PROCESS FOR SUPPLYING POWER TO ACTUATORS ASSOCIATED WITH AIRCRAFT LANDING GEAR

ENERGY SUPPLY METHOD OF ACTUATORS ASSOCIATED WITH A LANDING GEAR OF AN AIRCRAFT

The airplanes are typically provided with a landing gear having a plurality of transporting people, whose nose undercarriage and a main landing gear units, the latter being equipped with brakes. Various actuators are associated with these undercarriages, among which:

braking actuators mounted on 1' landing gear at the wheels, to provide for braking of the aircraft. This would normally be of electromechanical brakes or hydraulic brakes;

- steering actuators, to steer the steerable wheels carried by the various landing gear units composing the landing gear, for example by 1' nose undercarriage, or, on some aircraft, by the main landing gear units;

- operation of the actuators, to cause retraction or extension of the undercarriages and associated hatches or doors. These actuators include both cylinders operating and latching hooks to retain the landing gear or doors to closed position.

For supplying power to the various actuators, typically used generating main aircraft, located at the engines of the aircraft. This may comprise hydraulic pumps or electrical generators directly operated by the engines of the aircraft. The hydraulic pumps can still be driven by electric motors powered by the electric generators of the aircraft.

Known document AC 2,479 482 equipped aircraft of various generations of hydraulic power:

a main generating comprising pumps driven by electric motors, respectively and positioned close to the two main landing gear and the nose undercarriage, and a local power supply comprising two pumps driven by the wheels of 1' auxiliary when the aircraft landing gear. The local power is used as a back-up, if the generation main were to fail.

The invention is directed to a novel method for supplying the actuators associated with the undercarriages composing the landing gear of an aircraft.

According to the invention, there is provided a method for supplying energy to the undercarriages forming the actuators associated with the landing gear of an aircraft, the aircraft comprising:

- a main power generation that operates independently of a wheel carried by the landing gear;

- local power generation comprising at least one local generator driven by the rotation of a wheel carried by one of the undercarriages;

the method comprising the following steps:

- in a nominal mode of operation, supplying said actuators by generating local energy;

- and, in one complementary operation, when the supply of power by generating local energy is insufficient, supplementing or ensure the supply of energy to said fully actuators with the main power generation.

Thus, the main power generation is only used according to the invention in that in addition to generating local energy.

This reduces the power demand addressed to the main power generation, thereby decreasing the size, leading to appreciable mass gains. Further, reference may be made simply, this being a main power generating electrical and electromechanical actuators, lowering of power generation main towards these actuators a low voltage supply line, sufficient to provide the balance of energy required. This avoids descend along the undercarriages of feeder cables to high voltage, that require shields and guards important and require the implementation of particular precautions for their maintenance because they are capable of carrying high powers.

Preferably, the generation of local energy comprises energy storage means for storing energy when the energy is not in use by the actuators or when the power demand of the actuators is less than the energy provided by the local power generation.

The invention will be better understood in light of the description which follows with reference to the drawings of the accompanying drawings of which:

figure 1 - a schematic diagram of a hydraulic architecture according to a first mode of implementation of the method of the invention, the architecture for here the feed of the orientation control 1' nose undercarriage;

figure 2 - is a schematic sectional view of the installation of a pump into a nose undercarriage wheel, forming a part of the generating local energy of Figure 1;

figure 3 - is a view similar to that of Figure 2, showing the installation of an electric generator in a wheel of a nose undercarriage, forming a part of the local power generation in an alternative implementation of the method;

- figure 4 is a schematic sectional view of a wheel of an electromechanical brake equipped with landing gear and an electric generator forming part of the local power;

figure 5 - is a schematic plan view of a rocker of main undercarriage carrying four braked wheels carrying a local generation according to the invention;

figure 6 - is a schematic plan view of an aircraft with two main landing gear units and a nose undercarriage, equipped with a locally generated according to the invention.

