Landing gear cabin door with maintenance cabin door and maintenance method

Abstract

The invention provides an undercarriage cabin door with a maintenance cabin door and a maintenance method, and the undercarriage cabin door with the maintenance cabin door comprises an undercarriage cabin door which is connected with a fuselage through a front hinge arm and a rear hinge arm and can overturn relative to the fuselage; and the maintenance cabin door is arranged on the undercarriage cabin door, and the maintenance cabin door can be opened and closed relative to the undercarriage cabin door in a shutdown state. The invention effectively solves the problem that the tire of the undercarriage is difficult to replace, and also meets the design requirements of the main undercarriage cabin door. And the working efficiency of aircraft landing gear tire replacement is effectively improved.

Description

Technical Field

[0001] This invention relates to a landing gear door with a maintenance hatch and a maintenance method thereof. Background Technology

[0002] During flight, takeoff, and landing, the landing gear bay doors open, and the landing gear extends outside the bay to bear the parking or landing loads. In flight, the landing gear bay doors close, and the landing gear retracts into the streamlined surface of the fuselage, without affecting aerodynamics. Meanwhile, during the aircraft's service life, its landing gear tires inevitably age and suffer damage. Therefore, to ensure safe takeoff and landing, when the aircraft is parked and without using jacks to raise it, maintenance work such as tire replacement can be performed by opening the maintenance doors on the landing gear bays.

[0003] The landing gear bay doors serve for airflow correction and protection, and do not participate in the overall force transmission of the fuselage structure. The design specification for landing gear bay doors is stiffness. When the aircraft is stationary, the clearance and step difference between the landing gear bay door and the fuselage skin must meet design requirements after the landing gear bay door is closed. The opening and closing of the landing gear bay door must not cause harmful deformation that affects landing gear retraction and extension. It must meet the requirement of Article 67.1 of the National Military Standard that "the cumulative effect of elastic deformation, permanent deformation, and thermal deformation caused by various usage and fatigue loads, individually or in combination, must not impede or reduce the mechanical operation of the aircraft." The maintenance hatch on the landing gear bay door provides sufficient working space for changing landing gear tires. Its design specification is stiffness, and it must also ensure that the clearance and step difference between the main door and the maintenance hatch meet design requirements, and that no harmful deformation occurs during aircraft cruise.

[0004] Existing aircraft landing gear bays have encountered difficulties in tire replacement when the aircraft is parked. A certain type of landing gear bay has improved the efficiency of changing landing gear tires when the aircraft is parked by adding a maintenance bay door, while meeting design requirements for strength and rigidity. This also solves the difficulties in tooling design for tire replacement and the problem of limited on-site construction space preventing the tires from standing upright. Summary of the Invention

[0005] In view of this, the present invention provides a landing gear door with a maintenance hatch and a maintenance method to overcome the problem of low efficiency in aircraft landing gear tire replacement.

[0006] The present invention provides the following technical solution: a landing gear door with a maintenance door, comprising: a landing gear door, which is connected to the fuselage via a front hinge arm and a rear hinge arm, and the landing gear door can be rotated relative to the fuselage; and a maintenance door, which is opened on the landing gear door and can be opened and closed relative to the landing gear door in the stopped state.

[0007] A maintenance method includes the following steps: when the aircraft is in cruise mode, keeping the first maintenance door, the second maintenance door, and the third maintenance door locked at all times; when the aircraft is in maintenance mode and requires maintenance of the front landing gear, opening the second maintenance door while keeping the first and third maintenance doors closed; when the aircraft is in maintenance mode and requires maintenance of the rear landing gear, opening the third maintenance door while keeping the first and third maintenance doors closed; and when the aircraft is in maintenance mode and requires landing gear tire replacement, opening all three maintenance doors.

