Landing gear bay door system and method of operating a landing gear bay door system

Abstract

The invention provides a landing gear bay door system comprising a landing gear bay (1) comprising an opening (8) and accommodating a landing gear in a retracted position, a landing gear bay door (2) for opening and closing the opening (8), an actuator (3) for operating the landing gear bay door (2) between an open position and a closed position, a lock (5) located within the landing gear bay (1) and latching the landing gear bay door (2) in the closed position, a stop fitting (4) located within the landing gear bay (1) and configured to connect with the landing gear bay door at least when the landing gear bay door (2) is in its latched position. The landing gear bay door system further comprises an additional actuator (6) configured to exert a force on the landing gear bay door when the landing gear bay door (2) is in its closed position and to elastically deform the landing gear bay door (2) towards the landing gear bay (1). The invention also provides a method of operating a landing gear bay door system.

Description

TECHNICAL FIELD

[0001] The present invention relates to a landing gear bay door system and a method of operating the same. The landing gear bay door system and the method of operating the same object of the present invention aims to help reduce the peak loads generated at the landing gear bay door. BACKGROUND

[0002] During flight, the landing gears are retracted in the landing gear bays which are closed by the landing gear bay doors. These doors are hydraulically operated by actuators. The doors are closed after the landing gear extension / retraction and are pulled into contact with a stopper mounted on the belly fairing.

[0003] When the landing gear bay door is in the closed position, the landing gear cannot be deployed from the landing gear bay as the landing gear bay door covers the opening to prevent the landing gear from being deployed. When the landing gear bay door is in the open position, the landing gear can be deployed from the landing gear bay.

[0004] The landing gear bay door is kept in this position by an up-lock, i.e. a lock that latches the landing gear bay door in the upright or closed position. The up-lock is mounted on the belly fairing structure of the landing gear bay.

[0005] The main landing gear bay door is pre-crushed in order to keep it in contact with the stop fitting in case of air dynamic pressure tending to open the door.

[0006] Crushing means that the landing gear bay door is forced inwards, i.e. against or towards the landing gear bay, by applying a force to the door. As a result, the landing gear bay door elastically deforms towards the landing gear bay door bay. Elastically means that the door is able to recover its shape after deformation.

[0007] The crushing or pushing is performed before locking the door, whereby the door is pre-crushed before locking the door.

[0008] The known landing gear bay door comprises a distal end, a proximal end and a hinge line between the distal end and the proximal end. An actuator is in contact with the landing gear bay door at the proximal end thereof, such that when the actuator is operated, the landing gear bay door is pivotably moved about the hinge line.

[0009] The closing operation of the known landing gear bay door system comprises the following steps:

[0010] 1. The actuator pushes the proximal end of the door in the opposite direction to the landing gear bay, such that the door rotates about the hinge line.

[0011] 2. The door comes into contact with the stop fitting.

[0012] 3. The actuator increases the load applied to the landing gear bay door to perform a pre-crushing of the door. As mentioned previously, said increase of the applied load generates a peak load which can cause problems.

[0013] 4. The uplock is latched when the door reaches the pre-crush condition.

[0014] 5. The actuator is de-pressurized. SUMMARY

[0015] It is an object of the present invention to provide a landing gear door system, comprising:

[0016] - a landing gear bay configured for accommodating a landing gear in a retracted position, said landing gear bay comprising an opening for deploying said landing gear from said landing gear bay,

[0017] - a landing gear door configured for opening and closing the opening of said landing gear bay, the landing gear bay being closed by the door when the landing gear door is in its upright position over the opening, i.e. the door is overlying the opening, the door being open in any other position than closed,

[0018] - an actuator attached to the landing gear bay and connected to the landing gear door for operating the landing gear door between the open and closed positions,

[0019] - a lock located within said landing gear bay and configured to latch the landing gear door in said closed position,

[0020] - a stop fitting located within the landing gear bay and configured to connect with the landing gear door at least when the landing gear door is in its latched position,

[0021] - an additional actuator configured to exert a force on the landing gear door when the landing gear door is in its closed position and to elastically deform the landing gear door towards the landing gear door bay.

