Landing gear locking device and method

Abstract

The application provides a landing gear locking device and method. The landing gear locking device comprises a shell, a first spring, a second spring and two oil passage holes which are respectively communicated with a hydraulic system and a landing gear locking hydraulic working cavity. A piston assembly which can lock the oil passage hole by resetting the first spring is arranged between the first oil passage hole. Under the action of the hydraulic system, the piston assembly is pushed to move, so that the opening or closing of the oil passage of the landing gear locking hydraulic working cavity is realized. A valve assembly which can lock the oil passage hole by resetting the second spring is arranged in the second oil passage hole. Under the action of the hydraulic system, the valve assembly is pushed to move, so that the opening or closing of the pressure relief oil passage of the landing gear locking hydraulic working cavity is realized. The application improves the reliability of the landing gear locking, simplifies the design of the landing gear system, saves space, reduces weight and improves safety.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of landing gear oil circuit lock safety control, in particular to a landing gear locking device and method, which is applied to a hydraulic system with hydraulic locking, emergency mechanical conversion and oil circuit pulse and pressure protection functions, such as an aircraft cabin door actuating cylinder, a flap transmission mechanism and other similar functional products, and is strict in space and weight control and high in reliability requirement. BACKGROUND

[0002] The function of the landing gear locking device is to reliably fix the landing gear structure in a certain position, so that the landing gear structure can be loaded. With the continuous improvement of the reliability requirement of the landing gear system of modern aircraft, in addition to the mechanical lock, a hydraulic lock is also needed to control the opening and closing of the oil circuit of the corresponding mechanical lock. The mechanical lock and the hydraulic lock act at the same time, which can improve the reliability of the landing gear locking.

[0003] The existing patent, such as the landing gear locking device hydraulic lock disclosed in patent publication No. CN212195874U, has a technical scheme including a piston rod, a shell, a spring, a connector nozzle and the like. When the product is locked, the piston is input with hydraulic pressure from the connector nozzle to the right piston cavity, so that the piston moves to the left until the shell is limited. The hydraulic oil in the left piston cavity is returned to the oil tank from the connector nozzle, and the hydraulic lock is locked. When the product is unlocked, the left piston cavity is input with hydraulic pressure from the connector nozzle, the hydraulic pressure acts on the piston, the piston moves to the right until the plug is limited, the hydraulic oil in the right piston cavity is returned to the oil tank from the connector nozzle, and the hydraulic lock is unlocked.

[0004] However, when the landing gear moves to the position or the electromagnetic valve is switched, the oil circuit instantaneously generates hydraulic energy or the pressure rises due to temperature and other reasons. If the pressure is not relieved or the energy is not absorbed in time, the mechanical lock will be unlocked, which will cause harm. For this problem, the existing patent does not consider how to avoid this point. SUMMARY

[0005] The purpose of the present application is to provide a landing gear locking device and method, which coordinates the oil circuit control and pressure safety protection of the landing gear locking hydraulic working cavity, integrates the design in the same device, controls the opening and closing of the oil circuit of the landing gear locking hydraulic working cavity, ensures the safety of the oil circuit in the locked state, improves the reliability of the landing gear locking, simplifies the design of the landing gear system, saves space, reduces weight and improves safety.

[0006] The technical scheme of the present application is: a landing gear locking device comprises a shell, a first spring, a second spring and two oil passage holes which are respectively communicated with a hydraulic system and a landing gear locking hydraulic working cavity, a piston assembly which can lock the oil passage hole by resetting through the first spring is arranged between the first oil passage hole, under the action of the hydraulic system, the piston assembly is pushed to move, so that the opening or closing of the oil passage of the hydraulic system and the landing gear locking hydraulic working cavity is realized; a valve assembly which can lock the oil passage hole by resetting through the second spring is arranged beside the second oil passage hole, under the action of the hydraulic system, the valve assembly is pushed to move, so that the opening or closing of the pressure relief oil passage of the hydraulic system and the landing gear locking hydraulic working cavity is realized.

