A landing gear telescopic limiting device, a telescopic limiting method and a helicopter landing gear

Abstract

The application discloses a landing gear telescopic limiting device, a telescopic limiting method and a helicopter landing gear. In the telescopic limiting device, an outer cylinder is divided into two cavities by an integrated partition plate arranged in the middle part. An upper floating piston is arranged in the upper cavity, and the upper cavity is divided into an upper oil cavity and a lower oil cavity by the upper floating piston. The upper floating piston is threadedly connected with the bottom end of a piston rod, the top end of the piston rod extends out of the upper oil cavity, and a sealing end cover is arranged at the end of the upper oil cavity. A lower floating piston is arranged in the lower cavity, and the lower cavity is divided into an upper oil storage cavity and a lower air cavity by the lower floating piston. The air cavity is communicated with the outside air. An oil liquid conducting passage is arranged between the upper oil cavity, the lower oil cavity and the oil storage cavity, and an oil liquid control passage is arranged between the upper oil cavity and the lower oil cavity. The technical scheme provided by the application solves the problems that the existing telescopic limiting device of the helicopter landing gear is difficult to disassemble, the disassembly time is long, and the device is easily damaged.

Description

Technical Field

[0001] This invention relates to, but is not limited to, the field of helicopter landing gear technology, and specifically to a landing gear telescopic limit device, telescopic limit method, and helicopter landing gear. Background Technology

[0002] When helicopters are on a ship, whether on the flight deck or in the hangar, they must have complete and comprehensive mooring measures and supporting equipment to prevent movement or rollover when the ship is rolling and swaying. Among these, the landing gear extension and restraint device is an essential safety feature that limits the extension or retraction of the helicopter's landing gear, ensuring that the helicopter does not pitch or bounce while moored on the deck, effectively protecting the helicopter's structure and equipment. Landing gear extension and restraint devices should also be used in other scenarios that may affect the helicopter's attitude to ensure that the extension of the landing gear buffers does not change under load.

[0003] The main structure of the existing helicopter landing gear telescopic limit device adopts a threaded rod connection. This type of telescopic limit device is prone to thread lock-up when the landing gear is subjected to high tensile or compressive loads. Since it is difficult to determine whether the load is tensile or compressive, helicopter ground crew generally spend a long time and find it difficult to disassemble the telescopic limit device, which can easily damage the device. These problems greatly affect the helicopter's sortie efficiency and mission effectiveness. Summary of the Invention

[0004] The purpose of this invention is to solve the above-mentioned problems. This invention provides a landing gear telescopic limit device, a telescopic limit method, and a helicopter landing gear to solve the problems of existing helicopter landing gear telescopic limit devices, which have threaded rod connection forms that can lock under high loads, and make it difficult to determine the type of load. As a result, the telescopic limit device is difficult to disassemble, takes a long time to disassemble, and is easily damaged.

[0005] The technical solution of the present invention: The embodiment of the present invention provides a landing gear telescopic limiting device, including: an outer cylinder 1, a piston rod 2, an upper floating piston 5, a lower floating piston 6, and a sealing end cap 7;

[0006] The outer cylinder 1 is divided into upper and lower cavities by an integrated partition in the middle. The upper cavity is equipped with an upper floating piston 5, which divides the upper cavity into an upper oil cavity 14 and a lower oil cavity 15. The upper floating piston 5 is threaded to the bottom end of the piston rod 2, and the top end of the piston rod 2 extends out of the upper oil cavity 14. A sealing end cap 7 is installed at the end of the upper oil cavity 14. The lower cavity is equipped with a lower floating piston 6, which divides the lower cavity into an upper oil storage cavity 16 and a lower air cavity. The air cavity is connected to the outside atmosphere.

[0007] An oil passage is provided between the upper oil chamber 14, the lower oil chamber 15 and the oil storage chamber 16, and an oil control passage is provided between the upper oil chamber 14 and the lower oil chamber 15.

[0008] Optionally, in the landing gear telescopic limit device described above,

[0009] The landing gear telescopic limit device is used to control the direction of oil flow between the upper oil chamber 14 and the lower oil chamber 15 through the oil control passage, so as to drive the upper floating piston 5 to move downward or upward, thereby controlling the length of the landing gear telescopic limit device; it is also used to store the oil overflowing from the lower oil chamber 15 or replenish the lower oil chamber 15 through the oil conduction passage during the downward or upward movement of the upper floating piston 5.