[0022] Thereby, the claimed invention adds an additional actuator for crushing the door instead of the actuator configured for opening and closing the door to perform this task.

[0023] The additional actuator can be connected to the landing gear door bay, i.e. the additional actuator can be directly attached to the landing gear door bay or can be attached through an intermediate element located between the additional actuator and the landing gear door bay.

[0024] The additional actuator is also connected to the landing gear door when the landing gear door is in its closed position, i.e. the additional actuator can be in direct contact with the landing gear door or can be attached to an intermediate element located between the additional actuator and the landing gear door.

[0025] The claimed invention reduces the structural problems related to the peak load generated by the actuator of the landing gear door to accomplish the need of crushing the door.

[0026] The dimensions of the landing gear door, of the surrounding structure of the belly fairing and of the actuator are determined according to these peak loads. The reduction of these loads is achieved by transferring the responsibility of the door extrusion from the actuator to the additional actuator. Thus, the main actuator rotates the door and the extrusion operation is done locally by the additional actuator.

[0027] As a result, the additional actuator can be a smaller actuator. Thus, the optimization of the structure and the reduction of the actuator size are advantageously achieved by the claimed invention.

[0028] Because the latched position reached by the door is the same as the latched position of the prior art system, the operation of the door remains unchanged. When the door is in the latched position, the door contacts the stop fitting and is extruded. Thanks to the load reduction, the invention can even enable a fully electric door operation.

[0029] Another object of the invention is a landing gear door system operation method, comprising the following steps in the closing operation:

[0030] • driving the actuator so that the landing gear door moves from the open position to the closed position,

[0031] • driving the additional actuator to exert a force on the landing gear door when it is in its closed position and to elastically deform the landing gear door towards the landing gear door bay. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to complete the description and in order to provide for a better understanding of the application, a set of drawings is provided. Said drawings form an integral part of the description and illustrate preferred embodiments of the application. These drawings comprise the following figures.

[0033] Figures 1 to 5 A schematic side view of the closing sequence of a landing gear door system according to an embodiment of the invention is shown.

[0034] Figure 6 A schematic side view of a second embodiment of the invention is shown.

[0035] Figure 7 A schematic side view of an electric landing gear door system according to an embodiment of the invention is shown. Figures 1 to 5 DETAILED DESCRIPTION

[0036] Figures 1 to 7 A landing gear door system is disclosed, comprising:

[0037] - a landing gear bay (1) for housing a landing gear (not represented) in a retracted position.

[0038] ​- a landing gear bay door (2) closing the landing gear bay opening (8) and comprising a distal end (2.1), a proximal end (2.2) and a hinge line (2.3) between the distal end (2.1) and the proximal end (2.2). The proximal end (2.2) is located in the vicinity of the hinge line (2.3) of the landing gear bay door (2) and the distal end (2.1) is the opposite end of the door (2).

[0039] - an actuator (3) attached to the landing gear bay (1) and connected to the landing gear bay door (2) for operating the landing gear bay door (2) between the open and closed position. The actuator (3) can be hydraulically or pneumatically actuated. In the shown embodiment, the actuator (3) is connected to the landing gear bay door (2) in the vicinity of the proximal end (2.2).

[0040] - a lock (5) located within the landing gear bay (1) and configured to latch the landing gear bay door (2) in the closed position.

[0041] - a stop fitting (4) located within the landing gear bay (1) and configured to connect with the landing gear bay door (2) at least when the landing gear bay door (2) is in its latched position.

[0042] - an additional actuator (6) configured to exert a force on the landing gear bay door (2) when the landing gear bay door (2) is in its closed position and to elastically deform the landing gear bay door (2) towards the landing gear bay (1).

[0043] In the shown figures, the additional actuator (6) is connected with the landing gear bay (1). The additional actuator (6) can be attached to the landing gear bay (1) or to an element attached to the landing gear bay (1).

[0044] In Figures 1 to 5 the shown embodiment, a closing sequence is depicted. Figure 1 An open landing gear bay door (2) is disclosed. In Figure 2 the landing gear bay door (2) is closed and comes into contact with the lock (5). In Figure 3 the landing gear bay door (2) is latched to the lock (5). In Figure 4 the landing gear bay door (2) is pressed against the landing gear bay (1) by the exerted force and comes into contact with the stop fitting (4), and in Figure 5 the landing gear bay door (2) is fully closed and latched.