[0007] Preferably, a push rod which is coaxially arranged with the valve assembly is arranged beside the second oil passage hole, an external force is applied to the push rod by a mechanical method, the push rod drives the valve assembly to move, so that the oil passage of the hydraulic system and the landing gear locking hydraulic working cavity is communicated.

[0008] Another technical scheme of the present application is: a landing gear locking device comprises a spring seat, a first spring, a shell, a piston assembly, a second spring and a valve assembly, a first nozzle is arranged on one end of the shell in a radial direction, a second nozzle is arranged on the other end of the shell in a radial direction; a first communication hole, a second communication hole, a third communication hole and a fourth communication hole which are mutually communicated are arranged in the shell; a cavity is arranged on one end of the shell; the inner end of the first nozzle is communicated with the first communication hole, and the outer end of the first nozzle is connected with a hydraulic system; the inner end of the second nozzle is communicated with the fourth communication hole, and the outer end of the second nozzle is connected with a landing gear locking hydraulic working cavity; the cavity of the shell is communicated with the fourth communication hole through the third communication hole; the second communication hole is communicated with the cavity of the shell and the fourth communication hole;

[0009] the spring seat is screwed on one end of the shell which is provided with the cavity, the first spring, the piston assembly, the second spring and the valve assembly are sequentially arranged in the spring seat and the shell; the piston assembly and the valve assembly form a hydraulic working cavity which is communicated with the first communication hole with the cavity of the shell; the piston assembly moves in the cavity, so that the first nozzle, the second nozzle, the first communication hole, the second communication hole and the fourth communication hole are communicated or disconnected; the valve assembly moves in the cavity, so that the first nozzle, the second nozzle, the first communication hole, the third communication hole and the fourth communication hole are communicated or disconnected.

[0010] Preferably, a first sealing surface is arranged on the piston assembly, a second sealing surface is arranged on the shell, the first sealing surface and the second sealing surface are attached to each other, so that the first nozzle, the second nozzle, the first communication hole, the second communication hole and the fourth communication hole are disconnected.

[0011] Preferably, the valve assembly is provided with a third sealing surface, the housing is provided with a fourth sealing surface, the third sealing surface is in contact with the fourth sealing surface, so that the first nozzle, the second nozzle, the first communication hole, the third communication hole and the fourth communication hole are disconnected.

[0012] Preferably, the landing gear locking device further comprises an adjusting washer arranged between the first spring and the piston assembly.

[0013] Preferably, the piston assembly moves in the cavity at a piston opening stroke, the piston opening stroke is the distance between the piston assembly and the spring seat; the valve assembly moves in the cavity at a valve opening stroke, the valve opening stroke is the distance between the valve assembly and the housing.

[0014] Preferably, the landing gear locking device further comprises a push rod arranged in the housing, the push rod is coaxially arranged with the valve assembly.

[0015] The present application also provides a landing gear locking method, which is performed by using the above-mentioned landing gear locking device, and comprises the following steps.

[0016] When the first nozzle connected with the hydraulic system is not supplied with pressure:

[0017] The first spring piston assembly moves away from the spring seat, so that the piston assembly is in contact with the housing to seal, and the oil path of the first nozzle, the second nozzle, the first communication hole, the second communication hole and the fourth communication hole is disconnected; at the same time, the second spring pushes the valve assembly away from the spring seat, so that the valve assembly is in contact with the housing to seal, and the oil path of the first nozzle, the second nozzle, the first communication hole, the third communication hole and the fourth communication hole is disconnected; and the landing gear locking oil path is locked.

[0018] When the first nozzle connected with the hydraulic system is supplied with pressure:

[0019] Hydraulic pressure enters the hydraulic working cavity through the first communication hole, and then pushes the piston assembly to move towards the spring seat against the first spring, so that the piston assembly is in contact with the spring seat, the hydraulic pressure is connected through the oil path between the first nozzle, the first communication hole, the second communication hole, the fourth communication hole and the second nozzle, and enters the landing gear locking hydraulic working cavity, and the opening of the landing gear mechanical lock pressure supply oil path is realized.

