Pneumatic actuator for thrust reverser

Abstract

The present invention relates to an actuation device (1) for an aircraft thrust reversal system (3), the aircraft thrust reversal system including at least one thrust reversal device (2), the actuation device (1) including at least one power drive unit (10), the at least one power drive unit being located upstream of a first aerodynamic lock (12a) and designed to actuate the input shaft (11) of the first lock (12a), the first lock being designed to actuate an output shaft located downstream when unlocked, the output shaft driving a flexible synchronous shaft (13), and the actuation device (1) further including at least one first movable cylinder rod (14b), the first movable cylinder rod being mechanically connected to the flexible synchronous shaft and fixed to a movable element of the thrust reversal device (2), the first movable rod belonging to a first set of movable rods associated with the first lock (12a).

Description

Technical Field

[0001] This invention relates to a thrust reversal system for aircraft. Background Technology

[0002] Aircraft (especially airplanes) are typically propelled by turbines (particularly turbojet engines), each housed in a nacelle configured to guide the airflow generated by the turbine. These nacelles can also house various equipment items, such as thrust reversing systems.

[0003] The purpose of a thrust reverser is to simplify aircraft landing. During operation, the thrust reverser system redirects a portion of the airflow forward, generating reverse thrust in the direction of the aircraft's displacement, thus helping to reduce the aircraft's speed. Therefore, this system complements wheel braking.

[0004] There are different types of thrust reversing systems. These can specifically include gantry reversers and grid reversers.

[0005] The thrust reversing system is based on a mechanism for actuating movable elements (such as covers or doors) that can move between two positions to engage or disengage the thrust reversing function.

[0006] Typically, thrust reversing systems (gantry or grid type) are based on displacement of the shroud via actuators (especially translational displacement of grid-type reversers). The translation is usually along a direction roughly parallel to the longitudinal axis of the nacelle.

[0007] It can be divided into a one-piece (or O-type pipe) cover and a D-type pipe cover formed by two cover halves. According to the terminology, the letters O and D respectively indicate the shape of the one-piece cover or the cover half (annular or approximately annular). The document FR 2 914700 describes the one-piece cover for the thrust reversing system in more detail.

[0008] Translation of the shroud is typically accomplished by multiple actuators. Typically, each shroud (i.e., in the case of a D-type pipe architecture, 2 or 3 half-shrouds) can have 4 or 6 actuators.

[0009] These actuators are typically actuation cylinders, with the movable rod of the actuation cylinder fixed to the cover or cover half.

[0010] Of course, it is crucial to avoid any accidental slippage of the cylinder, as opening the cover at an inappropriate time (especially during flight) could have extremely serious consequences for the aircraft and be fatal to the crew.

[0011] Therefore, especially for locking systems that act directly on the cylinders, safety devices are necessary to prevent unintended opening of the housing. Flight reverser certification requires three locks (including two so-called master locks) for each housing or housing half. The third lock is independent of the first two to prevent the reverser from being unintendedly opened during flight in the same sequence.

[0012] Patent application FR3008741 describes the direct integration of the lock into the drive cylinder via an air-driven cylinder.

[0013] The "hollow" mechanism includes a first part for an entry movement to unlock the lock, and then, once the lock is unlocked, a subsequent movement to extend the movable lever.

[0014] During the thrust reversal system shutdown, the movable rod retracts into the cylinder body, and then triggers the locking system again when the first part of the screw's stroke is reached. Movement between the blocked position and the closing stop is not prohibited.

[0015] Patent application FR3008741 provides a single power drive unit (PDU) that supplies power to two drive cylinders associated with the same half-hood. Furthermore, each cylinder is associated with a pneumatic lock.

[0016] This setup is not entirely satisfactory because experience shows that the locks do not necessarily unlock synchronously, resulting in the cover opening not always smoothly, but rather "unsmoothly." Furthermore, and most importantly, this setup requires a lock for each cylinder, which has serious adverse consequences in terms of manufacturing costs, maintenance, and quality. Summary of the Invention

[0017] One of the objectives of this invention is to improve upon existing technologies.