[0045] In the shown embodiment, the landing gear bay door (2) is concave with respect to the landing gear bay (1). As stated, the additional actuator (6) is configured to elastically deform the landing gear bay door (2). For the shown landing gear bay door (2), this means that the concave door is flattened towards the landing gear bay (1).

[0046] Thus, the landing gear door (2) covers the entire opening (8) of the landing gear door bay (1), preventing the entry of air into the landing gear door bay (1) that could push the door outwards or cause the door (2) to vibrate. In addition, since the landing gear door (2) is stressed by the applied force and deformation, this stress counteracts the force of such entering air. Furthermore, when the landing gear door (2) is in its elastically deformed position, the outer surface of the landing gear door bay is aerodynamically smooth.

[0047] In both embodiments, the additional actuator (6) is configured to apply a force to the landing gear door (2) once the lock (5) is latched to the landing gear door (2).

[0048] This will reduce the closing failures revealed by experience. Sometimes the actuator (3) cannot overcome the crushing force, so the lock (5) cannot be latched, creating a "door cannot be latched" condition that can force the aircraft to return to base. Since the crushing force is not applied until the lock (5) is latched, it is ensured that the landing gear door (2) will always reach the lock (5).

[0049] In Figures 1 to 5 and Figure 7 the embodiment shown, the additional actuator (6) is configured to pull the landing gear door (2) towards the landing gear door bay (1) to elastically deform the landing gear door (2) towards the landing gear door bay (1).

[0050] More specifically, the additional actuator (6) is configured to pull the lock (5) once the lock (5) latches the landing gear door (2).

[0051] In addition, the additional actuator (6) is attached to the lock (5). The additional actuator (6) is also attached to the landing gear door bay (1).

[0052] Thus, once the landing gear door (2) is latched to the lock (5), the additional actuator (6) pulls the lock (5) and applies a force to the landing gear door (2). The additional actuator (6) is adapted to pull the lock (5) and the lock (5) is configured to pull the landing gear door (2) so that it is elastically deformed towards the landing gear door bay (1), as shown in Figure 4 .

[0053] Since the displacement of the lock (5) is on the order of a few millimeters, the additional actuator (6) can be a pulling device such as a screw rod that can generate enough force to cause the landing gear door (2) to crush against the landing gear door bay (1).

[0054] Another embodiment of the invention is shown in Figure 6 .

[0055] In both embodiments, the actuator (3) is connected to the landing gear bay door (2) in the vicinity of the proximal end (2.2) and the additional actuator (6) is configured to be connected to the landing gear bay door (2) in the vicinity of the distal end (2.1). Thereby, the actuator (3) and the additional actuator (6) contact the landing gear bay door (2) away from each other along the door.

[0056] In Figure 6 the additional actuator (6) is configured to:

[0057] - contact the landing gear bay door (2) in the closed position in the vicinity of the distal end (2.1), and

[0058] - push the landing gear bay door (2) in the opposite direction of the landing gear bay (1) and elastically deform the landing gear bay door (2) towards the landing gear bay (1).

[0059] Thereby, in this embodiment, the additional actuator (6) is configured to push the landing gear bay door (2) from the distal end (2.1) of the landing gear bay door (2).

[0060] In Figure 6 the embodiment shown in the figure, to perform the squeezing operation, the landing gear bay door (2) is pushed by the additional actuator (6) from the bay door stop fitting (4) instead of being pulled from the lock (5).

[0061] In both embodiments, a force is applied to the landing gear bay door (2) which causes the landing gear bay door (2) to deform towards the landing gear bay (1). Depending on the position where the force is applied on the door (2), the deformation of the landing gear bay door (2) is achieved by pulling the landing gear bay door (2) or pushing the landing gear bay door (2).

[0062] More specifically, the hinge line (2.3) of the landing gear bay door (2) is located between the actuator (3) and the additional actuator (6) and the lock (5). The hinge line (2.3) is located in the vicinity of the actuator (3) and the lock (5) is located in the vicinity of the additional actuator (6).