[0020] When the hydraulic pressure of the landing gear locking hydraulic working cavity in the locked state fluctuates or is too high:

[0021] Hydraulic pressure enters through the second nozzle, the fourth communication hole, the third communication hole and pushes the valve assembly to move against the second spring to the direction of the spring seat, so that the valve assembly is separated from the shell, the hydraulic pressure enters the hydraulic working chamber, so that the first communication hole, the first nozzle and the oil path of the hydraulic system are communicated, and the opening of the landing gear locking pressure relief oil path is realized; after the pressure relief is completed, the valve assembly is reset under the action of the second spring and is attached to the shell again, and the oil path of the third communication hole is locked.

[0022] Preferably, the landing gear locking method further comprises:

[0023] When the first nozzle connected with the hydraulic system is supplied with pressure: hydraulic pressure enters the closed hydraulic working chamber through the first communication hole, and when the hydraulic pressure cannot push the piston assembly to move against the first spring, a pushing force is applied to the push rod to push the push rod to push the valve assembly to move against the second spring to the direction of the spring seat, and the hydraulic pressure enters the landing gear locking hydraulic working chamber through the oil path communication between the first nozzle, the first communication hole, the second communication hole, the fourth communication hole and the second nozzle, and the opening of the landing gear mechanical lock pressure supply oil path is realized.

[0024] Compared with the related art, the present application has the beneficial effects that: two oil passage holes respectively communicated with the hydraulic system and the landing gear locking hydraulic working chamber are arranged in the same shell, a piston assembly locked and reset by the first spring is arranged between the two oil passage holes, under the action of hydraulic pressure, the piston assembly is pushed to move, and the opening and closing of the oil path between the hydraulic system and the landing gear locking hydraulic working chamber are realized; a valve assembly locked and reset by the second spring is arranged in the other oil passage hole, when the landing gear locking hydraulic working chamber is in the locked state and the hydraulic pressure pulsation or pressure is too high, the pressure relief oil path can be quickly opened to avoid the mechanical lock to be opened, and the safety effect is achieved, and a push rod coaxially arranged with the hole of the valve assembly is arranged on the bypass of the oil passage hole, an external force is applied to the push rod by a mechanical method to drive the push rod to move, the oil path between the hydraulic system and the landing gear locking hydraulic working chamber is communicated, the redundancy design is realized, the mechanical lock is cooperated and coordinated, the reliability and safety of the landing gear locking are improved, the design of the landing gear system is simplified, the space is saved, and the weight is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 FIG. 1 is a schematic diagram of a cross-sectional view of a landing gear locking device provided by the present application in a normal open state when the first nozzle I is supplied with pressure;

[0026] Figure 2 FIG. 2 is a schematic diagram of another cross-sectional view of the landing gear locking device provided by the present application in a normal open state when the first nozzle I is supplied with pressure;

[0027] Figure 3 FIG. 3 is a schematic diagram of a cross-sectional view of the landing gear locking device provided by the present application in a normal open state when the first nozzle I is not supplied with pressure.

[0028] Figure 4 Another cross-sectional view of the landing gear locking device provided by the present application in the normal open state of the first nozzle I when supplied with pressure;

[0029] Figure 5 Another cross-sectional view of the landing gear locking device provided by the present application in the normal open state of the first nozzle I when supplied with pressure;

[0030] Figure 6 Another cross-sectional view of the landing gear locking device provided by the present application in the normal open state of the first nozzle I when supplied with pressure;

[0031] Figure 7 Another cross-sectional view of the landing gear locking device provided by the present application in the normal open state of the first nozzle I when supplied with pressure;

[0032] Figure 8 Another cross-sectional view of the landing gear locking device provided by the present application in the normal open state of the first nozzle I when supplied with pressure.