[0018] By using a single lock shared by multiple movable cylinder rods, the mass and corresponding cost of the thrust reversing system can be reduced, while preventing the lock from being unintentionally unlocked by forces from various movable rods downstream.

[0019] For these purposes, according to a first aspect, the invention can be achieved by an actuation device for a thrust reversing system of an aircraft, the thrust reversing system including at least one thrust reversing device, the actuation device including at least one power drive unit located on a so-called upstream side of a first pneumatic lock and adapted to actuate an input shaft of the first pneumatic lock, the first lock being adapted to actuate an output shaft located on a so-called downstream side, the downstream side being opposite to the upstream side, the output shaft driving a flexible synchronous shaft, and the actuation device further including at least a first movable cylinder rod mechanically connected to the flexible synchronous shaft and fixed to a movable element of the thrust reversing device, the first movable rod belonging to a first set of movable rods associated with the first pneumatic lock.

[0020] Therefore, according to the present invention, the synchronization of different cylinders located downstream of a single lock allows the lock to be shared by multiple cylinders, which enables a reduction in the mass and associated costs of airborne equipment.

[0021] This also helps to avoid instability and ensures smooth movement of the cylinder's movable rod by synchronizing the cylinders without dead tracks.

[0022] According to a preferred embodiment, the present invention includes one or more of the following features that can be used alone, in partial or complete combination with each other: - The output shaft is directly connected to the second movable cylinder rod, which is also fixed to the movable element of the thrust reversing device and belongs to the first group of movable rods; - The power drive unit is adapted to actuate the second pneumatic lock, and the second pneumatic lock is adapted to actuate the second set of movable rods; - The thrust reversing device includes two movable elements, wherein the first set is fixed to the first movable element and the second set is fixed to the second movable element; - The first lock and the second lock each include a preload device, which is configured to prevent any movement when the applied force is less than a preload threshold.

[0023] - The brake is inserted between the first lock and the second lock; - The actuation device also includes a flexible connecting shaft capable of transmitting force between the first set of movable rods and the second set of movable rods.

[0024] The second aspect of the invention can be achieved by a thrust reversal system comprising a thrust reversal device and an actuation device as described above.

[0025] The third aspect of the invention can be achieved by a nacelle for an aircraft, the nacelle comprising at least one thrust reversing system as described above.

[0026] Other features and advantages of the invention will become apparent from the following description of preferred embodiments of the invention, given by way of example and with reference to the accompanying drawings. Attached Figure Description

[0027] The accompanying drawings illustrate the invention: Figure 1 A schematic diagram of the propulsion components of an aircraft is shown. The aircraft includes a turbine and has an onboard thrust reversal system according to an embodiment of the present invention.

[0028] Figure 2 A thrust reversing system according to a first embodiment is schematically shown.

[0029] Figure 3 The thrust reversing system according to the second embodiment is illustrated schematically.

[0030] Figure 4 A thrust reversing system according to a third embodiment is schematically shown.

[0031] Figure 5 A thrust reversal system according to the fourth embodiment is schematically illustrated. Detailed Implementation

[0032] The thrust reversal system and its embodiments according to the invention are suitable for installation on aircraft (especially airplanes) equipped with at least one turbine (especially a turbojet engine).

[0033] Figure 1 The propulsion assembly, including the thrust reversal system, is shown schematically.

[0034] The propulsion assembly includes a turbine surrounded by a nacelle 100. The nacelle is formed around a longitudinal axis that is approximately equal to the axis of flight.

[0035] Typically, during the operation of this turbine, airflow 101 enters the nacelle 100 through an air inlet located upstream of the nacelle, passes through the fan 107, and is split into a main flow 101a and a secondary flow 101b.

[0036] The main airflow 101a flows along the main air path, which is used for the flow of gas through the gas generator.

[0037] Secondary flow 101b flows along secondary air path 102, which surrounds the gas generator and is located between the gas generator and the inner shell of nacelle 100.

[0038] The thrust reversing system includes movable elements and fixed elements attached to the nacelle 100. These movable elements include movable element 103 or a cover, and a baffle 104 actuated by a link 105.