With reference to Figure 1, the method of the invention is here applied to feed one orientation control carried by a nose undercarriage 1 having two steerable wheels 2 along the longitudinal axis of 1' undercarriage, to direct the aircraft to the ground. As is known, the orientation control has here two jacks 3 mounted in "push pull" and adapted to rotate the rotatable part lower the nose undercarriage 1. the supply cylinders 3 is done very conventional via a hydraulic block 4 (symbolized dashed) which comprises a servo valve 5 for delivering the pressure in one or the other of the chambers of the rams 3 based on a set of orientation from a steering wheel operated by the driver, or an order generated by the onboard computer of the aircraft. Between the hydraulic block 4 and rams 3 are arranged rotating distributors which, depending on the angle of orientation of the pivotable part 1' nose undercarriage 1, switch the chambers of the rams 3 hydraulic powered by the power 4.

As is known, the hydraulic block 3 includes check valves shimmy 6, valves of a shortcircuit 7 for all chambers of the rams 3 at return when the hydraulic block 4 is not energized and thus provide free wheel orientation 2, relief valves 9 to prevent jack chambers from being deteriorated upon attempted forcible steering wheels (e.g. by a tractor towing) while the orientation control has not been neutralized, and finally booster valves 9 to fill the chambers of the rams 3 which collecition otherwise to cavitate. To this end, the pressure in the hydraulic block is maintained at a level greater than the return pressure of the aircraft by taring 10. An accumulator 11 absorbs the differences of flow rate between the chambers of the rams 3 which become filled and those which empty, and acts to maintain the pressure in the hydraulic block 4.

The nose undercarriage 1 is equipped with a local power generation 26 herein comprising two hydraulic pumps 20, each being disposed in one of the wheels 2 to be driven by the associated wheel as it rotates. Here, the pumps 20 are variable rate and thus generate energy in the form of a controlled rate of fluid under pressure as the wheels rotate. As is clearly seen in Figure 2, each of the pumps 20 is mounted on a sleeve 21 which is threaded onto the axle 22 which receives the wheel 2 the sleeve 21 being stopped in rotation about the axle by stop means not shown. The pump 20 includes a drive shaft 23 whose end cooperates with a toothed ring gear 24 mounted on the hub of the wheel 2. rotation of the wheel 2 when the aircraft moves at the airport thus causes a rotation of the drive shaft 23 of the pump 20.

It is beneficial to provide a protective means which eliminates the pressure burst likely generated by the pumps 20 during rotation of the wheels caused by the landing of the aircraft. For example, in the case of variable rate pumps as shown here, it will pull the tray of the pump to the position of zero flow, to gradually be returned to the nominal flow position following rotation of the wheels.

Returning to fig. 1, it is found that the pumps 20 of the local power supply 26 are connected in parallel and feed the hydraulic block 3 via a shuttle valve 31. The other input of the shuttle valve 31 is connected to a main power generating 100 of the aircraft, comprising pumps driven by the engines of the aircraft.

The shuttle valve 31 is part of a dispensing assembly 30 comprising:

an isolation valve - 32 which, when the hydraulic unit is powered by the local power, isolates the return line of the hydraulic block 3, so that the latter is in closed circuit with the local power;

a shut-off valve 33 - controlled mechanically upon retraction of 1' nose undercarriage for carrying the hydraulic block 3 at return when the landing gear is retracted by auxiliary bunker;

34 - a block valve electrically operated to place the hydraulic block 3 at return as the orientation control is not activated, in particular in flight with 1' landing gear deployed, or at high-speed running.

Operation of the assembly is as follows. During a normal operation mode, then the aircraft at the airport to join the airport or joining the runway, the wheels 2 rotate, causing the pumps 20 of the 26 local power generation. These flood in the block via the shuttle valve 31. To this end, the plates 20 are held pumps, by actuating cylinders 25 including springs, in a position for which the pumps 20 have a maximum flow rate. The pressure is then available from the local power generation for enabling steering of the wheels 2 and thereby direct the aircraft. As to the return port of the hydraulic block 3 orientation, it is closed through the isolation valve 32, so that the hydraulic fluid does other choices that return to the pumps 20. The fluid rotates in a closed circuit.