[0033] In the drawings: 1, spring seat; 2, first spring; 3, adjusting washer; 4, housing; 5, piston assembly; 6, second spring; 7, valve assembly; 8, push rod;

[0034] A1, first stop surface; A2, second stop surface; B1, first sealing surface; B2, second sealing surface; C1, third sealing surface; C2, fourth sealing surface; D, hydraulic working chamber; H1, first communication hole; H2, second communication hole; H3, third communication hole; H4, fourth communication hole; H5, fifth communication hole;

[0035] S1, piston opening stroke; S2, valve opening stroke;

[0036] I, first nozzle; II, second nozzle. DETAILED DESCRIPTION

[0037] The present application will be described in detail below with reference to the drawings and in conjunction with embodiments. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. For the sake of description, if the terms "upper", "lower", "left", "right" appear below, they only mean the upper, lower, left and right directions consistent with the drawings themselves, and do not limit the structure.

[0038] As shown in Figure 1 , Figure 2 , the landing gear locking device provided by the present embodiment includes a spring seat 1, a first spring 2, an adjusting washer 3, a housing 4, a piston assembly 5, a second spring 6, a valve assembly 7 and a push rod 8.

[0039] The housing 4 is radially provided with a first nozzle I at one end and a second nozzle II at the other end; the housing 4 is internally provided with a first communication hole H1, a second communication hole H2, a third communication hole H3 and a fourth communication hole H4 which are mutually through. One end of the housing 4 is provided with a cavity (a large cavity through the end surface of the housing 4 and a small cavity extending from the large cavity), and the other end is provided with a fifth communication hole H2; the housing 4 is further provided with a third communication hole H3 which is coaxially communicated with the fifth communication hole H2. The inner end of the first nozzle I is communicated with the first communication hole H1, and the outer end is connected with a hydraulic system. The inner end of the second nozzle II is communicated with the fourth communication hole H4, and the outer end is connected with a landing gear locking hydraulic working cavity; the second communication hole H2 is communicated with the cavity of the housing 4 and the fourth communication hole H4. The fifth communication hole H2 is internally provided with a push rod 8.

[0040] The spring seat 1 is a hollow structure, which is threadedly connected to the end of the housing 4 provided with a cavity, and the spring seat 1 extends into the large cavity. The first spring 2, the adjusting washer 3, the piston assembly 5, the second spring 6 and the valve assembly 7 are sequentially arranged in the interior of the spring seat 1 and the housing 4 from the spring seat 1. The piston assembly 5 is slidingly arranged in the interior of the spring seat 1 at the position of the large cavity of the housing 4. The piston assembly 5, the valve assembly 7 and the cavity of the housing 4 form a hydraulic working cavity D (i.e. the small cavity) which is communicated with the first communication hole H1. The piston assembly 5 moves in the cavity to connect or disconnect the first nozzle I, the second nozzle II, the first communication hole H1, the second communication hole H2 and the fourth communication hole H4. The piston assembly 5 is provided with a first sealing surface B1, the housing 4 is provided with a second sealing surface B2, and the first sealing surface B1 is abutted with the second sealing surface B2 to disconnect the first nozzle I, the second nozzle II, the first communication hole H1, the second communication hole H2 and the fourth communication hole H4.

[0041] The valve assembly 7 moves in the cavity to connect or disconnect the first nozzle I, the second nozzle II, the first communication hole H1, the third communication hole H3 and the fourth communication hole H4. The valve assembly 7 is provided with a third sealing surface C1, the housing 4 is provided with a fourth sealing surface C2, and the third sealing surface C1 is abutted with the fourth sealing surface C2 to disconnect the first nozzle I, the second nozzle II, the first communication hole H1, the third communication hole H3 and the fourth communication hole H4.

[0042] The distance of the movement of the piston assembly 5 in the cavity is a piston opening stroke S1, which is the distance between the piston assembly 5 and the spring seat 1; the distance of the movement of the valve assembly 7 in the cavity is a valve opening stroke S2, which is the distance between the valve assembly 7 and the housing 4.