[0039] According to an embodiment, the movable element includes an opening portion, which may include, for example, a one-piece cover (in the case of an O-type pipe) or two cover halves (in the case of a D-type pipe).

[0040] These movable elements allow for changes to the configuration of the thrust reverser.

[0041] exist Figure 1 In this configuration, the thrust reverser is in a thrust configuration known as direct injection. In this configuration, the movable shroud 103 is in the closed position, and in the closed position, the movable shroud covers the grid 106.

[0042] When the baffle 104 is in the retracted position, it does not block the secondary air path 102.

[0043] Therefore, in the direct-jet configuration, the thrust reverser enables the secondary flow 101b to be directed to the rear of the propulsion assembly, thereby driving the propulsion of the aircraft.

[0044] In a thrust-reverse configuration known as reverse jetting, the movable cover 103 slides to an open position, in which the movable cover releases an opening corresponding to the opening of the grid 106.

[0045] Furthermore, this translation of the movable cover 103 causes the baffle 104 to unfold, thereby closing the secondary air path 102.

[0046] Therefore, in a reverse-jet configuration, baffle 104 deflects all or part of the secondary flow 101b toward grid 106. These typically include blade arrangements to direct the secondary flow forward of the propulsion assembly.

[0047] In this thrust-reverse configuration, the secondary flow 101b thus generates braking reverse thrust on the aircraft.

[0048] Multiple movable elements and multiple thrust reversing systems can be arranged on the same nacelle. Therefore, thrust reversing devices are typically located on each side of the same nacelle, and each of these thrust reversing devices is associated with a corresponding actuation device.

[0049] In a manner known per se, an aircraft may include multiple propulsion components, each of which may include a thrust reversing system.

[0050] Each thrust reversing system includes a thrust reversing device and an actuation device, the thrust reversing device including, for example, the movable element described previously.

[0051] Typically, a command can be sent to one or more actuating devices. Upon receiving the electronic command, these devices can actuate the thrust reversing device, or more precisely, actuate multiple thrust reversing devices.

[0052] Depending on the type of thrust reversing device, the actuation can be mechanical.

[0053] Figure 2 The main components of the thrust reversal system 3 are shown, which helps in understanding the invention and its embodiments. Clearly, the thrust reversal system may include many other components. Similarly, the components are shown in a schematic and functional manner and are simplified for ease of understanding the invention.

[0054] In the example shown, the thrust reversing system 3 includes an actuation device 1 and a thrust reversing device 2.

[0055] In this embodiment, two movable cylinder rods 14a and 14b are fixed to a movable element of the thrust reversing device 2. When the movable rods are translated, they drive the movable element (e.g., a cover or a half-cover) to open or close.

[0056] According to the motion applied to the input shaft 11 actuated by the power drive unit 10, the movable rod can enter and exit the body of the cylinder (not shown). Therefore, the actuator is configured to convert motion (e.g., rotational motion (applied to the input shaft 11)) into translational motion (generated on the movable rods 14a, 14b).

[0057] The power drive unit 10 can be controlled by a control unit via an electrical connection (not shown). This control unit can be coupled to a relevant control component, such as an engine control unit or an aircraft instrument panel. The control unit is designed to issue commands to the power drive unit 10 to start or stop the rotary engine.

[0058] The rotational motion generated by the power drive unit 10 actuates (e.g., rotatably) the input shaft 11 of the pneumatic lock 12, for example, via a flexible shaft (or cable). The lock includes an output shaft 19, which is actuated according to the motion applied to the input shaft when the lock is unlocked.

[0059] According to one embodiment, the lock 12 can be integrated with the cylinder into the same mechanical device. According to another embodiment, the lock is structurally separate from the cylinder.

[0060] During the extension phase, motion is applied to the input shaft 11 to translate the movable rod 14a to actuate the thrust reversing device 2 (assuming, in this example, the movable rod 14a translates toward the left side of the figure).

[0061] The idler lock 12 is typically adapted to prevent translational movement of the movable rod 14a under its nominal state. For this purpose, the locking component mechanically prevents translation of both the movable and actuable rod, thereby enabling such translation. This component can be disposed directly on the movable rod or on the rotating part of the shaft.