[0010] Optionally, in the landing gear telescopic limit device described above,

[0011] The oil control passage includes: a first valve 9 located on the upper part of the upper oil chamber 14 and a second valve 10 located on the lower oil chamber 15, for connecting the oil pipelines of the first valve 9 and the second valve 10, and a rotary hand pump 8 is provided in the oil pipeline. By rotating the hand pump 8 in both directions, the direction of oil flow between the upper oil chamber 14 and the lower oil chamber 15 is controlled.

[0012] Optionally, in the landing gear telescopic limit device described above, the rotary hand pump 8 is configured as an eccentric rotating shaft structure, including: a hand pump housing 18, a hand pump end cover 19, a rotating handle 20, a rotor 21, and blades 22.

[0013] The hand-cranked pump housing 18 is configured as a sleeve structure with one open end and has an eccentric cavity. The opening is sealed by the hand-cranked pump end cover 19. A limiting groove is provided in the middle of the rotor 21, and two blades 22 are installed in the limiting groove of the rotor 21. The mounting structure of the rotor 21 and the two blades 22 is placed in the eccentric cavity as a whole. The two blades 22 isolate the eccentric cavity into a cavity that communicates with the upper oil cavity 14 and a cavity that communicates with the lower oil cavity 15. The rotor shaft of the rotor 21 is connected to the rotating handle 20, and the rotor 21 is driven to rotate in the eccentric cavity by rotating the handle 20.

[0014] Optionally, in the landing gear telescopic limit device described above,

[0015] The rotary hand pump 8 is used to drive the rotor 21 and blades 22 to rotate synchronously in the eccentric cavity by rotating the handle 20, thereby controlling the direction of oil flow between the upper oil chamber 14 and the lower oil chamber 15.

[0016] Optionally, in the landing gear telescopic limit device described above,

[0017] The rotor 21's shaft is located at the eccentric position of the eccentric cavity and is concentric with the outer wall of the hand pump housing 18;

[0018] Two blades 22 are provided with spring mounting holes at their opposite ends. Springs are installed in the spring mounting holes on both sides at the corresponding positions so that the two blades 22 are pushed against the inner wall of the eccentric cavity by the springs so that the blades 22 are in close contact with the inner wall of the eccentric cavity, thereby drawing in and pushing out oil.

[0019] Optionally, in the landing gear telescopic limit device described above,

[0020] The oil flow path includes: a third valve 11 located at the upper part of the upper oil chamber 14, a fourth valve 12 located at the lower part of the lower oil chamber 15, a fifth valve 13 located at the oil storage chamber 16, and an oil pipeline for connecting the third valve 11, the fourth valve 12 and the fifth valve 13.

[0021] This invention provides a method for limiting the extension and retraction of a landing gear telescopic limit device. The method is performed using the landing gear telescopic limit device as described in any of the above claims, and includes: an extension adjustment control method and a retraction adjustment control method.

[0022] The extension adjustment control method includes: by controlling the opening and closing of each valve and the rotation direction of the rotating handle 20, oil is allowed to enter the lower oil chamber 15 from the upper oil chamber 14, pushing the upper floating piston 5 and piston rod 2 to extend, thereby enabling the landing gear extension limit device to extend; during the extension adjustment process, oil is replenished to the lower oil chamber 15 through the oil storage chamber 16.

[0023] The shortening adjustment control method includes: by controlling the opening and closing of each valve and the rotation direction of the rotating handle 20, the oil enters the upper oil chamber 14 from the lower oil chamber 15, pushing the upper floating piston 5 and piston rod 2 to retract, thereby causing the landing gear extension limit device to shorten; during the shortening adjustment process, excess oil enters the oil storage chamber 16 from the upper oil chamber 14.

[0024] Optionally, the telescopic limiting method of the landing gear telescopic limiting device described above further includes: a length locking control method and a length unlocking control method;

[0025] The length locking control method includes: controlling all valves to remain closed, preventing the oil in each oil chamber from flowing and becoming incompressible, thereby locking the length of the telescopic limit device, making it incompressible and inextensible;

[0026] The length unlocking control method includes: first, controlling the third valve 11 to open and the fourth valve 12 to open, so that the upper oil chamber 14 and the lower oil chamber 15 are connected; then controlling the fifth valve 13 to open, so that the upper oil chamber 14 and the lower oil chamber 15 are simultaneously connected to the oil storage chamber 16, and the oil storage chamber 16 is connected to the outside atmosphere through the vent 17.

