A passive bogie positioner for a landing gear and a method of oil filling

Abstract

The application discloses a kind of frame landing gear passive frame positioner and oil filling method, a kind of frame landing gear passive frame positioner, including piston rod, the piston rod inner cavity is equipped with floating piston, the floating piston will the inner cavity of the piston rod be divided into A cavity and B1 cavity, the end of the other end of the piston rod is equipped with damping piece, the other end of the piston rod is plugged in plunger inner cavity, the inner wall of the piston rod cooperates with the outer wall of the plunger, the plunger is fixedly installed with limit piece at the end of the piston rod outside, the plunger and the piston rod are integrally installed in outer cylinder inner cavity, one end of the piston rod extends from the outer cylinder, and the other end of the outer cylinder is sealingly fixed with end cover.The application has simple structure, few parts, good shock damping effect, and can realize the frame positioning and sliding run oscillation bidirectional damping of frame landing gear.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of aircraft landing gear design, in particular to a passive frame positioner of a frame landing gear and a method for oil charging. BACKGROUND

[0002] By increasing the number of tires, the frame landing gear can effectively reduce the ground load transmitted by a single tire of an aircraft with a large take-off / landing weight, thereby reducing the pressure requirement of the runway.

[0003] At present, various civil wide-body aircraft of Airbus and Boeing adopt frame landing gears, and there are fewer models of frame landing gears in China. The frame landing gear of a civil wide-body aircraft usually requires maintaining a specific attitude when the landing gear is retracted, and being able to dampen the pitch oscillation of the frame with the ground to a certain extent when the aircraft is taxiing, which is the basic functional requirement of the frame positioner.

[0004] The research on the frame positioner in China has just started, and in the existing frame positioner or frame stabilizer schemes, the structure and function of some schemes are particularly complex, which also increases the weight of the landing gear and the failure risk points; some schemes fail to better achieve the functions of frame attitude positioning and taxiing oscillation damping.

[0005] Patents CN103032403A and CN108791823A respectively disclose an aircraft frame position control actuator and an aircraft landing gear frame stabilizing buffer device and a control method thereof, which realize the locking of large-angle retraction and extension and dynamic buffering during taxiing through a one-way valve, a safety valve, a control valve, a damping valve and an actuator cylinder. The product has many components and complex functions, which will inevitably increase the weight and the number of failure points of the product and reduce the reliability of the product.

[0006] Patent CN107588149A discloses a frame landing gear stabilizing buffer, which is an oil-gas cavity that maintains a neutral position when there is no external load and has a buffering effect when being pulled or pressed. The oil-gas mixing cavity in the patent performs buffering and damping, which will cause the oil level to not exceed the damping hole in some working conditions, so that effective damping cannot be generated. Moreover, the frame stabilizing buffer involved in the patent does not consider overcoming external load in the neutral position. SUMMARY

[0007] The present application solves the technical problem of the prior art, and provides a passive frame positioner of a frame landing gear, which can overcome external load and generate effective damping.

[0008] The present application also provides a method for oil charging of the passive frame positioner of the frame landing gear, which discharges the gas in the oil cavity to achieve effective damping.

[0009] To solve the above technical problems, the technical scheme adopted by the present application is: a kind of vehicle frame landing gear passive vehicle frame positioner, including piston rod, one end of the piston rod is fixedly connected with joint, floating piston is installed in the inner cavity of the piston rod, the floating piston divides the inner cavity of the piston rod into A cavity and B1 cavity, damping piece is installed at the end of the other end of the piston rod, the other end of the piston rod is plugged in the inner cavity of plunger, the inner wall of the piston rod cooperates with the outer wall of the plunger, the end of the plunger is fixedly installed with limit piece outside the piston rod, the piston rod is slidably guided in the inner cavity of the plunger, the plunger and the piston rod are integrally installed in the inner cavity of outer cylinder, the outer wall of the plunger is slidably connected with the inner wall of the outer cylinder, one end of the outer cylinder is sealingly and fixedly connected with interface, the end of the plunger is sealingly connected between the outer wall of the interface and the inner wall of the outer cylinder, one end of the piston rod extends out of the outer cylinder, the other end of the outer cylinder is sealingly and fixedly provided with end cover, and the end cover is arranged around the outer wall of the piston rod.

[0010] Inert gas is filled in the A cavity of the piston rod close to the joint, and the inner cavities B2 cavity between the B1 cavity, the inner wall of the plunger and the damping piece, and B3 cavity between the outer cylinder and the outer wall of the piston rod and the outer wall of the plunger are filled with oil.