[0043] One end of the first spring 2 is pressed inside the spring seat 1, and the other end is pressed on the piston assembly 5, so that the first sealing surface B1 of the piston assembly 5 is in contact and compression with the second sealing surface B2 of the shell 4 to form a seal, and under the action of hydraulic pressure, the control hydraulic pressure is connected and disconnected through the first nozzle I, the first communication hole H1, the second communication hole H2, the fourth communication hole H4 and the second nozzle II, so that the opening and closing of the landing gear locking hydraulic working cavity oil path are realized. One end of the second spring 6 is pressed on the piston assembly 5, and the other end is pressed on the valve assembly 7, so that the valve assembly 7 is guided through the third communication hole H3, and the third sealing surface C1 is in contact and compression with the fourth sealing surface C2 of the shell 4 to form a seal, and under the action of the pressure of the second nozzle II and the landing gear locking hydraulic working cavity locking state, the control hydraulic pressure is connected and disconnected through the second nozzle II, the fourth communication hole H4, the third communication hole H3, the first communication hole H1 and the first nozzle I, so that the opening and closing of the landing gear mechanical lock hydraulic working cavity oil path are realized, and the reliability and safety of the landing gear locking are improved.

[0044] The fifth communication hole H5 at the other end of the shell 4 is provided with a push rod 8, and an external force is applied to the push rod 8 by a mechanical method to drive the valve assembly 7 to overcome the second spring 6 and move to the valve opening stroke S2, and the hydraulic pressure is connected through the first nozzle I, the first communication hole H1, the third communication hole H3 and the fourth communication hole H4, and the second nozzle II, so that the redundant opening of the landing gear mechanical lock hydraulic working cavity oil path is realized.

[0045] The application also provides a landing gear locking method, which is carried out by using the landing gear locking device, and includes the following steps:

[0046] As shown in Figure 1 , Figure 2 When the first nozzle I connected with the hydraulic system is not supplied with pressure:

[0047] The piston assembly 5 of the first spring 2 moves away from the spring seat 1, so that the piston assembly 5 is sealed with the shell 4, and the oil path of the first nozzle I and the second nozzle II through the first communication hole H1, the second communication hole H2 and the fourth communication hole H4 is disconnected; at the same time, the second spring 6 pushes the valve assembly 7 to move away from the spring seat 1, so that the valve assembly 7 is sealed with the shell 4, and the oil path of the first nozzle I and the second nozzle II through the first communication hole H1, the third communication hole H3 and the fourth communication hole H4 is disconnected. Together with the landing gear mechanical lock, the landing gear locking oil path is locked.

[0048] As shown in Figure 3 , Figure 4 When the first nozzle I connected with the hydraulic system is supplied with pressure:

[0049] Hydraulic pressure enters the hydraulic working chamber D through the first connecting hole H1, and then pushes the piston assembly 5 to move towards the spring seat 1 against the first spring 2, so that the piston assembly 5 is in contact with the spring seat 1. The hydraulic pressure is connected through the first nozzle I, the first connecting hole H1, the second connecting hole H2, the fourth connecting hole H4 and the oil passage between the second nozzle II, and enters the landing gear locking hydraulic working chamber, thereby opening the landing gear mechanical lock pressure oil passage.

[0050] like Figure 5 , Figure 6 As shown, when nozzle I connected to the hydraulic system is pressurized, hydraulic pressure enters the closed hydraulic working chamber D through the first connecting hole H1. When the hydraulic pressure cannot push the piston assembly 5 to move towards the spring seat 1 against the first spring 2, an external force can be applied mechanically to push the push rod 8 to drive the valve assembly 7 to move towards the spring seat 1 against the second spring 6 until the valve 7 opens for stroke S2 ​​(the third sealing surface C1 and the fourth sealing surface C2 separate, and the seal at this part is released). The hydraulic pressure is connected through the first nozzle I, the first connecting hole H1, the third connecting hole H3 and the fourth connecting hole H4, and the oil circuit between the second nozzle II, and then the hydraulic pressure enters the landing gear locking hydraulic working chamber, and then the hydraulic pressure enters the mechanical lock hydraulic working chamber, realizing the opening of the landing gear mechanical lock pressurization oil circuit.

