MAGNETIC FORCE SENSOR

The invention relates to a method of measuring forces acting on a component by at least one magnetic force sensor, a magnetic track having at least one of soft magnetic material, and at least one magnetic track having at least one interruption with a distance, wherein a magnetic flux induced in the at least one magnetic strip conductor being permanently, a magnetic force sensor for carrying out this method and a method of manufacturing this magnetic force sensor.

The measurement of physical quantities on components of driving - and aircraft for example, machines or buildings is a key point in their maintenance and condition monitoring. An important size force acting on a component, whose measurement on the total state of the component is the load or important information provides this.

Currently the most widely used method is the measurement of the deformations and forces occurring here by means of strain gauges, which are mounted on respective points of the member. A considerable disadvantage of this system lies, strain gauges are bonded to the component to be measured that, said bonding affects the transmission of the measurement information and possibly distorted. Further the strain gauge must be contacted electrically, in order to read measurement information, wherein it is necessary in the case of metallic components, the electrical measuring circuit to isolate completely from the component.

It methods are therefore become known, in which the measurement of deformations is a component on magnetic path.

De 10 2014, 200, 461 describes a device for measuring such a force or a torque AI on a machine element having a permanent magnetization along a closed path magnetization.

In this case a magnetic field sensor is provided, which monitors a change in the magnetic field. This arrangement is not suitable for all components, as it requires a permanent magnetization of the component at least in a certain area. It is also susceptible to breakdown magnetic and/or electrical or electromagnetic to outside influences.

In DE 24,846 36 AI described a device for the contactless measuring a mechanical stress, in particular for measuring the torsional or bending force of an object. This two regions are arranged on a shaft with a layer of magneto-elastic material, at an angle of 45° formed having a stripe pattern. This layer a change pattern of the shaft by means of a complicated evaluation circuit is monitored when subjected to mechanical stress.

Another magnetoelastic torque sensor can also

The de 103 31,128 AI are removed.

The us 5,036,236 a is based on magnetic fields discloses a proximity sensor, wherein the sensor comprises a magnetic conductor with an interruption, which serves as a reference for the distance between two mutually moving components of magnetic material.

The above arrangements are for monitoring the deformation processes on a component only partially or not at all suitable, or have a complicated in practice little suitable structure.

It is therefore the task of the invention, to provide a method and a magnetic force sensor available, suitable for the monitoring of the deformation processes on a component also of non-magnetic material, wherein the sensor can be located at any desired points on the component to be monitored.

This problem is solved according to the invention characterized, in that the magnetic flux in the at least one magnetic track a change of the distance of the at least one magnetic track is monitored causes a change of the magnetic flux in the at least one magnetic track.

Wherein an optional deformation of the component to be monitored on the basis of the distance of the at least one interruption exerted forces the at least one magnetic track changes. So that the magnetic field induced in the interrupt of the at least one magnetic track, whereby the magnetic flux in the at least one magnetic track changes but again changes. This change of the magnetic flux is thus an indicator of a deformation of the component to be monitored.

Preferably is provided, in that the magnetic flux in the at least one conductor track is induced by at least one magnetic exciter, which is preferably in direct contact with the at least one magnetic track, . Alternatively the at least one exciter magnet can also be formed outside of the force sensor but, for example as part of the component to be monitored as an additional element in the area of the component to be monitored or.

In a further variant of the invention the measurement of the magnetic flux takes place inductively measurement method, according to the fluxgate principle, on the anisotropic magnetic resistance or the magneto-impedance.

The measurement of the flow alteration is performed inductively, can in this case be measured Flussänderungen so quickly, wherein this method is insensitive to slowly, gradually changes occurring. This method further can be determined not absolute magnetic flux values.

When the electrical resistance of a ferromagnetic material varies with anisotropic magnetorestistiven effect magnetization, wherein this change in resistance can be measured.

The magneto-impedance effect is based partly on the change in the differential permeability of a soft magnetic material according to its magnetization, and on the so-called skin effect, wherein the stream is pressed in a conductor at high frequencies by the own magnetic field surface. Together these effects causing, in that the alternating current resistance of a soft magnetic conductor is; this effect is heavily dependent on an external magnetic field for at frequencies in the MHz range particularly well observed.

Fluxgate sensors can measure precisely small magnetic fluxes, wherein this type of measurement is consuming, because the measuring sections that must be surrounded by coils.

Each of these measurement methods is suitable, detecting the change in distance to the at least one interruption in the at least one conductor track on the magnetic measuring circuit.

Preferably the measured value for the magnetic flux in an evaluation unit is compared to a prescribable threshold value, and output a signal when this threshold. This signal serves as a warning signal, if the component to be monitored deforms, whereby the change in distance at least an interrupt is caused in the magnetic track.

The force sensor is on a substrate according to the invention, preferably arranged directly on the component to be monitored, wherein a change of the distance of the interruption of the at least one magnetic track is monitored.

The invention in a first embodiment of the invention has a particularly simple force sensor structure and can be arranged on any ground.