[0027] This invention also provides a helicopter landing gear, characterized in that it includes: landing gear, upper connector 3, lower connector 4, and landing gear telescopic limiting device as described in any of the above claims;

[0028] The piston rod 2 of the landing gear telescopic limit device is threadedly connected to the upper connector 3, and the upper connector 3 is fixedly connected to the upper position interface of the landing gear; the outer cylinder 1 of the landing gear telescopic limit device is threadedly connected to the lower connector 4, the lower connector 4 is fixedly connected to the lower position interface of the landing gear, and the lower connector 4 is provided with a vent hole 17 for connecting the air cavity with the outside atmosphere.

[0029] The landing gear telescopic limit device is used to control the extension, shortening, length locking, and length unlocking of the landing gear connected to it.

[0030] The beneficial effects of this invention are:

[0031] This invention provides a landing gear telescopic limiting device, a telescopic limiting method, and a helicopter landing gear. The telescopic limiting device's length is adjusted using hydraulic control; an integrated rotary hand pump allows for bidirectional adjustment of the hydraulic flow; a dedicated oil storage chamber stores or replenishes oil in the upper and lower oil chambers; an air chamber connects to the outside atmosphere; and a separate valve controls the locking length of the telescopic limiting device, making it incompressible and non-stretchable. Using the telescopic limiting device provided by this invention, the length of the helicopter landing gear buffer can be limited, making it incompressible and non-stretchable. The length of the telescopic limiting device can be easily adjusted bidirectionally without the need for a special wrench, and the device can be quickly disassembled after being loaded. Attached Figure Description

[0032] The accompanying drawings are provided to further understand the technical solutions of the present invention and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of the present invention and do not constitute a limitation on the technical solutions of the present invention.

[0033] Figure 1This is a schematic diagram of the external structure of the landing gear telescopic limiting device provided in an embodiment of the present invention; Figure 1 In the diagram, b is the front view, a is the left view, and c is the right view.

[0034] Figure 2 for Figure 1 A cross-sectional schematic diagram of the landing gear telescopic limiting device provided in the embodiment shown;

[0035] Figure 3 This is a partially enlarged schematic diagram of the rotary hand pump in the landing gear telescopic limiting device provided in an embodiment of the present invention;

[0036] Figure 4 for Figure 3 A schematic diagram of the internal rotor and blade installation structure of the rotary hand pump provided in the embodiment shown;

[0037] Figure 5 for Figure 3 A schematic diagram of the internal blades of the rotary hand pump provided in the embodiment shown;

[0038] Figure 6 for Figure 3 The illustrated embodiment provides a schematic diagram of the rotor rotating to different positions in a rotary hand-cranked pump. Figure 6 Figure a shows the rotor and blades, while figures b through e show only the rotor. Figure b shows the horizontal position of the rotor, figure c is a 3D view of figure b, figure d shows the vertical position of the rotor, and figure e is a 3D view of figure d. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0040] As explained in the background section, existing helicopter landing gear telescopic limit devices, due to their main structure using threaded rod connections, are prone to thread lock-up under high loads, and it is difficult to determine the type of load. Therefore, helicopter ground crew typically spend a long time and find it difficult to disassemble the telescopic limit device, which can easily damage the device. These problems significantly affect helicopter sortie efficiency and mission effectiveness.

[0041] To address the aforementioned issues, embodiments of the present invention provide a landing gear telescopic limit device, a telescopic limit method, and a helicopter landing gear. By employing hydraulic control of the telescopic limit device's length, the device's own load can be quickly unloaded during disassembly, avoiding thread lock-up problems and significantly reducing maintenance operation time for ground crew.

[0042] The present invention provides the following specific embodiments, which can be combined with each other. For the same or similar concepts or processes, they may not be described again in some embodiments.

