cam engages the latch pin, and an unlock position, in which the lock cam is disengaged from the latch pin, and a first lock actuator mechanically coupled to the lock cam and configured to provide a bias force pushing the lock cam toward the lock position. The hydraulic lock may be disposed in an unlatching hydraulic line and has an initial state, in which fluid flow through the unlatching hydraulic line is blocked thereby to hold the latch pin in the latched position, and an open state, in which fluid flow through the unlatching hydraulic line is permitted thereby to permit retraction of the latch pin to the unlatched position. 1. A latch pin assembly for use with a hydraulic fluid source , the latch pin assembly comprising:a latch pin defining an extend chamber and a retract chamber, the latch pin including a latch surface;a latching hydraulic line fluidly communicating between the extend chamber and the hydraulic fluid source;an unlatching hydraulic line fluidly communicating between the retract chamber and the hydraulic fluid source;a mechanical lock engaging the latch surface of the latch pin when in a lock position to mechanically lock the latch pin in a latched position; anda hydraulic lock disposed in the latching hydraulic line and having an initial state, in which fluid flow is blocked from exiting the extend chamber through the latching hydraulic line, and an open state, in which fluid flow is permitted from the extend chamber through the latching hydraulic line.2. The latch pin assembly of claim 1 , in which the mechanical lock comprises:a lock cam movable between a lock position, in which the lock cam engages the latch surface of the latch pin, and an unlock position, in which the lock cam is disengaged from the latch surface of ...

Hydraulic actuator

A hydraulic actuator includes a switching part that is provided with an oil passage for sending pressurized oil generated by a hydraulic pump to a tool and returning return oil from the tool to the hydraulic pump. The switching part switches a route of at least one of the pressurized oil and the return oil. The switching part includes an operating portion (for example, an operation knob) and an axis portion (for example, a spool) that advances or retreats when the operating portion is turned. When the operating portion is turned, the axis portion advances or retreats in a direction orthogonal to a direction of turning the operating portion, whereby the route of the oil passage is switched.

SYSTEMS AND METHODS FOR SELECTIVELY ENGAGED REGENERATION OF A HYDRAULIC SYSTEM

A hydraulic system and method for using the same are provided. The hydraulic system includes a pump, a first actuator having a first head chamber and a first rod chamber, and a second actuator having a second head chamber and a second rod chamber. The hydraulic system further includes a first control valve and a second control valve. The second control valve to selectively provide regeneration fluid flow from the first rod chamber to the first head chamber in response to a first function command is less than a first function command limit, a second function command is greater than a second function command limit, and a second function load is greater than a second function load limit. 1. A control valve assembly for a hydraulic system , the hydraulic system including a first function operated by a first actuator , a second function operated by a second actuator , and a pump to furnish fluid from a reservoir to a supply conduit , the first actuator including a first head chamber and a first rod chamber and the second actuator including a second head chamber and a second rod chamber , the control valve assembly comprising:a first control valve to selectively provide fluid communication between the first actuator and both the supply conduit and the reservoir in response to a first function command;a second control valve to selectively provide fluid communication between the first actuator and both the supply conduit and the reservoir in response to the first function command;the second control valve to selectively provide regeneration fluid flow from the first rod chamber to the first head chamber when a first function command is less than a first function command limit, a second function command is greater than a second function command limit, and a second function load is greater than a second function load limit.2. The control valve assembly of claim 1 , further comprising a third control valve to selectively provide fluid communication between the second actuator ...

HYDRAULIC DRIVE SYSTEM FOR CONSTRUCTION MACHINE

Pressure compensating valves not fully closing at the stroke end are employed, and upon the operator's operation for the traveling, pilot primary pressure is reduced and supplied to remote control valves -of non-travel operating devices. Thus, the inflow of the hydraulic fluid into non-travel actuators is suppressed and a necessary amount of hydraulic fluid for travel motors is secured in travel combined operation. Accordingly, when saturation occurs in a construction machine's hydraulic drive system performing the load sensing control due to combined operation with a great load pressure difference between two actuators, deceleration/stoppage of an actuator on the low load pressure side is prevented by preventing full closure of the pressure compensating valve on the low load pressure side, while also preventing deceleration/stoppage of a high load pressure actuator by securing a necessary amount of hydraulic fluid for the high load pressure actuator. 1. A hydraulic drive system for a construction machine , comprising:a variable displacement type hydraulic pump;a plurality of actuators which are driven by hydraulic fluid delivered from the hydraulic pump;a plurality of flow control valves which respectively control flow rates of the hydraulic fluid supplied from the hydraulic pump to the actuators;a plurality of operating devices corresponding respectively to the actuators, each of the operating devices includes a remote control valve for generating operation pilot pressures for driving the corresponding flow control valve;a plurality of pressure compensating valves which are connected to a supply line of the hydraulic pump and which respectively control differential pressures across the flow control valves;a pilot primary pressure circuit which supplies, as pilot primary pressure, a pressure of a pilot hydraulic pressure source to the remote control valves of the operating devices; anda pump control system which performs load sensing control of a displacement of ...