[0008] Compared with the prior art, the beneficial effects achieved by at least one of the above-mentioned technical solutions of the present invention include: effectively solving the problem of difficult landing gear tire replacement, while also meeting the design requirements of the main landing gear door; and effectively improving the work efficiency of aircraft landing gear tire replacement. Attached Figure Description

[0009] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 This is a schematic diagram of the overall configuration of the landing gear bay doors; Figure 2 A schematic diagram showing the configuration of the first maintenance hatch, the second maintenance hatch, and the third maintenance hatch; Figure 3 This is a schematic diagram of the front hinge arm and the rear hinge support arm. Figure 4 This is a schematic diagram of the inside of the first maintenance hatch; Figure 5 Schematic diagram of fuselage connector assembly; The components are: 1. Landing gear door; 2. First maintenance door; 21. Piano key hinge; 22. Docking strip; 3. Second maintenance door; 4. Third maintenance door; 5. Front hinge arm; 6. Rear hinge arm; 7. Gooseneck joint; 8. Fuselage joint. Detailed Implementation

[0011] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0012] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0013] The following detailed description, with reference to Figures 1-5, illustrates a specific embodiment of a main landing gear door with a maintenance hatch according to the present invention. This embodiment is based on the defined technical solution, ensuring full disclosure and feasibility of the technical features.

[0014] The main landing gear door with maintenance access of the present invention is mainly composed of landing gear door 1, first maintenance door 2, second maintenance door 3, third maintenance door 4, front hinge arm 5, rear hinge arm 6, gooseneck joint 7, fuselage connection support 8, docking strip 22, sealing components and tie rods, etc. It is assembled in the landing gear nacelle area of ​​the aircraft and forms a reliable connection with the fuselage reinforcing frame.

[0015] The landing gear door 1 is an integral streamlined structure with a smooth transition between its outline and the fuselage skin, ensuring aerodynamic performance in flight. The first maintenance door 2 is located in the upper area of ​​the landing gear door 1, while the second maintenance door 3 and the third maintenance door 4 are symmetrically arranged in the lower area of ​​the landing gear door 1 and are adjacent to each other. Together, they cover the key operating areas required for landing gear maintenance, realizing the function of zoned maintenance.

[0016] The landing gear door 1 is connected to the fuselage via the front hinge arm 5 and the rear hinge arm 6, enabling it to flip and open relative to the fuselage, thus meeting the movement requirements during landing gear retraction and extension.

[0017] Both the front hinge arm 5 and the rear hinge arm 6 are integrally machined from 7050 aluminum alloy and are designed with a U-shaped structure to avoid short bulkheads and ensure that there is no interference during the opening and closing of the hatch.

[0018] The hinge arm web is machined with full-size ribs, dividing the web into several triangular regions. The web surfaces of the triangular regions are cut off, and multiple relief holes are opened in the middle to reduce aerodynamic drag while ensuring structural strength.

[0019] One side of the hinge arm is fixedly connected to the wall panel area of ​​the landing gear door 1 through a combination of high-strength bolts and high-strength nuts; the other side is connected to the nacelle fairing bulkhead support, and the central connecting hole is hinged to the door movement mechanism through a smooth bolt, forming a stable force transmission path. The load is transmitted to the fuselage in sequence through the door wall panel, hinge arm, and nacelle fairing bulkhead.

[0020] The upper end of the first maintenance door 2 is hinged to the landing gear door 1 via a piano key hinge, so that the lower end can be flipped open and closed relative to the landing gear door 1.

[0021] The landing gear door 1 is fixedly equipped with symmetrically arranged docking plates 22 on both sides corresponding to the first maintenance door 2. The two opposite ends of the first maintenance door 2 are detachably connected to the docking plates 22 by support plate nuts to ensure connection rigidity and assembly accuracy.

[0022] The wall panel of the first maintenance door 2 adopts the same composite material structure as the landing gear door 1, namely carbon fiber honeycomb sandwich material, with aramid fabric prepreg and copper mesh film laid on the outside in sequence, taking into account both the impact resistance of sand and gravel and the requirements of lightweight.

[0023] The second maintenance door 3 and the third maintenance door 4 are both located at the lower end of the landing gear door 1. The lower end is hinged to the fuselage through a connecting assembly formed by the gooseneck joint 7 and the fuselage connecting support 8. The upper end can be flipped relative to the landing gear door 1. The two are symmetrically arranged and adjacent to each other. The lower end of the first maintenance door 2 is connected to the upper ends of the two doors.

[0024] The gooseneck joint 7 is made of aluminum alloy and is fixedly connected to the wall panels of the second maintenance door 3 and the third maintenance door 4. The fuselage connecting support 8 is welded and fixed to the fuselage reinforcing frame. The support of the gooseneck joint 7 and the lug of the fuselage connecting support 8 are connected by bolts. A sliding bushing is installed between the bolt and the support to ensure smooth door rotation.