[0043] Figure 1 This is a schematic diagram of the external structure of the landing gear telescopic limiting device provided in an embodiment of the present invention; Figure 1 In the diagram, b is the front view, a is the left view, and c is the right view. Figure 2 for Figure 1 A cross-sectional schematic diagram of the landing gear telescopic limiting device provided in the illustrated embodiment. (Refer to...) Figure 1 and Figure 2 As shown, the components of the landing gear telescopic limiting device provided in this embodiment of the invention include: outer cylinder 1, piston rod 2, upper floating piston 5, lower floating piston 6, and sealing end cap 7.

[0044] like Figure 2 The diagram illustrates the internal structure of the landing gear telescopic limit device. The outer cylinder 1 is divided into upper and lower chambers by an integrated partition in the middle. An upper floating piston 5 is installed in the upper chamber, which divides the upper chamber into an upper oil chamber 14 and a lower oil chamber 15. The upper floating piston 5 is threaded to the bottom end of the piston rod 2, and the top end of the piston rod 2 extends out of the upper oil chamber 14. A sealing end cap 7 is installed at the end of the upper oil chamber 14. A lower floating piston 6 is installed in the lower chamber, which divides the lower chamber into an upper oil storage chamber 16 and a lower air chamber. The air chamber is connected to the outside atmosphere.

[0045] like Figure 2 As shown, in the landing gear telescopic limiting device provided in this embodiment of the invention, an oil conduction passage is provided between the upper oil chamber 14, the lower oil chamber 15, and the oil storage chamber 16, such as... Figure 2 The oil passage is located on the left side of the outer cylinder 1; additionally, an oil control passage is provided between the upper oil chamber 14 and the lower oil chamber 15, such as... Figure 2 Oil passage on the right side of the inner and outer cylinder 1.

[0046] Based on the structural form of the landing gear telescopic limiting device provided in the above embodiments of the present invention, the working principle of the landing gear telescopic limiting device is as follows:

[0047] On the one hand, the direction of oil flow between the upper oil chamber 14 and the lower oil chamber 15 is controlled by the oil control passage to drive the upper floating piston 5 to move downward or upward, thereby controlling the length of the landing gear telescopic limit device.

[0048] On the other hand, through the oil passage, during the downward or upward movement of the upper floating piston 5, the oil storage chamber 16 stores the oil overflowing from the lower oil chamber 15 or replenishes the lower oil chamber 15 with oil.

[0049] In one implementation of this invention, such as Figure 2 As shown, the oil control passage includes: a first valve 9 located at the upper part of the upper oil chamber 14, a second valve 10 located at the lower part of the lower oil chamber 15, an oil pipeline for connecting the first valve 9 and the second valve 10, and a rotary hand pump 8 installed in the oil pipeline.

[0050] In this implementation, the direction of oil flow between the upper oil chamber 14 and the lower oil chamber 15 is controlled by rotating the hand pump 8 in both the forward and reverse directions.

[0051] Figure 3 This is a partially enlarged schematic diagram of the rotary hand pump in the landing gear telescopic limiting device provided in an embodiment of the present invention. Figure 4 for Figure 3 The illustrated embodiment provides a schematic diagram of the internal rotor and blade installation structure of a rotary hand-cranked pump. Figure 5 for Figure 3 A schematic diagram of the internal blades of the rotary hand-cranked pump provided in the illustrated embodiment. Figures 3 to 5 As shown, in a specific implementation of this embodiment of the invention, the rotary hand pump 8 is configured as an eccentric rotating shaft structure, including: a hand pump housing 18, a hand pump end cover 19, a rotating handle 20, a rotor 21, and blades 22.

[0052] Reference Figures 3 to 5 As shown, the hand-cranked pump housing 18 is configured as a sleeve structure with one open end and an eccentric cavity. The opening is sealed by the hand-cranked pump end cover 19. A limiting groove is provided in the middle of the rotor 21, and two blades 22 are installed in the limiting groove of the rotor 21. The mounting structure of the rotor 21 and the two blades 22 is placed as a whole in the eccentric cavity. The two blades 22 isolate the eccentric cavity into a cavity communicating with the upper oil cavity 14 and a cavity communicating with the lower oil cavity 15. The rotor 21 shaft is connected to the rotating handle 20, and the rotor 21 is driven to rotate in the eccentric cavity by rotating the handle 20. Figure 6 As shown, Figure 3 The illustrated embodiment provides a schematic diagram of the rotor rotating to different positions in a rotary hand-cranked pump. Figure 6 Figure a shows the rotor and blades, while figures b through e show only the rotor. Figure b shows the horizontal position of the rotor, figure c is a 3D view of figure b, figure d shows the vertical position of the rotor, and figure e is a 3D view of figure d.