HYDRAULIC SYSTEM AND METHOD FOR REDUCING BOOM BOUNCE WITH COUNTER-BALANCE PROTECTION

A hydraulic system () and method for reducing boom dynamics of a boom (), while providing counter-balance valve protection, includes a hydraulic cylinder (), first and second counter-balance valves (), first and second control valves (), and a selection valve set (). The selection valve set is adapted to self-configure to a first configuration and to a second configuration when a net load () is supported by a first chamber () and a second chamber () of the hydraulic cylinder, respectively. When the selection valve set is enabled in the first and second configurations, the second and first control valve may fluctuate hydraulic fluid flow to the second and first chamber, respectively, to produce a vibratory response () that counters environmental vibrations () of the boom. When the selection valve set is not enabled, the first and second counter-balance valves are adapted to provide the hydraulic cylinder with conventional counter-balance valve protection. 1. (canceled)2. A hydraulic system for actuating a boom , the hydraulic system comprising:a hydraulic actuator including a first chamber and a second chamber;a first control valve fluidly connected to the first chamber via a first counter-balance valve;a second control valve fluidly connected to the second chamber via a second counter-balance valve, the first and second control valves being independently operable with respect to each other; anda controller that interfaces with the first and second control valves, wherein the controller is configured to generate a vibration control signal that is transmitted to at least one of the first and second control valves to produce a vibratory control response applied to at least one of the first and second chambers.3. The hydraulic system of claim 2 , wherein the boom includes at least three arms that are pivotally connected to one another.4. The hydraulic system of claim 2 , wherein the boom is a concrete placement boom.5. The hydraulic system of claim 2 , wherein the ...

Spool valve and hydraulic apparatus including the same

A spool valve is provided. A valve housing has a pilot fluid passage, and a first portion and a second portion lengthwisely spaced apart from each other. A spool is movably inserted in the valve housing, and includes a plug able to enter the pilot fluid passage between the first portion and the second portion to change a flow area of the pilot fluid passage following movement of the spool. A hydraulic machine provides that when pilot fluid is supplied to the pilot fluid passage through the first portion, at least a portion of the supplied pilot fluid is provided to the holding valve through the second portion. The holding valve allows a flow of working fluid from the first chamber to the spool valve, and the spool moves to a third position to forward working fluid to the second chamber.

LARGE MANIPULATOR WITH DECENTRALIZED HYDRAULIC SYSTEM

A manipulator includes an articulated boom configured to be folded out. The articulated boom includes a turntable that can be rotated about a vertical axis, a plurality of boom segments, electrically-actuated proportional valves, and a remote control. The boom segments are pivotable via respective drive assemblies. The electrically-actuated proportional valves are respectively arranged directly on or in proximity to the respective drive assemblies to be controlled. The remote control includes at least one control lever configured to be displaced in a plurality of actuating directions. The manipulator further includes an electronic controller configured to actuate the drive assemblies via a travel command. The travel command indicates a desired movement of the boom tip. The travel command is generated in response to displacement of the control lever into at least one of the plurality of actuating directions. And, the travel command causes actuation of the respective electrically-actuated proportional valves. 19-. (canceled)10. A manipulator comprising: a turntable that can be rotated about a vertical axis,', 'a plurality of boom segments, the boom segments are pivotable about respective articulation axes at articulation joints relative to an adjacent boom segment or relative to the turntable via respective drive assemblies, the drive assemblies each coupled to hydraulic control lines, wherein a last of the boom segments of the plurality of boom segments includes a boom tip, and', 'electrically-actuated proportional valves respectively arranged directly on or in proximity to the respective drive assemblies to be controlled and respectively coupled to the hydraulic control lines of the respective drive assembly;, 'an articulated boom configured to be folded out and includinga remote control having at least one control lever, the control lever configured to be displaced in a plurality of actuating directions; andan electronic controller configured to actuate the drive ...