[0062] Typically, the initial movement applied to the input shaft 11 does not drive the movable lever 14a to translate until the lock is unlocked. This unlocking can correspond to the position of the input shaft or a predetermined number of rotations.

[0063] Subsequent movement of the input shaft drives translation of the movable rod 14a, which is mechanically fixed to the output shaft of the lock. Therefore, the lock can actuate the movable shaft 14a.

[0064] Conversely, when the input shaft rotates in the opposite direction, the movable rod 14a translates in the opposite direction (towards the right side of the figure) to return to the locked position.

[0065] According to the provided device, the lock is shared by multiple movable levers 14a, 14b. In particular, this sharing makes it possible to reduce the structure of the actuating device 1 and also reduce the manufacturing and maintenance costs of the actuating device.

[0066] Furthermore, according to this device, the lock's output shaft 19 drives the flexible synchronous shaft (or cable) 13. Other equivalent mechanical transmission mechanisms can also be used to achieve the function of the flexible synchronous shaft.

[0067] Component 16 can be configured to acquire the motion of output shaft 19 and transmit the motion of output shaft 19 to flexible shaft (or cable) 13. Various mechanical mechanisms known per se can achieve this motion transmission. As an example, a helical gear can be used.

[0068] The flexible synchronous shaft 13 is designed to actuate the movable rod 14b, for example, via a mechanical coupling box 15. This mechanical coupling box is specifically designed to convert the rotational motion of the flexible shaft 13 into a translational motion applied to the movable rod 14b of the actuator. The mechanical coupling box may include the body of the actuator, into which the movable rod 14b can be inserted in a folded-back position.

[0069] Therefore, the flexible synchronous shaft 13 enables the translation of the movable rod 14b to be synchronized with the translation of the movable rod that is directly engaged with the output shaft 19 of the lock. In other words, once the lock 12 is unlocked, the two movable rods 14a and 14b can be actuated in a completely synchronized manner using the same input shaft 11.

[0070] Synchronization is accomplished by a device arranged downstream of lock 12, such that once the lock is unlocked, the multiple movable levers will be able to translate as a single component.

[0071] It should be understood that this example can be generalized to include more than two movable rods. Specifically, the same synchronizing device can transmit rotational motion to multiple mechanically connected boxes to drive translation of as many movable rods as possible. For example, multiple boxes can be connected to the same flexible synchronizing shaft 13, or multiple synchronizing shafts can have the same lock 12.

[0072] Therefore, according to the provided device, the synchronous shaft 13 is located downstream of the pneumatic lock 12, that is, at the output of the pneumatic lock and opposite to the input shaft 11 (upstream side).

[0073] The synchronization device downstream of the lock enables the prevention of any undesirable unlocking of the lock caused by possible movement of the actuator fixed to the flexible synchronization shaft.

[0074] Specifically, the upward force on the movable rod 14b and the synchronous shaft 13 cannot unlock the lock 12.

[0075] When the lock is unlocked, it can actuate all movable levers 14a and 14b. Movable lever 14b is mechanically connected to flexible synchronous shaft 13, and the movable lever is therefore actuated by output shaft 19 of lock 12.

[0076] Figure 3 Another embodiment is illustrated schematically, in which no movable lever is directly engaged with the output shaft 19 of the lock 12.

[0077] In this embodiment, the lock 12 is separate from the set of movable rods of the actuator. The lock is shared by the set of cylinders, and the movement is transmitted to the set of cylinders via gear 16.

[0078] exist Figure 3 The example shows four cylinders (and four movable levers 14a, 14b, 14c, 14d).

[0079] These movable rods can be designed to actuate the same movable element of the thrust reversing device 2, such as the cover or cover half according to an embodiment of the thrust reversing device.

[0080] According to other embodiments, such as Figure 3 As shown in the example, subgroups of these movable rods (e.g., torque sections 14a / 14b) can be configured to actuate the first movable element 2a, and another subgroup (e.g., torque sections 14c / 14d) can be configured to actuate the second movable element 2b. For example, in the case of a D-type pipe structure, the first rod subgroup is fixed to the first cover half 2a, while the second rod subgroup is fixed to the second cover half 2b. Without loss of generality, the described mechanism applies to a single movable element.