[0053] like Figure 4 and Figure 6As shown, the shaft of rotor 21 is located at the eccentric position of the eccentric cavity and is concentric with the outer wall of the hand pump housing 18; the two blades 22 are provided with spring mounting holes at their opposite ends, and springs are installed in the spring mounting holes on both sides at the corresponding positions, so that the two blades 22 are pushed against the inner wall of the eccentric cavity by the springs, so that the blades 22 are in close contact with the inner wall of the eccentric cavity, thereby sucking in and pushing out oil.

[0054] In one implementation of this invention, such as Figure 2 As shown, the oil flow path includes: a third valve 11 located at the upper part of the upper oil chamber 14, a fourth valve 12 located at the lower part of the lower oil chamber 15, a fifth valve 13 located at the oil storage chamber 16, and an oil pipeline for connecting the third valve 11, the fourth valve 12 and the fifth valve 13.

[0055] In specific implementation of this invention, by controlling the opening and closing states of the above-mentioned valves and the rotation direction of the rotating handle 20, the flow direction of the oil between the upper oil chamber 14 and the lower oil chamber 15 can be controlled, thereby driving the upper floating piston 5 to move downward or upward, thereby controlling the length of the landing gear telescopic limit device; it can also realize the length locking function of the telescopic limit device, and realize the length unlocking function of the telescopic limit device by controlling the opening sequence of the valves. The implementation of the above functions is specifically described in the following embodiments.

[0056] The landing gear telescopic limiting device provided in this invention uses hydraulic control to adjust the length of the telescopic limiting device; it employs an integrated rotary hand pump to achieve bidirectional adjustment of the hydraulic flow direction; it uses a dedicated oil storage chamber to store or replenish oil in the upper and lower oil chambers; it uses an air chamber to connect to the outside atmosphere; and it uses a separate valve to control the locking length of the telescopic limiting device, making it incompressible and non-stretchable. Using the telescopic limiting device provided in this invention, the length of the helicopter landing gear buffer can be limited, making it incompressible and non-stretchable. The length of the telescopic limiting device can be easily adjusted bidirectionally without the need for a special wrench, and the device can also be quickly disassembled after being loaded.

[0057] Based on the landing gear telescopic limiting device provided in the above embodiments of the present invention, the present invention also provides a telescopic limiting method performed using the landing gear telescopic limiting device provided in any of the above embodiments, specifically including:

[0058] 1. Extension adjustment control method: By controlling the opening and closing of each valve and the rotation direction of the rotating handle 20, oil is allowed to enter the lower oil chamber 15 from the upper oil chamber 14, pushing the upper floating piston 5 and piston rod 2 to extend, thereby enabling the landing gear extension limit device to extend and adjust; during the extension adjustment process, oil is replenished to the lower oil chamber 15 through the oil storage chamber 16.

[0059] 2. Shortening adjustment control method: By controlling the opening and closing of each valve and the rotation direction of the rotating handle 20, the oil enters the upper oil chamber 14 from the lower oil chamber 15, pushing the upper floating piston 5 and piston rod 2 to retract, thereby causing the landing gear extension limit device to shorten and adjust; during the shortening adjustment process, excess oil enters the oil storage chamber 16 from the upper oil chamber 14.

[0060] 3. Length locking control method: All valves are kept closed, and the oil in each oil chamber cannot flow and cannot be compressed, thereby locking the length of the telescopic limit device, making it incompressible and non-stretchable.

[0061] 4. Length unlocking control method: First, control the third valve 11 to open and control the fourth valve 12 to open, so that the upper oil chamber 14 and the lower oil chamber 15 are connected; then control the fifth valve 13 to open, so that the upper oil chamber 14 and the lower oil chamber 15 are simultaneously connected to the oil storage chamber 16, and the oil storage chamber 16 is connected to the outside atmosphere through the vent 17.

[0062] Based on the landing gear telescopic limiting device and telescopic limiting method provided in the above embodiments of the present invention, the present invention also provides a helicopter landing gear, including: landing gear, upper connector 3, lower connector 4, and landing gear telescopic limiting device as provided in any of the above embodiments.