LOAD SENSING ELECTRIC-PROPORTIONAL MULTI-WAY VALVE

This application discloses a load sensing electric-proportional multi-way valve. The technical problem to be solved by the present application is to provide a load sensing electric-proportional multi-way valve, enabling individual loops to operate with different loads, to save energy and reduce the environmental pollution. The technical solution for solving the technical issue includes as follows. A load sensing electric-proportional multi-way valve includes a main oil passage connected with two gear pumps P and P, a lifting loop connecting to the main oil passage via an electric-proportional pressure compensated flow control valve, and an inclining union and an attachment union connecting to the main oil passage via an electric-proportional pressure compensated flow control valve, a logic direction valve connected to the main oil passage, a proportional motor-driven overflow valve and a two-way solenoid valve connecting to an oil inlet port of the logic direction valve. 1112. A load sensing electric-proportional multi-way valve , comprising a dynamic load sensing pressure compensation valve , a safety valve I and a pressure compensated flow regulating valve I , wherein the dynamic load sensing pressure compensation valve has an oil inlet port connecting a gear pump P , an oil outlet port connecting a port CF of a redirector , and another oil outlet port connecting a main oil passage of the multi-way valve , and a signal oil port LS of the compensation valve is connected with both a port LS of the redirector and an oil inlet port of the safety valve I , and an oil outlet port of the safety valve I is connected with an oil return port D; the main oil passage , in one aspect , is connected sequentially with a lifting loop and a hydraulic one-way valve I , with an outlet port of the hydraulic one-way valve I being respectively connected with a lifting oil port A and a lowering loop in which an oil outlet port is connected with an oil return port T , the main oil ...

Controlled three-way proportional valve unit

The invention relates to a controlled three-way proportional valve unit comprising: a valve assembly with two individual valves; an actuating device actuating valves of the valve assembly; and a control unit acting upon the actuating device and having a control signal input, the valves of the valve assembly being designed as poppet valves arranged on opposite sides and having counter-rotatable valve spindles. The valve spindles are prestressed relative each other in opposite directions by a prestressing element such that, when the actuating unit is inactive, a first poppet valve is open and the second poppet valve is closed. The actuating device comprises an actuator common to both poppet valves, acts upon the two valve spindles and changes the position of the valve spindles counter to the effect of the prestressing element.

Electrohydraulic implement pressure cutoff

An electrohydraulic implement pressure cutoff system is disclosed that includes a pump, one or more hydraulic functions, at least one valve, sensors and control unit. The pump powers the functions, and the valves control flow between the pump and their associated function. The sensor readings indicate system parameters. The control unit receives the readings and controls the valves. When the readings indicate a function is at or beyond a threshold, the control unit closes the associated valve to prevent flow to or from that function. The sensors can be pressure, position or other types of sensors. Operator control signals can be provided to control the functions. When the readings indicate a function is at or beyond a threshold in a stalled direction and the operator signals keep commanding the function in the stalled direction, the control unit can close the associated valve regardless of the operator signals.

Valve

The invention relates to a valve ( 10, 50, 52 ) for operating a pressurizing medium driven actuator of a process control valve for technical process equipment, comprising a valve seat ( 14 ) in a basic valve body ( 48 ), a closing body ( 12 ) and an electromagnetic drive ( 18, 30 ), which closing body ( 12 ) is ball-shaped and cooperates with a valve seat ( 14 ) so as to block the flow from an inlet side to an outlet side, said closing body ( 12 ) cooperating with a piston surface ( 20 ) which can be moved within a piston chamber ( 25 ) connected to the inlet side, characterized in that a connecting element ( 17 ) is provided between the closing body ( 12 ) and the piston surface ( 20 ) which is actively connected to an armature ( 18 ) of an electromagnetic linear direct drive, with a coil assembly ( 30 ) being embedded in the basic valve body ( 28 ) and a magnetic field with alternating polarity in the axial direction being present at the armature ( 18 ).

