Electro-hydrostatic actuation system for a thrust reverser for an aircraft turbojet engine nacelle

Abstract

A thrust reverser device for an aircraft turbojet engine nacelle an electro-hydrostatic actuation system that includes a motor pump and a first actuation assembly. The first actuation assembly includes a series of at least two actuators configured to be attached to a movable cover of the thrust reverser and to move the movable cover or covers between a retracted position and a deployed position relative to the nacelle. The first electro-hydraulic actuation system further includes a volumetric flow divider with an inlet connected to the motor pump and at least two outlets, wherein each outlet is connected to an actuator. The volumetric flow divider is configured to receive a fluid and to supply the fluid to the actuators with an equal flow rate.

Claims

1. A thrust reverser device for an aircraft turbojet engine nacelle comprising a first movable cover configured to move between a retracted position and a deployed position with respect to the nacelle and an electro-hydrostatic actuation system, the electro-hydrostatic system comprising a motor pump, and a first actuation assembly, comprising: a series of at least two actuators configured, each of the at least two actuators being attached to the first movable cover of the thrust reverser device and to move the first movable cover between a retracted position and a deployed position relative to the nacelle; and a volumetric flow divider having an inlet connected to the motor pump and at least two outlets, a first of the at least two outlets being connected to a first of the at least two actuators and a second of the at least two outlets being connected to a second of the at least two actuators, the volumetric flow divider being configured to receive a fluid and to supply each of the at least two actuators with an equal flow rate.

2. The reverse thrust device according to claim 1, further comprising a second movable cover configured to move between a retracted position and a deployed position with respect to the nacelle, wherein the electro-hydrostatic actuation system further comprises a second actuation assembly identical to the first actuation assembly and a main volumetric flow divider connecting the motor pump to each of the first and second actuation assemblies, the main volumetric flow divider being configured to equitably supply the first and second actuation assemblies with the fluid received from the motor pump.

3. The thrust reverser device according to claim 2, wherein each actuation assembly comprises a pair of actuators and is configured to move a first and a second movable cover of the thrust reverser device, respectively, the actuators of the same pair of actuators being configured to be attached to opposite ends of the same movable cover.

4. The thrust reverser device according to claim 2, wherein the volumetric flow divider or dividers of the actuation assemblies and the main volumetric flow divider are of a gear type.

5. The thrust reverser device according to claim 2, wherein each volumetric flow divider of the actuation assemblies comprises an internal pressure limiter.

6. The thrust reverser device according to claim 1, wherein the motor pump comprises a permanent magnet synchronous electric motor associated with an axial piston bidirectional stationary displacement pump.

7. The thrust reverser device according to claim 1, wherein the electro-hydrostatic actuation system comprises a safety device arranged between the motor pump and the volumetric flow divider of the first actuation assembly, the safety device being configured to prevent an activation of the volumetric flow divider outside the landing phase of the aircraft, the safety device comprising an isolating valve and a control valve.

8. The thrust reverser device according to claim 2, wherein the electro-hydrostatic actuation system comprises a safety device arranged between the motor pump and the volumetric flow divider of the first actuation assembly, the safety device being configured to prevent an activation of the volumetric flow divider outside the landing phase of the aircraft, the safety device comprising an isolating valve and a control valve, and wherein the safety device is arranged between the motor pump and the main volumetric flow divider, the safety device being configured to prevent an activation of the main volumetric flow divider outside the landing phase of the aircraft.

9. The thrust reverser device according to claim 1, wherein the actuators are telescopic actuators.

10. The thrust reverser device according claim 1, wherein the electro-hydrostatic actuation system comprises conduits each connecting an actuator to a volumetric flow divider and a hydraulic fuse arranged on each conduit.