[0051] like Figure 7 , Figure 8 As shown, when the landing gear locking hydraulic working chamber is locked, hydraulic pulsation or excessive pressure occurs. Hydraulic fluid flows through the second nozzle II, the fourth connecting hole H4, and the third connecting hole H3, pushing the valve assembly 7 against the second spring 6 towards the spring seat 1 to the valve opening stroke S2 ​​(the third sealing surface C1 disengages from the fourth sealing surface C2, releasing the seal at this point). Hydraulic fluid then enters the hydraulic working chamber D, and subsequently connects to the hydraulic system's oil circuit via the first connecting hole H1, the first nozzle I, and the hydraulic system's oil circuit. This enables a rapid response to open the landing gear locking pressure relief oil circuit, preventing the mechanical lock from being unlocked and providing a safety function. After pressure relief, under the action of the second spring 6, the valve assembly 7 automatically and quickly resets, and the third sealing surface C1 and the fourth sealing surface C2 contact and press together, forming a seal and locking the oil circuit of the third connecting hole H3.

[0052] The present application sets two oil holes respectively communicating with the hydraulic system and the landing gear locking hydraulic working chamber in the same component, sets a piston assembly through spring reset and locking between the oil holes, and pushes the piston assembly to move under the action of the system hydraulic pressure to realize the opening and closing of the landing gear locking hydraulic working chamber oil way.

[0053] The landing gear locking device can control the opening and closing of the landing gear locking hydraulic working chamber oil way and the safety of the locking oil way, and redundantly designs the mechanical opening oil way to improve the reliability and safety of the landing gear locking. When the hydraulic system supplies pressure, the hydraulic pressure overcomes the compression force of the built-in piston assembly, pushes the piston assembly to move, and thus opens the landing gear locking hydraulic working chamber pressure supply oil way to realize the opening of the mechanical lock.

[0054] The landing gear locking device integrates the locking, pressure safety protection and emergency communication functions of the hydraulic oil way in the same device, respectively forms corresponding function working chambers, realizes the control of the landing gear locking hydraulic working chamber oil way, simplifies the landing gear system and structure, saves space, reduces weight, and improves safety.

[0055] The above description is only an embodiment of the present application, and does not limit the patent range of the present application. Any equivalent structure or equivalent flow transformation using the content of the present application specification and drawings, or direct or indirect application in other related technical fields, is also included in the patent protection range of the present application.

Claims

1. A landing gear locking device, characterised in that, The application relates to a hydraulic system and landing gear locking hydraulic working cavity communication device, which comprises a shell (4) provided with a first spring (2), a second spring (6) and two oil passage holes communicated with the hydraulic system and the landing gear locking hydraulic working cavity. A push rod (8) is arranged beside the second oil passage hole and coaxially arranged with the valve assembly (7); an external force is applied to the push rod (8) by a mechanical method to drive the valve assembly (7) to move, so that the oil passage of the hydraulic system and the landing gear locking hydraulic working cavity is communicated.

2. A landing gear locking device, characterised in that, The device comprises a spring seat (1), a first spring (2), a shell (4), a piston assembly (5), a second spring (6), a valve assembly (7) and a push rod (8). The spring seat (1) is screw-connected to one end of the shell (4) provided with a cavity; the first spring (2), the piston assembly (5), the second spring (6) and the valve assembly (7) are sequentially arranged in the spring seat (1) and the shell (4); the piston assembly (5) and the valve assembly (7) form a hydraulic working cavity (D) communicated with the first communication hole (H1) in the cavity of the shell (4); the piston assembly (5) moves in the cavity to make the first nozzle (I), the second nozzle (II), the first communication hole (H1), the second communication hole (H2) and the fourth communication hole (H4) communicated or disconnected; the valve assembly (7) moves in the cavity to make the first nozzle (I), the second nozzle (II), the first communication hole (H1), the third communication hole (H3) and the fourth communication hole (H4) communicated or disconnected.

3. A landing gear locking device according to claim 2, characterised in that, The piston assembly (5) is provided with a first sealing surface (B1), the shell (4) is provided with a second sealing surface (B2), the first sealing surface (B1) and the second sealing surface (B2) are attached, so that the first nozzle (I), the second nozzle (II), the first communication hole (H1), the second communication hole (H2) and the fourth communication hole (H4) are disconnected.