DYNAMIC OPEN CENTER HYDRAULIC SYSTEM CONTROL

The present invention relates to a hydraulic valve control unit for an open center hydraulic system, the open center hydraulic system comprising a pump, a shunt valve and one or more actuator valves coupled to the shunt valve, wherein each actuator valve is controlling a corresponding actuator's position, the hydraulic valve control unit comprising a processor and a memory, said memory containing instructions executable by said processor, wherein said hydraulic valve control unit is configured to obtain user input data indicative of at least a desired actuator's position, determining opening area values of the one or more actuator valves using a predetermined relation dependent on the user input data, determining an opening area value of the shunt valve using the predetermined relation dependent on the user input data, controlling the shunt valve based on the opening area value of the shunt valve, and controlling the one or more actuator valves based on the opening area values of the one or more actuator valves. The invention further relates to an open center hydraulic system. 1200100100121130141143130. A hydraulic valve control unit () for an open center hydraulic system () , the open center hydraulic system () comprising a pump () , a shunt valve () and one or more actuator valves (-) coupled to the shunt valve () ,{'b': 141', '143', '151', '153', '200, "wherein each actuator valve (-) is controlling a corresponding actuator's (-) position, the hydraulic valve control unit () comprising:"}{'b': '212', 'a processor () and'}{'b': '215', 'a memory (), said memory containing instructions executable by said processor,'}{'b': '200', 'wherein said hydraulic valve control unit () is configured to{'b': 151', '153, "obtain user input data indicative of at least a desired actuator's (-) position,"}{'b': 141', '143, 'determine opening area values of the one or more actuator valves (-) using a predetermined relation dependent on the user input data,'}{'b': '130', 'determine an ...

Flow Control Valve with Load-Sense Signal Generation

An example valve includes a first port fluidly coupled to a source of fluid, a second port fluidly coupled to an actuator, a third port fluidly coupled to a reservoir, and a fourth port configured to export a load-sense (LS) fluid signal. The valve can operate in: a neutral state, wherein fluid is allowed to flow from the second port to the third port, while the first port and the fourth port are blocked; a first actuated state, wherein fluid flow is throttled from the second port to the third port, while the first port and the fourth port remain blocked; or a second actuated state, wherein fluid flow from the second port to the third port is blocked, while fluid flow is allowed from the first port to the second port and from the second port to the fourth port. 1. A valve comprising:a plurality of ports comprising: (i) a first port configured to be fluidly coupled to a source of fluid, (ii) a second port configured to be fluidly coupled to an actuator, (iii) a third port configured to be fluidly coupled to a reservoir, and (iv) a fourth port configured to export a load-sense (LS) fluid signal from the valve;a main spool having (i) a distal end configured to be subjected to a first fluid force applied by fluid from the first port, and (ii) a proximal end; andat least one spring configured to apply a biasing force on the main spool, wherein the at least one spring is disposed in a spring chamber, wherein the proximal end of the main spool is configured to be subjected to a second fluid force applied by fluid in the spring chamber, such that an axial position of the main spool is determined by a force balance between the first fluid force, the second fluid force, and the biasing force,wherein the valve is configured to operate in one of three states: (i) a neutral state, wherein the main spool allows fluid flow from the second port to the third port, while the first port and the fourth port are blocked, (ii) a first actuated state, wherein the main spool moves to a ...

Hydraulic drive system for operation table

A hydraulic drive system includes an oil supply device, an oil return device and a hydraulic cylinder circuit component. The circuit component includes a hydraulic cylinder, a first and a second two-position two-way electromagnetic directional valves. The cylinder includes a first chamber and a second chamber that has a piston rod. A first port of the first valve connects with the first chamber and a first port of the second valve connects with the second chamber. When the oil supply device connects to a second port of the first valve and a second port of the second valve connects to the oil return device, the piston rod is extended outwards. When the oil supply device connects to the second port of the second valve and the second port of the first valve connects to the oil return device, the piston rod is retracted.

Servo-control and an aircraft having such a servo-control

A servo-control having at least one movable cylinder that includes a hydraulic directional control valve. The hydraulic valve includes a control shaft that is rotatable about a longitudinal axis, the control shaft being connected to a distributor slide. The servo-control including a stationary abutment member secured to a cylinder and an input lever situated outside the cylinder. The input lever is connected to the control shaft and includes a stop portion arranged in the abutment member. The servo-control includes movement means for moving the input lever longitudinally, a first abutment surface of the abutment member limiting a travel amplitude of the stop portion when the input lever is in a first position.

System for controlling the supply of hydraulic fluid to a work vehicle implement

In one aspect, a system for controlling the supply of hydraulic fluid to an implement of a work vehicle may generally include a pump, a control valve coupled to the pump and first and second fluid lines provided in flow communication with output ports of the control valve. The system may also include a pressure control valve provided in flow communication with the second fluid line that is configured to regulate a fluid pressure of the hydraulic fluid being supplied to a hydraulic cylinder of the implement. Additionally, the system may include a bypass fluid line configured to provide a flow path for hydraulic fluid between the pump and the second fluid line that is independent of the control valve and a load sensing line configured to provide an indication of the fluid pressure of the hydraulic fluid being supplied to the hydraulic cylinder.