[0011] Within the range that the floating piston can freely float, the air cavity and the oil cavity are in pressure balance. The installation position of the floating piston ensures that the floating piston can freely float within the entire aircraft operating condition envelope, and the damping effect is good.

[0012] In a preferred embodiment of the present application, a cavity C is formed between the end of the plunger close to the interface and the outer cylinder, a first communication hole for communicating the cavity C with the atmosphere is formed in the outer wall of the end of the outer cylinder close to the interface, and a plug cap for communicating with the atmosphere is arranged in the first communication hole.

[0013] In a preferred embodiment of the present application, a T-shaped exhaust hole is formed in the plug cap. The exhaust hole on the plug cap is designed to communicate with the atmosphere on both sides, thereby reducing the risk of blockage.

[0014] In a preferred embodiment of the present application, a first oil port is formed in the outer wall of the end of the outer cylinder close to the interface, a third oil port is formed in the plunger, when the end of the plunger is immediately adjacent to the end of the outer cylinder, the first oil port, the third oil port and the B2 cavity are in communication, and a sealing plug cap is arranged in the first oil port. The sealing plug cap is used for filling oil in the oil cavity.

[0015] In a preferred embodiment of the present application, the outer cylinder is provided with a second oil port on the outer wall of the end of the end cap, the second oil port is communicated with the B3 cavity, the first oil port and the second oil port are respectively located on the upper and lower sides of the outer cylinder, and the second oil port is provided with a pressure sensor. The arrangement of the sealing plug cap and the pressure sensor is beneficial to the discharge of air in the oil cavity during oil filling, and can avoid the air entrapped to cause the change of the oil pressure, thereby affecting the position of the floating piston and causing the vehicle frame to fail to reset.

[0016] In a preferred embodiment of the present application, the damping member is a damping ring, and the damping ring is provided with a damping hole in the center. The damping ring is installed on the end of the piston rod and is designed with a damping hole to damp the oil when the volume of the oil cavity changes.

[0017] In a preferred embodiment of the present application, a three-way joint is installed on the joint, and an inflation valve and a pressure sensor are respectively installed on the three-way joint. The inflation valve and the pressure sensor are respectively used for gas filling and measurement of the pressure of the gas cavity.

[0018] In a preferred embodiment of the present application, the limiting member is a screw sleeve.

[0019] The present application also discloses a method for filling oil in a passive vehicle frame positioner of a vehicle frame landing gear.

[0020] S1. The vehicle frame positioner is vertically placed with the joint upward, a hydraulic oil filling device is used to slowly fill oil through the first oil port until the oil fills the second oil port, and at this time, air may be stored in the top of the B1 cavity;

[0021] S2. The vehicle frame positioner is inverted with the joint upward, and the vehicle frame positioner is shaken to promote the discharge of the gas in the B1 cavity;

[0022] S3. The vehicle frame positioner is horizontally placed with the second oil port at the top, and the vehicle frame positioner is shaken to promote the floating of the discharged gas in the B1 cavity to the B3 cavity between the outer cylinder and the piston rod;

[0023] S4. The vehicle frame positioner is vertically placed with the joint upward, and the vehicle frame positioner is shaken to promote the floating of the gas in the B3 cavity to the vicinity of the second oil port, and then the second oil port is opened to supplement the oil and discharge the gas.

[0024] In a preferred embodiment of the present application, the liquid level line of the second oil port is higher than the oil cavity liquid level in the B3 cavity. The liquid level line of the second oil port is higher than the oil cavity liquid level in the B3 cavity, which is beneficial to the discharge of the gas.

[0025] Compared with patents CN103032403A and CN108791823A, the design requirements of the frame positioner do not include active retraction control function, the internal air pressure is used as a power source, and through internal small hole damping, the landing gear can reach the storage posture without artificial control after leaving the ground, the number of parts is less, and the principle is simpler.

[0026] Compared with patent CN107588149A, the oil and gas two cavities are separated, stable damping can be provided when the frame positioner is pulled and pressed, and the frame positioner in the neutral position can overcome the aerodynamic load in the landing gear retraction process.

[0027] Compared with the prior art, the present application has the beneficial effects that: the present application can position the frame at the storage angle after the landing gear leaves the ground without the need for a hydraulic source to drive, and can also suppress the pitch vibration of the frame during the taxiing process of the aircraft. The device has simple structure, few parts, good damping effect, and can realize two-way damping of frame positioning and taxiing oscillation of the frame landing gear. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The figure is a structural schematic diagram of the frame positioner of an embodiment of the present application.