[0063] The piston rod 2 of the landing gear telescopic limit device is threadedly connected to the upper connector 3, and the upper connector 3 is fixedly connected to the upper position interface of the landing gear; the outer cylinder 1 of the landing gear telescopic limit device is threadedly connected to the lower connector 4, the lower connector 4 is fixedly connected to the lower position interface of the landing gear, and the lower connector 4 is provided with a vent hole 17 for connecting the air cavity with the outside atmosphere.

[0064] The landing gear telescopic limit device is used to control the extension, shortening, length locking, and length unlocking of the landing gear connected to it.

[0065] The specific control methods for elongation adjustment control, shortening adjustment control, length locking control, and length unlocking control have been described in detail in the above embodiments, and therefore will not be repeated here.

[0066] The following is a schematic description of the implementation of a landing gear telescopic limiting device and its telescopic limiting method provided by an embodiment of the present invention through a specific example.

[0067] Example 1

[0068] This embodiment provides an easily detachable helicopter landing gear telescopic limit device. The length of the telescopic limit device is controlled by hydraulic fluid, enabling extension adjustment, shortening adjustment, length locking, and unlocking functions.

[0069] The landing gear telescopic limiting device provided in this embodiment comprises: an outer cylinder 1, a piston rod 2, an upper connector 3, a lower connector 4, an upper floating piston 5, a lower floating piston 6, a sealing end cap 7, a rotary hand pump 8, a first valve 9, a second valve 10, a third valve 11, a fourth valve 12, a fifth valve 13, an upper oil chamber 14, a lower oil chamber 15, an oil storage chamber 16, and a vent 17; wherein the rotary hand pump 8 is composed of a hand pump housing 18, a hand pump end cap 19, a rotating handle 20, a rotor 21, and blades 22.

[0070] In the landing gear telescopic limiting device provided in this embodiment, the upper connector 3 is connected to the piston rod 2 by a threaded structure, and the upper connector 3 can be fixedly connected to the upper position interface of the landing gear; the lower connector 4 is connected to the bottom end of the outer cylinder 1 by a threaded structure, and the lower connector 4 can be fixedly connected to the lower position interface of the landing gear. The lower connector 4 is provided with a vent hole 17, which can connect the cavity below the lower floating piston 6 to the outside atmosphere, preventing the formation of a force on the lower floating piston 6 inside the cavity; the lower end of the piston rod 2 is connected to the upper floating piston 5 by a thread; an integrated partition is designed in the middle of the outer cylinder 1 to separate the lower oil chamber 15 from the oil storage chamber 16; the upper end of the outer cylinder 1 is sealed by a sealing end cover 7, and the outer and inner sides of the sealing end cover 7 are respectively designed with sealing ring grooves, which can be used to install sealing rings and gaskets, so as to isolate the upper oil chamber 14 from the outside atmosphere; the upper floating piston 5 is also provided with a sealing ring groove, which can be used to install sealing rings and gaskets, so as to isolate the upper oil chamber 14 from the lower oil chamber 15.

[0071] In the landing gear telescopic limiting device provided in this embodiment, the upper oil chamber 14 is equipped with two valves, a first valve 9 and a third valve 11; the lower oil chamber 15 is equipped with two valves, a second valve 10 and a fourth valve 12; and the oil storage chamber 16 is equipped with one valve, a fifth valve 13. The third valve 11, the fourth valve 12, and the fifth valve 13 are directly connected via connecting pipes; the first valve 9 and the second valve 10 are connected via connecting pipes, with a rotary hand pump 8 installed in the middle of the pipes.

[0072] In the landing gear telescopic limiting device provided in this embodiment, the upper oil chamber 14, the lower oil chamber 15 and the oil storage chamber 16 are filled with hydraulic oil. The direction of oil flow is controlled by a rotary hand pump 8. The oil pushes and controls the upper floating piston 5 to move up and down, thereby changing the volume of the upper oil chamber 14 and the lower oil chamber 15, so that the telescopic limiting device can be extended or shortened.