4. The landing gear locking device of claim 2, wherein The valve assembly (7) is provided with a third sealing surface (C1), the shell (4) is provided with a fourth sealing surface (C2), the third sealing surface (C1) and the fourth sealing surface (C2) are attached, so that the first nozzle (I), the second nozzle (II), the first communication hole (H1), the third communication hole (H3) and the fourth communication hole (H4) are disconnected.

5. The landing gear locking device of claim 2, wherein It also includes an adjusting washer (3) arranged between the first spring (2) and the piston assembly (5).

6. The landing gear locking device of claim 2, wherein The distance that the piston assembly (5) moves in the cavity is the piston opening stroke (S1), and the piston opening stroke (S1) is the distance between the piston assembly (5) and the spring seat (1); the distance that the valve assembly (7) moves in the cavity is the valve opening stroke (S2), and the valve opening stroke (S2) is the distance between the valve assembly (7) and the shell (4).

7. The landing gear locking device of claim 2, wherein It also includes a push rod (8) arranged in the shell (4), and the push rod (8) is coaxially arranged with the valve assembly (7).

8. A method of locking a landing gear, using a landing gear locking device according to any one of claims 2-7, characterized in that, It includes: When the first nozzle (I) connected with the hydraulic system is not supplied with pressure: The first spring (2) moves the piston assembly (5) away from the spring seat (1), so that the piston assembly (5) is attached to the shell (4) to seal, so that the first nozzle (I) and the second nozzle (II) are disconnected through the first communication hole (H1), the second communication hole (H2) and the fourth communication hole (H4); at the same time, the second spring (6) pushes the valve assembly (7) away from the spring seat (1), so that the valve assembly (7) is attached to the shell (4) to seal, so that the first nozzle (I) and the second nozzle (II) are disconnected through the first communication hole (H1), the third communication hole (H3) and the fourth communication hole (H4); the landing gear locking oil circuit is locked; When the first nozzle (I) connected with the hydraulic system is supplied with pressure: The hydraulic pressure enters the hydraulic working cavity (D) through the first communication hole (H1), and then pushes the piston assembly (5) to move towards the spring seat (1) against the first spring (2), so that the piston assembly (5) is attached to the spring seat (1), the hydraulic pressure is connected through the oil circuit between the first nozzle (I), the first communication hole (H1), the second communication hole (H2), the fourth communication hole (H4) and the second nozzle (II), and enters the landing gear locking hydraulic working cavity, so that the landing gear mechanical lock pressure supply oil circuit is opened; When the landing gear locking hydraulic working cavity is locked, the hydraulic pressure pulsates or the pressure is too high: Hydraulic pressure enters through the second nozzle (II), the fourth communication hole (H4), the third communication hole (H3) and pushes the valve assembly (7) to move against the second spring (6) to the direction of the spring seat (1), so that the valve assembly (7) is separated from the shell (4), the hydraulic pressure enters the hydraulic working chamber (D), so that the first communication hole (H1), the first nozzle (I) and the oil circuit of the hydraulic system are communicated, and the opening of the landing gear locking pressure relief oil circuit is realized. After pressure relief, the valve assembly (7) is reset and adheres to the shell (4) again under the action of the second spring (6), and the oil circuit of the third communication hole (H3) is locked.

9. The landing gear locking method according to claim 8, characterized in that, Also includes: When the first nozzle (I) connected with the hydraulic system is pressure supply: the hydraulic pressure enters the closed hydraulic working chamber (D) through the first communication hole (H1), when the hydraulic pressure cannot push the piston assembly (5) to move against the first spring (2), a pushing force is applied on the push rod (8), so that the push rod (8) pushes the valve assembly (7) to move against the second spring (6) to the direction of the spring seat (1), the hydraulic pressure is communicated through the oil circuit between the first nozzle (I), the first communication hole (H1), the second communication hole (H2), the fourth communication hole (H4) and the second nozzle (II), and enters the landing gear locking hydraulic working chamber, so that the opening of the landing gear mechanical lock pressure supply oil circuit is realized.

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