11. An aircraft comprising a thrust reverser device according to claim 1.

Description

DESCRIPTION OF THE DRAWINGS

(1) The disclosure will be better understood and other details, characteristics and advantages of the present disclosure will become clearer from the following description made by way of non-limiting example and with reference to the attached drawings, in which:

(2) FIG. 1, which has already been described, shows a longitudinal sectional view of a nacelle equipped with a thrust reverser device with grids according to the prior art;

(3) FIG. 2, already described, shows a three-dimensional view of the nacelle shown in FIG. 1, equipped with a thrust reverser cover in a direct jet position;

(4) FIG. 3, already described, shows the nacelle of FIG. 2 with the thrust reverser cover in a reverse jet position;

(5) FIG. 4 shows schematically a control circuit for a first embodiment of an electro-hydrostatic actuation system according to the disclosure,

(6) FIG. 5 schematically illustrates a second embodiment of an electro-hydrostatic actuation system according to the disclosure, and

(7) FIG. 6 schematically illustrates a third embodiment of an electro-hydrostatic actuation system according to the disclosure,

(8) FIGS. 4, 5 and 6 use the symbols commonly used for hydraulic circuits.

(9) The elements having the same functions in the different embodiments have the same references in the figures.

DETAILED DESCRIPTION

(10) The present disclosure relates to a thrust reverser device for an aircraft turbojet engine nacelle comprising an electro-hydrostatic actuation system. In particular, the disclosure applies to any thrust reverser device comprising at least one cover movable between a retracted position and a deployed position relative to the nacelle, the movable cover or covers being moved by such an electro-hydrostatic actuation system.

(11) The disclosure is equally applicable to the grid-type thrust reverser devices or to the door-type thrust reverser devices.

(12) FIGS. 4, 5 and 6 illustrate embodiments of an electro-hydrostatic actuation systems for thrust reverser device according to the disclosure.

(13) Whichever embodiment is illustrated, the actuation system comprises an electric motor 102 and a stationary displacement pump 104 forming a motor pump assembly 106. The pump 104 is preferably a bidirectional stationary displacement axial piston pump.

(14) The electric motor 102 is a three-phase electric motor, of the permanent magnet synchronous motor type, associated with the hydraulic pump, i.e. it is adapted to convert the electrical power of the aircraft into mechanical power (rotation and torque) for the stationary displacement pump 104. The electric motor 102 is controlled by a motor control electronics (MDE) which consists of circuitry necessary to provide the control of the EHA electric motor and comprises the circuits necessary to interface with the electrical network of the aircraft to convert a variable frequency three phase supply, for example 115V AC (nominal), to a DC bus. The DC bus supplies the inverter, which is switched to control the current in the phase windings of the electric motor.

(15) Alternatively, the electric motor can be an asynchronous motor and the pump is a variable displacement pump. In this case, instead of controlling the speed of the electric motor, a control electronic is configured to control the inclination of the cam plate of such a pump.

(16) The pump 104 is configured to operate in all four quadrants, in both directions, motor and pump.

(17) This motor pump assembly 106 is configured to supply the fluid flow rate and pressure to the system. The combination of a permanent magnet synchronous electric motor and a bi-directional stationary displacement axial piston pump ensures the best efficiency and the best performances for a motor pump assembly, as well as a high reliability.

(18) The actuation system also comprises a gas accumulator 108 arranged in parallel with the motor pump and two non-return valves 110 to compensate for the differential volume between the annular and solid chamber of the actuators, to compensate for the thermal expansion of the fluid, to compensate for the dynamic leakage and to guarantee the minimum supply pressure for the pump 104 in order to prevent the cavitation of the pump.

(19) Alternatively, the gas accumulator can be replaced by a hydraulic reservoir or tank associated with a booster pump guaranteeing a sufficient pressure upstream of the pump to ensure the correct operation.

(20) In addition, the actuation system comprises an isolating valve 112 and a control valve 114 which are known per se and through which pass two hydraulic conduits 115, 116 coming from the pump 104. Such valves comprise a sliding valve contained in a hydraulic block. The dispenser of the isolating valve 112 allows the control valve 114 to be activated, so it does not need to let much flow rate through, unlike the dispenser of the control valve 114, which lets the flow rate and the pressure through to ensure that the fluid passes through with as little pressure loss as possible. However, the dispenser of the isolating valve 112 must be as tight as possible to prevent an inadvertent activation of the dispenser of the control valve 114. The dispenser of the isolating valve 112 is smaller than the dispenser of the control valve 114.