[0073] Furthermore, the oil reservoir 16 is designed to store oil overflowing from the lower oil chamber 15 or to replenish oil to the lower oil chamber 15. It should be noted that because the upper oil chamber 14 contains the piston rod 2, its cross-sectional area is smaller than that of the lower oil chamber 15. Therefore, in one scenario, when the upper floating piston 5 moves downwards, the increase in volume of the upper oil chamber 14 is less than the decrease in volume of the lower oil chamber 15, meaning the oil overflowing from the lower oil chamber 15 needs to be stored in the oil reservoir 16. In another scenario, when the upper floating piston 5 moves upwards, the decrease in volume of the upper oil chamber 14 is less than the increase in volume of the lower oil chamber 15, meaning the lower oil chamber 15 needs to be replenished with oil through the oil reservoir 16.

[0074] In the landing gear telescopic limiting device provided in this embodiment, the rotary hand pump 8 adopts an eccentric shaft structure. The pump chamber has two oil inlets and outlets at the top and bottom. The rotor 21 shaft is located eccentrically within the pump chamber, and a limiting groove is designed in the middle of the rotor 21. Two blades 22 are confined within the limiting groove of the rotor 21 and are connected by two springs at opposite ends of the blades 22, ensuring tight contact between the blades 22 and the pump chamber wall, thereby drawing in and expelling oil. The rotary handle 20 can rotate in both directions; clockwise rotation causes oil to flow from the bottom to the upper pipeline, and counterclockwise rotation causes oil to flow from the upper to the lower pipeline.

[0075] The landing gear telescopic limit device provided in this embodiment performs the following functions:

[0076] 1. Extension Adjustment Function: Control the third valve 11 to close, control the fourth valve 12 to open, control the third valve 11 to open, control the first valve 9 to open, control the second valve 10 to open, control the rotating handle 20 to rotate counterclockwise, so that oil enters the lower oil chamber 15 from the upper oil chamber 14, pushing the upper floating piston 5 and piston rod 2 to extend, thereby adjusting the extension limit device of the landing gear; and replenish the lower oil chamber 15 with oil through the oil storage chamber 16. After adjustment, close all valves.

[0077] 2. Shortening Adjustment Function: Control the opening of the third valve 11, the closing of the second valve 10, the opening of the fifth valve 13, the opening of the first valve 9, the opening of the second valve 10, and the clockwise rotation of the rotary handle 20, so that the oil flows from the lower oil chamber 15 into the upper oil chamber 14, pushing the upper floating piston 5 and piston rod 2 to retract, thereby shortening the landing gear extension limit device; in addition, excess oil flows from the upper oil chamber 14 into the oil storage chamber 16, and all valves are closed after the adjustment is in place.

[0078] 3. Length locking function: Controls all valves to remain closed, preventing the oil in the oil chamber from flowing and becoming incompressible, thereby locking the length of the telescopic limit device so that it cannot be compressed or stretched.

[0079] 4. Length Unlock Function: First, control the opening of the third valve 11 and the fourth valve 12. At this time, the upper oil chamber 14 and the lower oil chamber 15 are connected, which can release part of the internal stress tensile load or compressive load. After the third valve 11 and the fourth valve 12 are opened, control the opening of the fifth valve 13. At this time, the upper oil chamber 14 and the lower oil chamber 15 are simultaneously connected to the oil storage chamber 16, which is connected to the outside atmosphere through the vent 17. At this time, the internal stress of the entire telescopic limit device is completely released, the axial load tensile load or compressive load is zero, the telescopic limit function fails, thus realizing the rapid disassembly of the telescopic limit device after being loaded.

[0080] It should be noted that in this length unlocking function, if the third valve 11 and the fifth valve 13 are connected first, or the fourth valve 12 and the fifth valve 13 are connected first, the entire telescopic limit device will directly lose its extension limiting function. At this time, the internal stress of the landing gear under load will be completely released, which may cause a sudden change in the landing gear attitude, resulting in aircraft pitch. Therefore, the internal stress needs to be released gradually to mitigate the possible attitude change.

[0081] While the embodiments disclosed in this invention are as described above, they are merely illustrative of the embodiments to facilitate understanding of the invention and are not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and variations in the form and details of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection for this invention shall still be determined by the scope defined in the appended claims.