If one of the pumps 20 were to fail, the other pump may continue to be debited. The hydraulic block orientation 3 then receives a rate divided by two, so that the orientation of the wheels can continue to be carried out, with a decline in performance.

If the second pump 20 were to fail, or if the aircraft had a rolling speed too poor for the pumps 20 have a sufficient flow rate, then, in one complementary operation, is used the pressure and flow rate from the main power generating 100 for here replace providing pressure and flow rate by the local power.

For this purpose, commanding the valve 34 for permitting the pressure from the main power generating 100 to reach the shuttle valve 31. The same switches with the pressure from the main generating 100 supplying the hydraulic block 3 (the valve 33 is opened because 1' nose undercarriage is deployed). A bypass 40 can simultaneously control the isolation valve 32 so that it puts on the return port of the hydraulic block 3 with the return of the aircraft, and power the actuators 25 which force then the trays pumps 20 to return to their position of zero flow. The pumps 20 of the local power supply 26 are thus neutralized. The hydraulic block 3 is removed from that by generating hydraulic main 100, and the return port of the hydraulic block 101 is connected to the return of the aircraft.

In an alternative implementation illustrated in Figure 3, it is possible, rather than installing pumps in the wheels, then deliver electrical generators 35, which are connected to an electric pump (not shown) for example as part of the hydraulic block 3. thereby, the local power has now two electric generators driven by the wheels 35, and an electrical pump of which the electric motor is powered by the electric generators 35. Thus, as the wheels rotate, the electric generators 35 flood current by which the electric motor-driven pump rotates to drive the associated pump, thus providing the pressure needed to operate the hydraulic steering control. Preferably, the local power thus formed has a buffer battery inserted between the electric generators driven feed pump 35 and to store excess electrical energy generated by the electric generators, and regulate the supply of energy to the electric pump.

Thus, for the periods during which the electric generators 35 flood while the orientation is not required by the pilot, the electrical energy is then stored in the trimmed buffer battery.

Only in the case of insufficiency of charge of the battery buffer, which would enable more feeding properly the motor-driven pump, which would by the dispensing assembly 30 the supply pressure of the hydraulic block 3 to the main hydraulic generating 100.

Alternatively, it is also possible, in the case of insufficiency of buffer battery, connect the electric pump directly to the main power generation aircraft which would then provide the electricity necessary to rotate the orientation of the block electrical pump, in place of the local electrical generation.

According to another embodiment holding implements of the invention illustrated in Figure 4, the local power comprises maintaining electrical generators 150 disposed in the wheels 60 of main landing gear units.

In the illustrated example, the wheels 60 of main landing gear units are here braked by electromechanical brakes 70 disk array 71 with rotors that rotate with the rim of the wheel 60 and 61 of the stators which are rotationally fixed by a torque tube 72. The disks 71 are pressed by electromechanical actuators 73 74 carried by a facing disks. Here, the local power is used to power the actuators of the brakes.

The electric generators 150 of the local power comprise on one hand a rotor 151 which is secured to the rim 61 of the wheel and which has permanent magnets, and a wound stator 152, mounted in the periphery of a disk 153 integral with the axle. The rotation of the wheel 60 causes the induction in the wound stator 152 of an electric current which is collected by a cable 75 extending into the axle.

More specifically, and as is visible in Figure 5 which illustrates a main undercarriage 60 equipped with four-wheel brakes electromechanical 70 and carried by a rocker arm 80, the cables 75 which collect the current generated by the electric generators 150 causes the thus produced to a local unit 90 that incorporates means for rectifying the current produced thereby, means for storing current such as a battery or storage capabilities, and means for selectively dispensing the current thus stored to the bleed brakes 70, e.g. controllable power inverters. The current is then reported to the actuators 73 brakes 70 by wires 92.