(21) These isolating 112 and control 114 valves act as safety devices allowing to prevent the inadvertent actuation of the actuators and therefore the displacement of the movable cover of the thrust reverser device, for example outside the landing phase of the aircraft, particularly in mid-flight. In this way, they allow the actuation system to comply with the requirements required in this field of application with regard to inadvertent deployment of the movable covers.

(22) With reference to FIG. 4, two hydraulic actuators A1, A2 of the actuation system 100 are shown, preferably of the gear type, known per se, such as asymmetric cylinders, the large chamber of which is used to deploy the flaps.

(23) In order to ensure the energy consumption throughout the actuator stroke, the two actuators A1, A2 are preferably telescopic, i.e. adapted to limit the flow rate once the load is reduced.

(24) The two actuators A1, A2 are adapted and intended to move a movable cover of a thrust reverser device equipping an aircraft nacelle relative to the nacelle between a retracted position or direct jet position and a deployed position or reverse jet position. For example, they are particularly suitable for sliding a cover on a grid-type thrust reverser.

(25) In this case, the two actuators A1, A2 are preferably each attached to one end of the cover.

(26) Preferably, each actuator A1, A2 of the actuating device comprises a pressure limiter 118 arranged on each solid chamber allowing to ensure the synchronization of the actuators and to avoid a pressure amplification effect in the event of failure of one of them.

(27) In addition, the actuators are equipped with an internal locking system to comply with the safety requirements of the thrust reverser system.

(28) Referring to FIG. 4, the actuation system according to the first embodiment also comprises a volumetric flow divider 120 allowing to ensure the synchronization of the actuators A1, A2.

(29) The volumetric flow divider 120 comprises an inlet connected to the motor pump by an inlet conduit 122 and at least two outlets, each connected to an actuator A1, A2 by an outlet conduit 124. The volumetric flow divider 120 is configured to receive a fluid with an inlet flow rate and pressure, and to substantially equitably supply the fluid to the actuators with an outlet flow rate and pressure. In other words, it is configured to divide the fluid flow equally whatever the inlet pressure. For the purposes of the disclosure, substantially equitable means that the volumetric flow divider supplies the fluid to the actuators with a difference in output flow rates of less than 10%, preferably less than 5%, and even more preferably in a strictly identical manner.

(30) Preferably, the volumetric flow divider is of the gear type allowing to ensure the very precise synchronization between the actuators. In fact, the precision is such that the difference in output flow rates is less than 1%. The volumetric flow dividers ensure the same flow rate with a great precision to all the actuators. In addition, they have the advantage of not being affected by the loads on the cover of the reverser device and offer a high precision.

(31) The volumetric flow divider 120 and the two actuators form an actuation assembly E.

(32) Thus, according to the embodiment illustrated in FIG. 4, the pressure P0 and the flow rate Q0 of fluid coming from the pump 104 will be divided in two by the volumetric flow divider 120 towards the first actuator A1 with a pressure P1 and the flow rate Q1 and towards the second actuator A2 with a pressure P2 and the flow rate Q2. The difference in flow rate between Q1 and Q2 is a maximum of 1%.

(33) Preferably, the volumetric flow divider 120 is equipped with an internal pressure limiter to ensure that the two resulting pressures P1, P2 are equal.

(34) The motor pump assembly is configured to supply a demand for flow rate and pressure to the actuators of the electro-hydrostatic actuation system. This assembly allows to regulate the speed and pressure variation by means of a regulation loop contained in the motor unit. Such an electro-hydrostatic actuation system can also allow to ensure the braking of the actuators at speed using a braking resistor contained in the control electronics.

(35) At the beginning of the stroke of the cover, and therefore of the actuators, the loads are high and antagonistic. The motor pump is adapted to supply a maximum pressure for this early stage of the stroke. But when the movable cover or covers start to open, the loads help the movement and the flow rate demand is high, so it is necessary to reduce or control this demand. The electro-hydrostatic actuation system also allows the end-of-stroke loads to be controlled via a control loop so as to minimise the pressure build-up at full deployment.

(36) The actuation system according to the disclosure is configured to adapt the pressure and the flow rate demand instantaneously.