[0081] Figure 3 The embodiments described herein are largely similar to Figure 2 Examples are shown below. Common components will not be described further.

[0082] Similarly, the input shaft 11 drives multiple flexible synchronous shafts 13a, 13b, 13c, and 13d in a synchronous rotational manner. When the lock is unlocked, each of the multiple flexible synchronous shafts can translate to actuate one or more (two in the example shown) movable rods.

[0083] Mechanical connection boxes 15a, 15b, 15c, and 15d can be configured to transmit and convert the rotational motion of the flexible synchronous shaft into multiple synchronous translational motions respectively applied to the movable rods 14a, 14b, 14c, and 14d.

[0084] In this example, it can be seen that a single pneumatic lock is shared by four movable levers.

[0085] For example, according to an embodiment, the same pneumatic lock 12 can be used for one or more movable elements, such as for two halves of a D-type pipe structure. Meanwhile, synchronization between the movements of the movable rods is provided by a flexible synchronizing shaft (or cable), both in how the movable rods are actuated (since the movable rods are all configured to move when the lock is unlocked) and in the displacement speed of the movable rods (since the movable rods are all actuated by the same input screw and the same power drive unit).

[0086] Figure 4 Another embodiment is shown, wherein the actuation device 1 further includes preloading devices 17a, 17b.

[0087] In this embodiment, the same power drive unit 10 actuates the input shafts 11a and 11b of the two locks 12a and 12b respectively. Each lock 12a and 12b has output shafts 19a and 19b, which are used to actuate a set of movable rods (14a / 14b and 14c / 14d respectively) through synchronization devices (16a / 13a / 15b and 16c / 13b / 15d respectively).

[0088] It is possible for one of the two locks, 12a and 12b, to malfunction. These situations are relatively rare and are usually discovered during routine inspections of the aircraft's facilities. However, it may be beneficial to prevent such hidden faults in the locks.

[0089] If a lock malfunction prevents locking, the locking mechanism may be faulty, preventing the movable levers associated with that lock from being locked. In this case, during flight, the force corresponding to these levers is no longer blocked by the lock and can be transmitted upstream to the input screw, and then towards the power drive unit 10 to the flexible shaft. Through its structure, this force can also be transmitted to other flexible shafts, and thus to another lock. If the force is large enough, the input shaft will be actuated until the other lock is unlocked, and the corresponding movable lever is translated actuated.

[0090] In other words, a failure of one lock could cause the link to unlock one or more other locks engaged with the same power drive unit. This situation should certainly be avoided, as it would be catastrophic for the aircraft.

[0091] According to embodiments of the present invention, a mechanism for unlocking such a link that avoids locking can be provided.

[0092] exist Figure 4 In one embodiment, the first lock 12a and the second lock 12b are each configured to include a preloading device (17a and 17b, respectively).

[0093] These preload devices 17a and 17b are designed to resist any movement when the force applied to the preload device is less than the preload threshold.

[0094] Typically, the preloading device includes one (or more) springs, the prestress state of which is equal to the preloading threshold.

[0095] According to this embodiment of the invention, the preload threshold of the lock is designed to cover a task profile that is used to actuate movable levers associated with other locks (such as those encountered by the movable levers) and is prone to failure (e.g., it may correspond to the ultimate force during flight).

[0096] The preload must be sufficient to compensate for the sum of the external limit forces applied to the movable elements associated with the actuator.

[0097] More precisely, - The preload threshold of the first lock 12a corresponds to the force corresponding to the second set of movable rods 14c and 14d in the movable rod group, and - The preload threshold of the second lock 12b corresponds to the force corresponding to the first set of movable rods 14a, 14b.

[0098] Furthermore, these forces can correspond to the sum of the forces generated by each of the movable rods in a corresponding set of movable rods.

[0099] Therefore, for example, if lock 12b malfunctions, movable levers 14c and 14d can be freely displaced. External force Fc +F d (where F) c and F d The translation of the movable rods 14c and 14d is driven by the application of force.