[0025] The wall panels of the second maintenance door 3 and the third maintenance door 4 are also made of composite material structure of carbon fiber honeycomb sandwich + aramid fabric prepreg + copper mesh film. Both are equipped with multiple tie rod connection points, each with a detachable tie rod. The other end of the tie rod is connected to the fuselage reinforcement structure for limiting and fixing after the door is opened.

[0026] To ensure aerodynamic tightness during aircraft cruise, two sets of sealing components are installed: The first sealing assembly is located at the upper end of the second maintenance door 3, the upper end of the third maintenance door 4, and the connection point with the landing gear door 1. It uses an elastic sealing strip in conjunction with a pressing structure to achieve gap sealing.

[0027] The second sealing assembly is located at the lower end of the first maintenance door 2 and the upper end of the second maintenance door 3 and the third maintenance door 4. It uses elastic sealing strips of the same specification to ensure consistent overall sealing performance and avoid air leakage and noise generation.

[0028] The landing gear door 1, through the cooperation of the front hinge arm 5, the rear hinge arm 6 and the door motion mechanism, achieves a flipping motion relative to the fuselage: during the takeoff and landing phases, the door motion mechanism drives the hinge arm to rotate, causing the landing gear door 1 to open and the landing gear to extend; during the cruise phase, the door closes and locks, maintaining the design-required gap and step difference with the fuselage skin, without harmful deformation.

[0029] During cruise, the first, second, and third maintenance hatches remain fully locked through the coordinated action of the docking plate 22, the support plate nut, the gooseneck joint 7, and the tie rod, forming an integral structure with the landing gear hatch 1 to meet aerodynamic and rigidity requirements.

[0030] In maintenance mode, one or more maintenance doors can be opened by removing the corresponding connecting bolts and releasing the tie rod fixation: the first maintenance door 2 can be opened by flipping it open with a piano key hinge and can be kept open by the support rod of the ground equipment; the second and third maintenance doors can be opened by rotating the gooseneck joint 7, and the opening angle is limited by the length of the tie rod to ensure maintenance operation space.

[0031] Based on the above structural design, the maintenance method of the present invention is implemented as follows: Cruise Operation: When the aircraft is in the cruise phase, the first maintenance door 2 is locked to the support plate nut via the docking strip 22, and the second and third maintenance doors are locked to the fuselage connection support 8 via the gooseneck joint 7 and the pull rod. All three are kept in a completely closed state to ensure aerodynamic sealing and structural integrity.

[0032] Landing gear front maintenance operation: When the aircraft is parked and in maintenance mode, and the front of the landing gear needs to be inspected, only the connecting bolts and pull rods corresponding to the second maintenance door 3 are removed. The second maintenance door 3 is flipped open around the gooseneck joint 7 and fixed by the pull rod limit. The first maintenance door 2 and the third maintenance door 4 are kept closed and locked to avoid exposure of unrelated areas.

[0033] Rear landing gear maintenance operation: When the rear landing gear needs to be inspected, only remove the connecting bolts and pull rod of the third maintenance door 4, open the third maintenance door 4 and limit it with the pull rod, while the first maintenance door 2 and the second maintenance door 3 remain closed and locked.

[0034] Landing gear tire replacement operation: When the landing gear tires need to be replaced, the support plate nuts of the first maintenance door 2, the connecting bolts and tie rods of the second and third maintenance doors are removed in sequence. All three maintenance doors are opened. The first maintenance door 2 is supported by a strut, and the opening angle of the second and third maintenance doors is limited by tie rods. Together, they form a sufficient annular operating space, which can achieve upright tire replacement without the need to use jacks to lift the aircraft, solving the problem of limited construction space in traditional structures.

[0035] In this embodiment, the connection method, material selection, and structural dimensions of all components have been checked for strength and stiffness. Under various usage and fatigue loads, there is no accumulation of elastic deformation, permanent deformation, or thermal deformation that would hinder the mechanical operation of the aircraft.

[0036] The above description is merely a specific embodiment of the present invention and should not be construed as limiting the scope of the invention. Therefore, any substitution of equivalent components or equivalent changes and modifications made within the scope of protection of this patent should still fall within the scope of this patent. Furthermore, the technical features, technical features and technical solutions, and technical solutions in this invention can be freely combined and used.