[0029] Figure 2 The figure is a schematic diagram of the oil filling mode of the frame positioner of an embodiment of the present application.

[0030] Figure 3 The figure is a schematic diagram of the state of the frame positioner of an embodiment of the present application under different working conditions.

[0031] Figure 4 (a) is a structural schematic diagram of the blocking cap of the frame positioner of an embodiment of the present application.

[0032] Figure 4 (b) is Figure 4 A-A sectional view of (a).

[0033] In the figure: 1-joint; 2-piston rod; 3-outer cylinder; 4-plunger; 5-damping member; 6-sleeve; 7-floating piston; 8-end cover; 9-sealing blocking cap; 10-blocking cap; 11-three-way joint; 12-pressure sensor; 13-gas charging valve; 14-sealing member; 15-joint; 16-first oil port; 17-second oil port. DETAILED DESCRIPTION

[0034] As Figures 1-4As shown, a passive frame positioning device for a landing gear frame, comprising a piston rod 2, one end of the piston rod 2 is fixedly connected with a joint 1 and is sealed, the joint 1 is designed as an ear joint, and the ear joint of the frame positioning device and an outer cylinder are respectively connected with a frame assembly and a buffer strut.

[0035] A floating piston 7 is installed in the inner cavity of the piston rod 2, the floating piston 7 divides the inner cavity of the piston rod 2 into an A cavity and a B1 cavity, and a damping piece 5 is installed at the end of the other end of the piston rod 2. The other end of the piston rod 2 is inserted into the inner cavity of a plunger 4, and the inner wall of the piston rod 2 cooperates with the outer wall of the plunger 4 to guide the sliding of the plunger.

[0036] A limiting piece is fixedly installed at the end of the plunger 4 outside the piston rod 2, and the limiting piece is a screw sleeve 6 connected to the plunger. Thus, the piston rod slides in the plunger in the compression direction, and the extension direction is limited by the plunger, and the plunger needs to be pulled to move together to realize the bidirectional damping in the frame pitching oscillation process.

[0037] The piston rod 2 is slidingly guided in the inner cavity of the plunger 4, the plunger 4 and the piston rod 2 are integrally installed in the inner cavity of an outer cylinder 3, and the outer wall of the plunger 4 is slidingly connected with the inner wall of the outer cylinder 3. The plunger cooperates with the outer cylinder at both ends to make the plunger slide smoothly in the outer cylinder, and the outer end is sealed and stopped.

[0038] One end of the outer cylinder 3 is sealingly and fixedly connected with an interface 15, one end of the piston rod 2 extends out of the outer cylinder 3, the other end of the outer cylinder 3 is sealingly and fixedly provided with an end cover 8 surrounding the outer wall of the piston rod 2; and the interface 15 is connected with the buffer strut.

[0039] Inert gas is filled in the A cavity of the piston rod 2 close to the joint 1, and oil liquid is filled in the B1 cavity, the B2 cavity in the inner cavity of the plunger 4, and the B3 cavity in the inner cavity of the outer cylinder 3. That is, nitrogen is filled in the closed cavity A formed by the sealing of the ear joint and the floating piston, and hydraulic oil is filled in the closed cavities B2 and B3 formed by the sealing of the plunger and the outer cylinder. The floating piston separates the A cavity (gas cavity) and the B1 cavity (oil cavity), and the pressure of the gas cavity and the oil cavity is balanced within the range in which the floating piston can freely float. The installation position of the floating piston ensures that the floating piston can freely float within the entire aircraft operating condition envelope.

[0040] A cavity C is formed between the outer wall of the plunger 4 and the outer cylinder 3, a first communication hole is formed in the end outer wall of the outer cylinder 3 close to the interface 15, and a plug cap 10 for communicating with the atmosphere is installed in the first communication hole. A T-shaped exhaust hole is formed in the plug cap 10.

[0041] A first oil port 16 is formed in the end outer wall of the outer cylinder 3 close to the interface 15, and a sealing plug cap 9 is installed in the first oil port 16.

[0042] The outer cylinder 3 is provided with a second oil port 17 on the outer wall of the end close to the end cover 8, and the first oil port 16 and the second oil port 17 are respectively arranged on the upper and lower sides of the outer cylinder 3, and the second oil port 17 is provided with a pressure sensor 12.