[0100] To prevent this, lock 12a is preloaded, such that the preload threshold F is... 预施载 Make F 预施载 >F c +F d .

[0101] Therefore, the force generated by the free movement of levers 14c and 14d will not be able to unlock lock 12a. Therefore, a failure of lock 12b will not cause the link of one or more other locks to unlock.

[0102] Alternatively or additionally, a brake 20 may be provided between the input shafts of the pneumatic lock.

[0103] The brake prevents the link from unlocking without any preload in the pneumatic locks 12a and 12b.

[0104] Figure 5 Another embodiment of the invention is shown, in which the flexible connecting shaft 18 is mounted to transmit force between the first set of movable rods and the second set of movable rods without the need for a lock. Figure 5 Repeated Figure 4 The components will no longer be described.

[0105] The stiffness of the flexible shaft 18 is greater than the stiffness required to unlock locks 12a and 12b.

[0106] In a sense, the flexible shaft thus blocks the transmission of force, which would otherwise pass freely through the power drive unit 10.

[0107] Therefore, in the event of a lock malfunction, the free movement of the corresponding lever will be prevented, and the movement will not be transmitted to the movable lever corresponding to the other lock.

[0108] For example, the flexible connecting shaft 18 can be installed between the first set of movable rods and the second set of movable rods. Figure 5 In the example shown, the flexible connecting shaft 18 is installed between the mechanical connecting boxes 15b and 15c, which are associated with movable rods 14b and 14c, respectively. The movable rods 14b and 14c are actuated by flexible synchronous shafts 13a and 13b (in other words, these flexible synchronous shafts are not directly engaged with locks 12a and 12b).

[0109] Of course, the present invention is not limited to the examples and embodiments described and shown, but is defined by the claims. In particular, many variations will be apparent to those skilled in the art.

Claims

1. An actuation device (1) for a thrust reversing system (3) of an aircraft, the thrust reversing system comprising at least one thrust reversing device (2), the actuation device (1) comprising at least one power drive unit (10) located on a so-called upstream side of a first pneumatic lock (12a) and adapted to actuate an input shaft (11) of the first pneumatic lock (12a), the first pneumatic lock being adapted to actuate an output shaft located on a so-called downstream side opposite to the upstream side when unlocked, the output shaft driving a flexible synchronous shaft (13), and the actuation device (1) further comprising at least a first movable cylinder rod (14b) mechanically connected to the flexible synchronous shaft and fixed to a movable element of the thrust reversing device (2), the first movable cylinder rod belonging to a first set of movable cylinder rods associated with the first pneumatic lock (12a).

2. The actuation device according to claim 1, wherein, The output shaft is directly connected to the second movable cylinder rod (14a), which is also fixed to the movable element of the thrust reversing device (2) and belongs to the first group of movable cylinder rods.

3. The actuation device (1) according to claim 1 or 2, wherein, The power drive unit (10) is adapted to actuate a second pneumatic lock (12b), which is adapted to actuate a second set of movable cylinder rods (14c, 14d).

4. The actuation device according to claim 3, wherein, The thrust reversing device (2) includes two movable elements (2a, 2b), wherein the first set of movable cylinder rods (14a, 14b) is fixed to the first movable element (2a), and the second set of movable cylinder rods (14c, 14d) is fixed to the second movable element (2b).

5. The actuation device (1) according to claim 3, wherein, The first pneumatic lock (12a) and the second pneumatic lock (12b) each include a preload device (17a, 17b) configured to prevent any movement when the applied force is less than a preload threshold.

6. The actuation device (1) according to claim 3, wherein, The brake (20) is inserted between the first pneumatic lock (12a) and the second pneumatic lock (12b).

7. The actuation device (1) according to claim 3, the actuation device further comprising a flexible connecting shaft (18) capable of transmitting force between the first set of movable cylinder rods and the second set of movable cylinder rods.

8. A thrust reversing system (3) comprising a thrust reversing device (2) and an actuation device (1) according to any one of claims 1 to 7.

9. A nacelle (100) for an aircraft, comprising at least one thrust reversal system (3) according to claim 8.

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