[0063] As mentioned, in the shown embodiment, the additional actuator (6) is attached to the stop fitting (4).

[0064] Additionally, the position where the stop fitting (4) is configured to contact the landing gear bay door (2) is closer to the distal end (2.1) compared to the position where the lock (5) is configured to contact the landing gear bay door (2).

[0065] In the prior art, high loads are necessary because the force application point of the actuator (3) is very close to the hinge line (2.3) which is located in the hinge fitting (7), while the bay door stop fitting (4) and the lock (5) are far away from the actuator (3).

[0066] In Figure 7 In the embodiment of the application, the actuator (3) is electrically actuated. In addition, the additional actuator (6) is also electrically actuated.

[0067] The method of operation of the landing gear bay door system of the embodiment shown comprises the following steps for the closing operation of the landing gear bay door (2):

[0068] - driving the actuator (3) so that the landing gear bay door (2) moves from the open position to the closed position,

[0069] - driving the additional actuator (6) to exert a force on the landing gear bay door (2) when it is in its closed position and to elastically deform the landing gear bay door (2) towards the landing gear bay (1).

[0070] As mentioned, in both embodiments, before the additional actuator (6) pulls or pushes the landing gear bay door (2), the lock (5) is latched to the landing gear bay door (2) in the closed position.

[0071] In Figures 1 to 5 In the embodiment of the application, when the additional actuator (6) is driven, it pulls the landing gear bay door (2) towards the landing gear bay (1).

[0072] In the embodiment shown, the additional actuator (6) is attached to the lock (5) and the lock (5) pulls the landing gear bay door (2).

[0073] Finally, when the landing gear bay door (2) is latched, the actuator (3) is de-energized.

[0074] In Figure 6 In the embodiment of the application, the step of driving the additional actuator (6) comprises the step of the additional actuator (6) pushing the landing gear bay door (2) in the opposite direction to the landing gear bay (1).

[0075] More particularly, the step of the additional actuator (6) pushing the landing gear bay door (2) comprises the step of bringing the landing gear bay door (2) into contact with the additional actuator (6) in the closed position, the additional actuator being located in the stop fitting (4).

Claims

1. A landing gear bay door system comprising: - a landing gear bay (1) configured for housing a landing gear in a retracted position, the landing gear bay (1) comprising an opening (8) for the landing gear to be deployed from the landing gear bay (1), - a landing gear bay door (2) configured for opening and closing the opening (8) of the landing gear bay (1), - an actuator (3) attached to the landing gear bay (1) and connected to the landing gear bay door (2) for operating the landing gear bay door (2) between an open position and a closed position, - a lock (5) located within the landing gear bay (1) and configured to latch the landing gear bay door (2) in the closed position, - a stop fitting (4) located within the landing gear bay (1) and configured to connect with the landing gear bay door at least when the landing gear bay door (2) is in its latched position, characterized in that the landing gear bay door system further comprises an additional actuator (6) configured to exert a force on the landing gear bay door (2) when the landing gear bay door (2) is in its closed position and to elastically deform the landing gear bay door (2) towards the landing gear bay (1).

2. The landing gear bay door system according to claim 1, wherein the additional actuator (6) is configured to exert a force on the landing gear bay door (2) once the lock (5) is latched to the landing gear bay door (2).

3. The landing gear bay door system according to claim 1, wherein the additional actuator (6) is configured to pull the landing gear bay door (2) towards the landing gear bay (1).

4. The landing gear bay door system according to claim 2, wherein the additional actuator (6) is configured to pull the landing gear bay door (2) towards the landing gear bay (1).

5. The landing gear bay door system according to claim 3, wherein the additional actuator (6) is attached to the lock (5) and adapted to pull the lock (5) such that the lock (5) pulls the landing gear bay door (2).

6. The landing gear bay door system according to claim 4, wherein the additional actuator (6) is attached to the lock (5) and adapted to pull the lock (5) such that the lock (5) pulls the landing gear bay door (2).