According to the invention is provided, in a first embodiment of the invention is that the substrate made of an insulating material, for example plastic, ceramic, glass, sapphire or mica. The invention is applied on the substrate for example by galvanic deposition this force sensor on said substrate, which is in turn arranged on the component to be measured.

In a particularly preferred variant is alternatively provided, in that the force sensor is directly on the component, applied in particular by galvanic deposition. In this case can be provided, in that the force sensor has a magnetic barrier layer of non-magnetic material, to insulate the force sensor to a magnetizable member and thereby protect this invention to interference.

In the force sensor to produce a magnetic flux, at least one exciter magnet is provided according to the invention. This magnet can be a permanent magnet, is produced by galvanic deposition preferably also. For this purpose a hard magnetic alloy deposited will be permanently incorporated in a non-magnetic magnetic particles can also öderes array. Alternatively the exciter magnet can also be an electromagnet.

The invention preferably via at least one measuring device for monitoring the force sensor has magnetic flux within the at least one conductor track. In this way an integral measuring sensor is obtained, without any additional external measuring unit is required.

This is particularly preferably provided, the at least one measuring means measuring chip is formed with at least one, preferably two internal magnetic measuring sections, wherein the measuring chip is preferably arranged on an electrically insulating support, for example plastic, ceramic, glass, sapphire or mica. This measuring chip evaluates the changes of magnetic flow and passes on the data to an evaluation unit (external) obtained.

In a particularly preferred embodiment of the invention, the at least one magnetic track with the at least one interruption and the at least one measuring device form a magnetic measuring circuit.

Particularly preferably the at least one exciter magnet is also a part of this this magnetic measuring circuit. Alternatively positionable outside the at least one excitation magnetic force sensor.

In the accident-prone environments it may be necessary, or temperature fluctuations affect external effects such as stray fields, the magnetic flux of a force independently, to compensate for. For this purpose a second magnetic circuit, namely a magnetic compensation circuit is preferably provided with at least one further excitation magnet. The adaptation of the magnetic resistance of the magnetic conductor by influencing the permeability of the selectively compensation circuit during manufacture, namely the deposition for example be achieved by variation of the pulse pattern used for the deposition, by geometric variations as layer thickness and/or conductor width, by incorporating an additional interruption of the magnetic conductor of the compensation circuit to a suitable location or by a combination of these measures.

The at least one measuring device, in particular the measuring chip connects the two magnetic circuits, namely the at least one measuring circuit and said at least one compensation circuit preferably via a Wheatstone bridge. This structure smallest changes can be measured magnetic flux already exactly.

The invention is used in particular for the determination of deformations of components force sensor.

The preparing the force sensor by means of a manufacturing process, wherein on a substrate, preferably on a component to be monitored, at least one magnetic track having at least one interruption with a distance applied, wherein the application is particularly preferably by galvanic deposition.

This a soft magnetic alloy, for example a nickel-iron alloy is a galvanic applied with optimized composition to a preferably non-magnetic path, optionally masked component. This interruption is required for the measurement with a defined distance in the masking or applied either already is incorporated after coating with a laser for example.

The substrate is, is applied to said force sensor, magnetically, for example of steel or cast iron, so should be applied before applying the conductive tracks on the base material a nonmagnetic layer. This nonmagnetic layer is produced by electroplating a layer of copper also for example, tin, zinc or an alloy of two or more of these elements or a nonmagnetic alloy of ferrous metals but also with phosphorus. This fully metallic structure to obtain an optimum connection of the sensor to the component, for example without an additional adhesive layer for applying the sensor on the component to be measured can influence the measurement results.

The galvanic producing the excitation magnet, are particularly suitable for the invention the force sensor, can be realized in two different ways.

In a variant of a permanent magnetic alloy, which is selected from a group, alloys such as cobalt-nickel phosphorus containing, cobalt-nickel-manganese phosphorus, cobalt-nickel-rhenium phosphorus, iron-platinum, cobalt-platinum and bismuth-manganese is, galvanically deposited on the substrate member.

Alternatively be incorporated during the galvanic deposition on the substrate, in particular the component, into a non-magnetic, metallic matrix permanent magnetic micro-- or nanoparticles. In this all eligible hard magnetic materials as particles, as well as hard magnetic alloys in an appropriate manner, for example as a nanowire, as powder such as ferrites, chromium dioxide, iron oxide, neodymium-iron-boron powder or cobalt-samarium powder. These particles can either in pure form or chemical surface modification after suitable, for example with siloxanes are used. The chemical modification of the surface of the particles serves the control of the installation rate of the particles in the galvanic layer, on the other hand increased chemical stability can thus be used for the deposition against the electrolyte.

Preferably the permanent magnetic layer in a externally applied magnetic field was deposition, aligns the particles in their magnetization direction and so that the resulting field strength of the electrodeposited permanent magnet increases.

It is possible for special requirements, perform the deposition of the permanent magnet layer and to change the direction of the outer magnetic field in several phases between the phases. Permanent magnetic layers with locally varying magnetization can be generated thereby.