Claims

1. A landing gear door with maintenance door, characterized in that, The utility model relates to a landing gear compartment door and a maintenance door, and belongs to the field of aircraft maintenance. The landing gear compartment door (1) is connected with the fuselage through a front hinged arm (5) and a rear hinged arm (6), and the landing gear compartment door (1) can be flipped relative to the fuselage. The maintenance door is opened on the landing gear compartment door (1), and the maintenance door can be opened and closed relative to the landing gear compartment door (1) in a parked state.

2. The main landing gear bay door with maintenance door according to claim 1, characterized in that, The maintenance door comprises a first maintenance door (2) located at the upper end of the landing gear compartment door (1), the upper end of the first maintenance door (2) is hinged to the landing gear compartment door (1), and the lower end of the second maintenance door (2) can be flipped relative to the landing gear compartment door (1).

3. The main landing gear bay door with maintenance access door of Claim 2, wherein, The landing gear compartment door (1) is provided with symmetrically and spacedly arranged butt strap plates (22), and the two opposite side ends of the first maintenance door (2) are connected and matched with the corresponding butt strap plates (22).

4. The main landing gear bay door with maintenance door according to claim 2, characterized in that, The maintenance door comprises a second maintenance door (3) located at the lower end of the landing gear compartment door (1), the lower end of the second maintenance door (3) is hinged to the landing gear compartment door (1), and the upper end of the second maintenance door (3) can be flipped relative to the landing gear compartment door (1).

5. The main landing gear bay door with maintenance door according to claim 4, characterized in that, The maintenance door comprises a third maintenance door (4) located at the lower end of the landing gear compartment door (1), the lower end of the third maintenance door (4) is hinged to the landing gear compartment door (1), and the upper end of the third maintenance door (4) can be flipped relative to the landing gear compartment door (1); and the second maintenance door (3) and the third maintenance door (4) are symmetrically arranged and adjacent at the lower end of the landing gear compartment door (1), and the first maintenance door (2) is connected with the second maintenance door (3) and the third maintenance door (4).

6. The landing gear bay assembly with maintenance door according to claim 5, characterized in that, The second maintenance door (3) is hinged to the fuselage through a connecting assembly formed by a swan neck joint (7) and a fuselage connecting support (8), and the third maintenance door (4), the swan neck joint (7) and the fuselage connecting support (8) form a connecting assembly hinged to the fuselage.

7. The main landing gear bay door to fuselage connection with maintenance access door of claim 6, wherein, The upper end of the second maintenance door (3) and the upper end of the third maintenance door (4) are provided with a first sealing assembly at the connecting position with the landing gear compartment door (1), and the connecting position of the second maintenance door (3) and the third maintenance door (4) with the first maintenance door (2) is provided with a second sealing assembly.

8. The main landing gear bay door with maintenance door according to claim 7, characterized in that, The second maintenance door (3) and the third maintenance door (4) are each provided with a pull rod connecting position, and the main landing gear compartment door with the maintenance door further comprises a pull rod, one end of the pull rod is connected with the pull rod connecting position, and the other end of the pull rod is connected with the fuselage.

9. The main landing gear bay door with maintenance door according to claim 8, characterized in that The second maintenance door (3) and the third maintenance door (4) are each provided with a plurality of pull rod connecting positions, and each pull rod connecting position is provided with one detachable pull rod.

10. A method of maintenance, carried out with the main landing gear bay door with maintenance door according to any one of claims 1-9, characterized in that, The utility model relates to a landing gear compartment door and a maintenance door, and belongs to the field of aircraft maintenance. When the aircraft is in a cruising state, the first maintenance door (2), the second maintenance door (3) and the third maintenance door (4) are always kept in a locked state; When the aircraft is in a maintenance state and the front part of the landing gear needs to be maintained, the second maintenance door (3) is opened, and the first maintenance door (2) and the third maintenance door (4) are kept closed; When the aircraft is in a maintenance state and the rear part of the landing gear needs to be maintained, the third maintenance door (4) is opened, and the first maintenance door (2) and the second maintenance door (3) are kept closed; When the aircraft is in a maintenance condition and landing gear tire change is required, the first maintenance door (2), the second maintenance door (3) and the third maintenance door (4) are all opened.

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