Hydraulic control apparatus

A hydraulic control apparatus includes an output-side oil passage into which oil from a first oil passage and oil from a second oil passage flow, and a pressure regulating check valve regulating a hydraulic pressure in the second oil passage. The pressure regulating check valve includes first and second elastic portions housed in a spool hole between a valve body and a bottom of the spool hole. A natural length of the second elastic portion is shorter than a distance between the valve body and the bottom when the valve body closes an inflow hole. The second elastic portion applies an elastic force to the valve body in a state in which the valve body opens the inflow hole.

PNEUMATIC VALVE DRIVE

A pneumatic valve drive () for a valve (), in particular for a vacuum valve, which has at least one pneumatic cylinder () with at least one piston () that is movably mounted in the pneumatic cylinder () and at least two cylinder cavities () arranged on opposite sides of the piston (). Each cylinder cavity () is connected to at least one pressure source for applying pressure to each cylinder cavity (). One of the pressure sources is a constant pressure source () for applying a constant pressure to the cylinder cavity () arranged on one of the sides of the piston, and one of the other pressure sources is a regulated pressure source () for applying a variably regulatable pressure to the cylinder cavity () arranged on the opposite side of the piston (). 1. A pneumatic valve drive for a valve , comprising a pneumatic cylinder having at least one piston that is mounted so as to be displaceable in the pneumatic cylinder , and having at least two cylinder cavities that are disposed at mutually opposite sides of the piston , each of the cylinder cavities is connected in each case to at least one pressure source in order for the respective cylinder cavity to be impinged with pressure , one of the pressure sources is a constant pressure source for impinging the cylinder cavity that is disposed on one of the sides of the piston with a constant pressure , and another of the pressure sources is a regulated pressure source for impinging the cylinder cavity that is disposed on an opposite side of the piston with a variably regulatable pressure.2. The pneumatic valve drive as claimed in claim 1 , further comprising a regulator having a position-determining arrangement for determining a position of the piston relative to the pneumatic cylinder claim 1 , and the regulator regulates the regulated pressure source in a manner dependent on said position.3. The pneumatic valve drive as claimed in claim 1 , further comprising at least one system pressure input.4. The pneumatic valve drive ...

Engine-driven oil pump

An engine-driven oil pump has an engine, a pump unit, an oil diverting device, a manual control unit, and a remote control unit. The engine is connected to the pump unit. The oil diverting device is mounted on the pump unit and selectively pumps hydraulic oil from the pump unit into the manual control unit or the remote control unit. With the engine, the engine-driven oil pump can generate power independently instead of relying on external power supply. Besides, the electromagnetic valve of the remote control unit allows the user to remotely control the oil path of the hydraulic oil, so the user is not required to stay along the engine-driven oil pump to manually switch the oil path, and therefore the engine-driven oil pump is more efficient regarding manpower.

Control system for hybrid construction machine

A control system for a hybrid construction machine includes first and second main pumps for supplying working oil, a boom cylinder extending by supply of the working oil to a piston-side chamber and raising a boom and contracting by discharge of the working oil from the piston-side chamber and lowering the boom, a regenerative spool valve controlled by a pressure of pilot pressure oil and adjusting a flow rate of the working oil discharged from the piston-side chamber, a regenerative motor for regeneration rotating by the working oil discharged from the piston-side chamber, a rotary electric machine connected to the regenerative motor, and a failsafe switching valve switching with a pressure of a regenerative passage between the regenerative control spool valve and the regenerative motor as a pilot pressure and lowering the pressure of the pilot pressure oil to the regenerative control spool valve so that a flow rate of the working oil discharged from the piston-side chamber is narrowed if the pressure of the regenerative passage is less than a set pressure.

Linear Actuator Assembly and System

A linear actuator system includes a linear actuator and at least one proportional control valve and at least one pump connected to the linear actuator to provide fluid to operate the linear actuator. The at least one pump includes at least one fluid driver having a prime mover and a fluid displacement assembly to be driven by the prime mover such that fluid is transferred from the pump inlet to the pump outlet. The linear actuator system also includes a controller that establishes at least one of a speed and a torque of the at least one prime mover and concurrently establishes an opening of the at least one proportional control valve to adjust at least one of a flow and a pressure in the linear actuator system to an operational set point.

Fluid pressure control device

A fluid pressure control device includes a switching valve, a main pilot passage and a sub pilot passage, the switching valve is configured to be switched to the communication position when the working fluid is supplied to the pilot chamber, and to be switched to the shut-off position with opening on the downstream side of the switching valve in the neutral passage, and the switching valve has a throttle portion configured to throttle the flow of the working fluid in the neutral passage at the communication position.