Thus, on a same main undercarriage, 150 local electric generators are part of the same local electrical generation and are therefore analyzers, so that if any of the local electric generators 150 fails, the others continue to be debited and thereby providing power to the brake on the wheel of which the electric generator is failed.

Alternatively, the local generators may be assisted by merging the two wheels only and not more than four wheels, for example in local generators mutualisant the two wheels carried by the same axle, such that the pendulum will comprise two generations local.

In addition, the aircraft always gets a main power generation, including alternators driven by the engines of the aircraft, or, if necessary, by the auxiliary power unit, and, in general, batteries for providing electrical energy when the aircraft is stationary.

Thus, in a normal mode of operation, the electromechanical actuators are supplied with brake 73 90 associated with the local power supply. In practice, the electrical energy is preferably pulled storage means the local power 90, thereof for both storing surplus energy produced by the local generators 150 associated with the local power supply 150, and regulate the supply of energy to the actuators electromechanical brake 73. Has defect, if the storage means were fully emptied, the current available for braking the bleed 73, while passing through the storage means, would then be provided by the flow-through local generators 150, current flow dependent in this case of the wheel speed, and hence the velocity of movement of the aircraft. This is then merely very low speed that the local generators 150 could do more to provide a flow of current sufficient to meet a power demand of the electromechanical actuators 73. It is in this circumstance that, according to the invention, a balance of energy may be required to generating main of the aircraft. However, considering the aircraft then ultra low speed, the braking force to develop remains low, and the supplement of energy from the main generating itself remains relatively low powers involved usually on braking.

Thus, the connection 91 between the local unit and generating main for delivering that supplementing energy can be advantageously selected low voltage type. This arrangement avoids move down along the undercarriages of high-voltage cables from the main power generation, thereby saving appreciable mass which at least partially compensates the mass of the local power, which guarantees that facilitated over 1' undercarriage, and thus avoid the usual precautions with regard to high voltage cables which can be manipulated or approached by ground personnel. Thus, the only high-voltage cables present on 1 'landing gear are the cables 75 and 92, but are carried only by the balance 80, and not by the strut 1' landing gear.

This supplement energy required of the main generating then advantageously comes from low-voltage power systems of the aircraft, powered by the alternators or the battery of electric generation main.

In another embodiment, may be merging the current generated by the electric generators premises not only at an undercarriage, but at the assembly of the landing gear, or only a portion thereof, for example only the main landing gear units. The pooling enlarged increases the availability ratio actuators powered by the local power. However, this causes to raise along of the undercarriages of the concerned high-voltage cables.

May instead decide to do without any pooling, and fodder each brake 70 by the local generator carried by the associated wheel. The failure of the local generator causes a loss of the associated brake, which may be acceptable in terms of safety and the availability of 1' aircraft.

According to maintaining a third mode of implementation illustrated in Figure 6, the local power 90 comprises maintaining local electrical generators implemented the wheels 35 1' nose undercarriage 1, and serving to supply the electromechanical actuators 70 brakes on the wheels 60 of main landing gear units. The current generated by the electric generators local 35 is returned to the local unit 90 75 by the cables that extend upward along 1' nose undercarriage, to be distributed to the actuators braking by the cables 92. The local unit 90 is connected to the main generating a low voltage cable 91 to receive required from the main generating supplementing energy. Beneficially the local unit 90 for supplying the steering actuators 1' nose undercarriage.

Alternatively, recovery can also power the actuators maneuvering for extension and retraction of the landing gear units by the local power, if it is equipped with means for energy storage.

The claims should not be limited in their scope by the preferred embodiments illustrated in the examples, but are to receive the widest interpretation that conforms to the specification as a whole.