(37) Referring to FIG. 5, which illustrates a second embodiment of an electro-hydrostatic actuation system according to the disclosure, this comprises two actuation assemblies E1, E2, as defined above. This electro-hydrostatic actuation system comprises four actuators A1, A2, A3, A4 and two volumetric flow dividers 120 allowing to ensure the synchronization of the actuators A1, A2, A3, A4.

(38) Preferably, the thrust reverser device comprises two movable covers and the actuators of the same actuating assembly are preferably attached to opposite ends of the same cover. The actuators of an actuation assembly are designed to move a right-hand cover, while the actuators of the other actuation assembly are designed to move a left-hand cover.

(39) Alternatively, the thrust reverser device comprises only a movable cover. In this case, the actuators A1, A2, A3 and A4 are attached to the cover in such a way as to be evenly spaced angularly, in order to allow a balanced distribution of the actuating forces on the cover of the thrust reverser device. Advantageously, two of the actuators, for example A1 and A4, will each be attached to one end of the cover in order to obtain the best load distribution and also to avoid deformations of the cover.

(40) According to this second embodiment, the electro-hydrostatic actuation system also comprises another volumetric flow divider, hereinafter referred to as the main volumetric flow rate divider 130, connecting the motor pump to each of the first and second actuation assemblies E1, E2.

(41) The main volumetric flow divider 130 is configured to supply the fluid received from the motor pump equally to the first and second drive assemblies E1, E2.

(42) The assembly of the volumetric flow dividers 120, 130 ensure that the actuators are synchronized.

(43) According to this second embodiment, the pressure P0 and the flow rate Q0 coming from the pump 104 are divided into two lines by the main volumetric flow divider 130: one for the first actuating assembly E1 with the pressure P1 and a flow rate Q1 and the other for the second actuating assembly E2 with a pressure P2 and a flow Q2. The difference in flow rate Q2-Q1 between these two lines is within +/1%.

(44) In the same way, the pressure P1 and the flow rate Q1 are divided by the volumetric flow divider 120 of the first actuation assembly E1 into a pressure P3 and a flow rate Q3 on one line, for the actuator A1, and on the other line into a pressure P4 and a flow rate Q4, for the actuator A2. The difference between Q3 and Q4 is 1% maximum in absolute terms.

(45) In the same way, the pressure P2 and the flow rate Q2 are divided by the volumetric flow divider 120 of the second actuation assembly E2 into a pressure P5 and a flow rate Q5 on one line, for the actuator A3, and on the other line into a pressure P6 and a flow rate Q6, for the actuator A4. The difference between Q5 and Q6 is 1% maximum in absolute terms.

(46) Each volumetric flow divider 120, 130 is preferably equipped with an internal pressure limiter so as to ensure that the two resulting pressures across a flow divider are equal.

(47) FIG. 6 illustrates a third embodiment of an electro-hydrostatic actuation system according to the disclosure. This differs from that of FIG. 5 in that each actuation assembly E1, E2 each comprises a triplet of actuators A1, A2, A3 and A4, A5, A6 for moving preferably two movable covers of a thrust reverser device. The actuators of the same triplet of actuators are intended to be regularly attached between two opposite ends of the same movable cover, one triplet for a right-hand cover and one triplet for a left-hand cover.

(48) Alternatively, the thrust reverser device comprises a single movable cover. In this case, the actuators A1, A2, A3, A4, A5 and A6 are attached to the cover in such a way as to be evenly spaced angularly, in order to allow a balanced distribution of the actuating forces on the cover of the thrust reverser device.

(49) The volumetric flow divider 120 of the first actuation assembly E1 allows to ensure the synchronization of the actuators A1, A2, A3, while the volumetric flow divider 120 of the second actuation assembly E2 allows to ensure the synchronization of the actuators A4, A5, A6.

(50) In the same way as for the second embodiment in FIG. 5, the main volumetric flow divider 130 is configured to supply the fluid received from the motor pump equally to the first and second drive assemblies E1, E2.

(51) The assembly of the volumetric flow dividers 120, 130 ensure the synchronization of the assembly of the actuators.