7. The landing gear bay door system according to claim 1, wherein the landing gear bay door (2) comprises a distal end (2.1) and a proximal end (2.2), the actuator (3) is attached to the landing gear bay (1) and connected to the landing gear bay door (2) in the vicinity of the proximal end (2.2), and the additional actuator (6) is configured to: - contact the landing gear bay door (2) in the closed position in the vicinity of the distal end (2.1), and - push the landing gear bay door (2) in a direction opposite to the landing gear bay (1).

8. Landing gear bay door system according to claim 2, wherein said landing gear bay door (2) comprises a distal end (2.1) and a proximal end (2.2), said actuator (3) is attached to said landing gear bay (1) and connected to said landing gear bay door (2) in the vicinity of said proximal end (2.2), and said additional actuator (6) is configured to: - contact the landing gear bay door (2) in its closed position in the vicinity of said distal end (2.1), and - push said landing gear bay door (2) in a direction opposite to said landing gear bay (1).

9. Landing gear bay door system according to claim 7, wherein said landing gear bay door (2) comprises a hinge line (2.3), said hinge line (2.3) and said lock (5) are located between said actuator (3) and said additional actuator (6), said hinge line (2.3) is located in the vicinity of said actuator (3) and said lock (5) is located in the vicinity of said additional actuator (6).

10. Landing gear bay door system according to claim 8, wherein said landing gear bay door (2) comprises a hinge line (2.3), said hinge line (2.3) and said lock (5) are located between said actuator (3) and said additional actuator (6), said hinge line (2.3) is located in the vicinity of said actuator (3) and said lock (5) is located in the vicinity of said additional actuator (6).

11. Landing gear bay door system according to claim 7, wherein said additional actuator (6) is attached to said stop fitting (4).

12. Landing gear bay door system according to claim 8, wherein said additional actuator (6) is attached to said stop fitting (4).

13. Landing gear bay door system according to claim 9, wherein said additional actuator (6) is attached to said stop fitting (4).

14. Landing gear bay door system according to claim 10, wherein said additional actuator (6) is attached to said stop fitting (4).

15. Landing gear bay door system according to any one of claims 1 to 14, wherein said landing gear bay door (2) is concave with respect to said landing gear bay (1), and said additional actuator (6) is configured to flatten said landing gear bay door (2) towards said landing gear bay door bay (1).

16. Landing gear bay door system according to any one of claims 1 to 14, wherein said actuator (3) and / or said additional actuator (6) are electrically actuated.

17. A landing gear bay door system operating method, said landing gear bay door system being according to any preceding claim, and said landing gear bay door system operating method being characterized in that it comprises the following steps for the closing operation of said landing gear bay door (2): • driving said actuator (3) so that said landing gear bay door (2) moves from said open position to said closed position, • driving said additional actuator (6) to exert a force on said landing gear bay door (2) when it is in its closed position, and to elastically deform said landing gear bay door (2) towards said landing gear bay door bay (1).

18. The landing gear bay door system operating method according to claim 17, wherein the lock (5) latches the landing gear bay door (2) before the additional actuator (6) applies the force to the landing gear bay door (2).

19. The landing gear bay door system operating method according to claim 17 or 18, wherein in the step of driving the additional actuator (6), the additional actuator (6) pulls the landing gear bay door (2) towards the landing gear bay (1).

20. The landing gear bay door system operating method according to claim 19, wherein the additional actuator (6) pulls the lock (5) and the lock (5) pulls the landing gear bay door (2).

21. The landing gear bay door system operating method according to claim 17, wherein the landing gear bay door (2) comprises a distal end (2.1) and a proximal end (2.2), the actuator (3) is attached to the landing gear bay (1), connected to the landing gear bay door (2) in the vicinity of the proximal end (2.2) and the additional actuator (6) is in contact with the landing gear bay door (2) in the closed position in the vicinity of the distal end (2.1), the step of driving the additional actuator (6) comprises the step of the additional actuator (6) pushing the landing gear bay door (2) in the opposite direction of the landing gear bay (1).

22. The landing gear bay door system operating method according to claim 21, wherein the step of the additional actuator (6) pushing the landing gear bay door (2) comprises the step of the landing gear bay door (2) being in contact with the additional actuator (6) which is located in the stop fitting (4).

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