In the following the invention is explained in greater detail below with associated Figures not limiting embodiments. Herein show

A schematic view of a first embodiment of the invention 1 figfig. force sensor,

A detail view of the force sensor from the magnetic track 2 figfig. figfig. 1, 3 a detail view of the measuring chip from figfig. figfig. 1,

A schematic representation of the layer structure of the force sensor 4 from figfig.

1 Figfig., and

5 A schematic view of a second implementation of the invention figfig. force sensor.

In a first figfig. 1, particularly preferred implementation of the invention 100 force sensor is represented. This force sensor 100 has a magnetic measuring circuit 110 with a magnetic track 111, in which a first excitation magnetic 120 is arranged.

This magnetic strip conductor 110 has an interruption 130, wherein the two ends of the magnetic track are 112a, 112b is at a distance to one another their both ends 112a, 112b in its cross section (see, figfig. and 2) taper. By these top - or arrow-shaped configuration of the two ends 112a, 112b of the magnetic conductor track 111 particularly strong magnetic field lines are constructed in this area, whereby a more accurate measurement of the distance a of the two ends of an optional change 112a, 112b to each other and an optional change of the magnetic field between the two ends this will allow 112a, 112b.

To minimize influences, in particular magnetic and/or electromagnetic influences from the environment, the invention in this embodiment of the invention additionally has a compensation force sensor 100 measuring circuit 210 having a magnetic strip conductor 211, the also includes a second excitation magnet 220. The magnetic fluxes of the two magnetically effective measurement circuits 110, 210 are measured over a measuring chip 300 against each other.

This measuring chip 300 is shown in detail the figfig. 3. This is applied to an electrically insulating base 310, to electrically insulate it from the metallic substrate, namely the component to be monitored. This electrically insulating base 310 made of e.g. ceramic, plastic, mica or similar insulating materials.

The magnetic conductor 111 of the magnetic measurement circuit 110 at its two ends to the two couples second magnetic inputs 311a, 311b of the measuring chip 300. The two inputs have this 311a, 311b on a magnetic coupling by means of ferrite 312 while electrical insulation. Between the two inputs 311a, 311b two magnetic measuring sections 313a, 313b are provided, which are used for monitoring the interruption 130 with the spacing a of the magnetic conductor 111.

Also for the compensation circuit 210 magnetic inputs 311c, 311d on measuring chip 300 are provided, which are in turn over two measuring sections 313c, 313d connected to one another.

Connections are provided for the supply of the measuring chip finally 320 300 with electric current and signal outputs for evaluating the measuring signals obtained 330.

The operation of the force sensor 100 according to the invention can be described as follows:

During the monitoring of a component, on which the force sensor 100 is applied, both the magnetic measuring circuit 110 and the compensation circuit 210 have a constant magnetic field. However on a deformation of the component in the region of the interruption of the magnetic measurement circuit 110 130, so that the clearance varies a of the interruption and thus the induced magnetic field 130, wherein the resulting change in the magnetic flux in the measurement circuits 110, 210 the measuring sections 313a, 313b, 313c, 313d detected is over. Evaluation electronics (not shown) can be analyzed in a corresponding change of the magnetic flux and output a warning regarding the stability of the component optionally for example.

In another embodiment of the invention 100 is represented figfig. 4 force sensor. The force sensor 100 is constructed in two parts here, a first part being arranged, the monitoring part on a component to be monitored 100a 1. A second portion, the measuring part 100b of the force sensor 100 is on a second component spaced from the first component via a gap 1 3 2.

The outer magnetic measuring circuit having a first portion 110 is 110a, whose magnetic conductor 111 has the interruption 130, on the component to be monitored 1, is arranged with a second part be lifted during excitation magnet 120 on the component 2. Also the internal magnetic compensation circuit 210 is in two parts, namely a first part 210a on the first component 1 and arranged with its second part 210b with its conductive trace on the second component 2 is 211, constructed. The conductor tracks 111, 211 ends respectively in said measuring chip 300.

This two-piece structure of the invention with two interruptions force sensor 100, namely the interruption of the magnetic conductor track 130 111 and the gap 3, allows two components 1, 2 of the first component to monitor any deformation over a 1. This changes, as previously described, at a deformation of the first component 1 and thus the magnetic flux in the interrupt the spacing a 130 within the force sensor 100. The relative position of the two components is also monitored but 1, 2 to each other. Since the two excitation magnet 120, on the second component 2 in close proximity to the conductor tracks 111,220 are, 112 arranged on the first component 1, the magnetic flux changes again, when the gap between the two members 3 1, 2 increased or decreased, or the position of the first component 1 moves relative to the second component 2, its distance from one another without changes.

The component to be monitored 1 is made of a magnetic material, it is necessary, the magnetic measuring circuit 110 as well as any compensation circuit 210 in isolation in this applying component 1. In a further embodiment of the invention - as in this is represented figfig. - 5 provided, that a nonmagnetic insulating layer 10 from for example copper, tin, zinc or an alloy of these elements, but also a nonmagnetic alloy of ferrous metals with phosphorus is applied by means of electroplating methods. This nonmagnetic layer 120 is deposited galvanically 10,110 with associated excitation magnet also then the magnetic measuring circuit.