[0043] The damping member 5 is a damping ring, and the central part of the damping ring is a damping hole.

[0044] The joint 1 is provided with a three-way joint 11, and the three-way joint 11 is respectively provided with an inflation valve 13 and a pressure sensor 12.

[0045] The installation method of the present application is as follows:

[0046] The screw sleeve 6 and the end cover 8 are sequentially penetrated into the outer wall of the piston rod 2;

[0047] The joint 1 is connected to the end of the piston rod 2;

[0048] The floating piston 7 is installed in the inner hole of the piston rod 2, and the floating piston assembly 7 is pushed and pulled to a position 40mm away from the installation end through a tool;

[0049] The damping member 5 is installed to the end of the piston rod 2;

[0050] The piston rod 2 is installed in the inside of the plunger 4, and the screw sleeve 6 is screwed into the threads of the plunger 4;

[0051] The plunger-piston rod assembly installed together is installed in the inner hole of the outer cylinder 3, and the end cover 8 is installed in the appropriate position;

[0052] The oil filling step for exhaust is as follows:

[0053] a) The frame positioner is vertically placed, as shown in Figure 2 a), a hydraulic oil filling device is used, and the oil is slowly filled through the first oil port (with a sealed cap), until the oil fills the second oil port (the pressure sensor), at which time the air in region I may be stored;

[0054] b) The frame positioner is inverted, as shown in Figure 2 b), the frame positioner is shaken to promote the air in region I to be discharged;

[0055] c) The frame positioner is horizontally placed, as shown in Figure 2 c), the frame positioner is shaken to promote the discharged air in region I to float to the B3 cavity;

[0056] d) The frame positioner is vertically placed, as shown in Figure 2-a) the posture shown, the vehicle frame positioner is shaken to make the gas in region II float to the vicinity of the second oil port, and then the second oil port is opened to replenish oil and discharge the gas. In Figure 2 -a) the posture shown, the liquid level of the second oil port is higher than the oil cavity liquid level, which is beneficial to the discharge of the gas.

[0057] The pressure sensor 12 and the inflation nozzle 13 are installed in the tee joint 11, and the tee joint 11 is screwed into the ear joint 1;

[0058] Nitrogen gas at the rated pressure is filled through the inflation nozzle 13;

[0059] The vehicle frame positioner is installed on the landing gear that is off the ground, at this time, the off-the-ground posture and the storage posture of the landing gear can be maintained;

[0060] When the aircraft is taxiing, the piston rod of the vehicle frame positioner is compressed and extended / compressed within a certain range, the volume of the oil cavity changes, and the oil is damped by passing through the damping ring to consume the vehicle frame oscillation energy;

[0061] When the tire is deflated in the failure condition, the piston rod will be further compressed, or the plunger will be extended until the structural limit position between the vehicle frame and the piston rod to avoid damage to the vehicle frame positioner.

[0062] After the aircraft takes off, the state of the vehicle frame positioner is as shown in Figure 3 -a) the vehicle frame positioner needs to overcome the external wind load to avoid the landing gear from being unable to be retracted into the cabin due to the vehicle frame not being in the specified position. After the gas cavity is pressurized to P value, the vehicle frame positioner can withstand the tensile and compressive loads of P·(A2-A1) and P·A1, respectively. A1 is the inner diameter of the piston rod, and A2 is the inner diameter of the outer cylinder. In the design, a reasonable pressure and cross-sectional size can be selected according to the aircraft operating envelope and the landing gear structure to meet the use requirements.

[0063] When the aircraft is taxiing or parked normally, the state of the vehicle frame positioner is as shown in Figure 3 -b) compared with the off-the-ground posture, the piston rod is compressed and can be extended within a certain range with the pitch of the vehicle frame. The compression and extension of the piston rod will cause the volume of the oil cavity / gas cavity to change, and the oil will flow through the damping hole to consume the pitch energy during the taxiing of the aircraft and inhibit the pitch vibration of the vehicle frame.

[0064] When the aircraft is taxiing or parked, the state of the vehicle frame positioner in the failure condition of the rear wheel (depending on the arrangement of the vehicle frame positioner, this description is that the vehicle frame positioner is arranged at the front of the vehicle frame) is as shown in Figure 3 -c) compared with the taxiing state, the vehicle frame positioner will be further compressed; the state of the vehicle frame positioner in the failure condition of the front wheel is as shown in Figure 3 -d) compared with the storage state, the vehicle frame positioner can be further stretched, and the plunger will be extended when stretched.

[0065] The travel of the frame positioner is also designed to account for failure conditions such as a flat tire.

Claims

1. A passive frame positioner for a frame landing gear, characterized by The piston rod (2) is fixedly connected with a joint (1) at one end, a floating piston (7) is installed in the inner cavity of the piston rod (2), the floating piston (7) divides the inner cavity of the piston rod (2) into an A cavity and a B1 cavity, a damping member (5) is installed at the end of the other end of the piston rod (2), the other end of the piston rod (2) is inserted into the inner cavity of a plunger (4), the inner wall of the piston rod (2) cooperates with the outer wall of the plunger (4), a limiting member is fixedly installed at the end of the plunger (4) outside the piston rod (2), the piston rod (2) is slidingly guided in the inner cavity of the plunger (4), the plunger (4) and the piston rod (2) are integrally installed in the inner cavity of an outer cylinder (3), the outer wall of the plunger (4) is slidingly connected with the inner wall of the outer cylinder (3), one end of the outer cylinder (3) is sealingly and fixedly connected with a connector (15), the end of the plunger (4) close to the connector (15) is sealingly connected with the inner wall of the outer cylinder (3), one end of the piston rod (2) extends out of the outer cylinder (3), the other end of the outer cylinder (3) is sealingly and fixedly provided with an end cover (8), the end cover (8) surrounds the outer wall of the piston rod (2). Inert gas is filled in the A cavity of the piston rod (2) close to the joint (1), the B1 cavity, the inner cavity B2 cavity between the inner wall of the plunger (4) and the damping member (5), and the inner cavity B3 cavity between the outer wall of the piston rod (2) and the outer wall of the plunger (4) are all filled with oil. A first oil port (16) is formed on the outer wall of the end of the outer cylinder (3) close to the connector (15), a third oil port is formed on the plunger (4), when the end of the plunger (4) is close to the end of the outer cylinder (3), the first oil port (16), the third oil port and the B2 cavity are communicated, a sealing plug cap (9) is installed in the first oil port (16). A second oil port (17) is formed on the outer wall of the end of the outer cylinder (3) close to the end cover (8), the second oil port (17) is communicated with the B3 cavity, the first oil port (16) and the second oil port (17) are respectively located on the upper and lower sides of the outer cylinder (3), a pressure sensor (12) is installed in the second oil port (17).

2. The frame-mounted landing gear passive frame positioner of claim 1, wherein, The end of the plunger (4) close to the connector (15) and the outer cylinder (3) form a cavity C, a first communication hole is formed on the outer wall of the end of the outer cylinder (3) close to the connector (15), the first communication hole is communicated with the cavity C and the atmosphere, a plug cap (10) is installed in the first communication hole.

3. The frame-mounted landing gear passive frame positioner of claim 2, wherein, A T-shaped exhaust hole is formed in the plug cap (10).

4. The frame-mounted landing gear passive frame positioner of any one of claims 1-3, wherein, The damping member (5) is a damping ring, and the damping ring has a damping hole in the center.

5. The frame-mounted landing gear passive frame positioner of any one of claims 1-3, wherein, A three-way joint (11) is installed on the joint (1), an inflation valve (13) and a pressure sensor (12) are respectively installed on the three-way joint (11).

6. The frame-mounted landing gear passive frame positioner of any one of claims 1-3, wherein, The limiting member is a screw sleeve (6).

7. A method of oiling a passive bogie positioner of a landing gear bogie as claimed in any one of claims 1 to 6, characterised in that The following steps are included: S1. The frame positioner is placed vertically with the joint upward, and the hydraulic oil filling device is used to slowly fill oil through the first oil port until the oil fills the second oil port. At this time, the top of the B1 cavity may store air; S2. The frame positioner is inverted with the joint upward, and the frame positioner is shaken to promote the discharge of gas in the B1 cavity; S3. The frame positioner is placed horizontally with the second oil port at the top, and the frame positioner is shaken to promote the floating of the discharged gas in the B1 cavity to the B3 cavity between the outer cylinder and the piston rod; S4. The frame positioner is placed vertically with the joint upward, and the frame positioner is shaken to promote the floating of the gas in the B3 cavity to the vicinity of the second oil port, and then the second oil port is opened to supplement the oil and discharge the gas.

8. The method of claim 7, wherein, The liquid level line of the second oil port is higher than the oil cavity liquid level in the B3 cavity.

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