Claims

1. A landing gear telescopic limiting device, characterized in that, include: Outer cylinder (1), piston rod (2), upper floating piston (5), lower floating piston (6) and sealing end cap (7); The outer cylinder (1) is divided into upper and lower cavities by an integrated partition in the middle. An upper floating piston (5) is provided in the upper cavity, which divides the upper cavity into an upper oil cavity (14) and a lower oil cavity (15). The upper floating piston (5) is threaded to the bottom end of the piston rod (2), and the top end of the piston rod (2) extends out of the upper oil cavity (14). A sealing end cap (7) is installed at the end of the upper oil cavity (14). A lower floating piston (6) is provided in the lower cavity, which divides the lower cavity into an upper oil storage cavity (16) and a lower air cavity. The air cavity is connected to the outside atmosphere. Among them, an oil conduction passage is provided between the upper oil chamber (14), the lower oil chamber (15) and the oil storage chamber (16), and an oil control passage is provided between the upper oil chamber (14) and the lower oil chamber (15); The oil control passage includes: a first valve (9) located at the upper part of the upper oil chamber (14) and a second valve (10) located in the lower oil chamber (15) for connecting the oil pipeline of the first valve (9) and the second valve (10), and a rotary hand pump (8) is provided in the oil pipeline. The direction of oil flow between the upper oil chamber (14) and the lower oil chamber (15) is controlled by rotating the rotary hand pump (8) in both the forward and reverse directions. The rotary hand pump (8) is configured with an eccentric shaft structure, including: a hand pump housing (18), a hand pump end cover (19), a rotary handle (20), a rotor (21), and blades (22). The hand pump housing (18) is a sleeve structure with one open end and an eccentric cavity. The opening is sealed by the hand pump end cover (19). A limiting groove is provided in the middle of the rotor (21). Two blades (22) are installed in the limiting groove of the rotor (21). The installation structure of the rotor (21) and the two blades (22) is placed in the eccentric cavity. The two blades (22) isolate the eccentric cavity into a cavity that communicates with the upper oil cavity (14) and a cavity that communicates with the lower oil cavity (15). The rotor (21) shaft is connected to the rotating handle (20). The rotor (21) is driven to rotate in the eccentric cavity by the rotating handle (20).

2. The landing gear telescopic limiting device according to claim 1, characterized in that, The landing gear telescopic limit device is used to control the direction of oil flow between the upper oil chamber (14) and the lower oil chamber (15) through the oil control passage, so as to drive the upper floating piston (5) to move downward or upward, thereby controlling the length of the landing gear telescopic limit device; it is also used to store the oil overflowing from the lower oil chamber (15) in the oil storage chamber (16) or replenish the lower oil chamber (15) through the oil conduction passage during the downward or upward movement of the upper floating piston (5).

3. The landing gear telescopic limiting device according to claim 1, characterized in that, The rotary hand pump (8) is used to drive the rotor (21) and blades (22) to rotate synchronously in the eccentric cavity by rotating the handle (20), thereby controlling the direction of oil flow between the upper oil chamber (14) and the lower oil chamber (15).

4. The landing gear telescopic limiting device according to claim 3, characterized in that, The rotor (21) has its shaft located at the eccentric position of the eccentric cavity and is concentric with the outer wall of the hand pump housing (18); Two blades (22) are provided with spring mounting holes at their opposite ends. Springs are installed in the spring mounting holes on both sides at the corresponding positions so that the two blades (22) are pushed against the inner wall of the eccentric cavity by the springs so that the blades (22) are in close contact with the inner wall of the eccentric cavity, thereby drawing in and pushing out oil.

5. The landing gear telescopic limiting device according to any one of claims 1 to 4, characterized in that, The oil passage includes: a third valve (11) located at the upper part of the upper oil chamber (14), a fourth valve (12) located at the lower part of the lower oil chamber (15), a fifth valve (13) located in the oil storage chamber (16), and an oil pipeline for connecting the third valve (11), the fourth valve (12) and the fifth valve (13).

6. A method for limiting the extension and retraction of a landing gear extension and retraction limit device, characterized in that, The method for performing telescopic limiting using the landing gear telescopic limiting device as described in any one of claims 1 to 5 includes: an elongation adjustment control method and a shortening adjustment control method; The extension adjustment control method includes: by controlling the opening and closing of each valve and the rotation direction of the rotating handle (20), the oil enters the lower oil chamber (15) from the upper oil chamber (14), pushing the upper floating piston (5) and piston rod (2) to extend, thereby enabling the landing gear extension limit device to extend; during the extension adjustment process, the lower oil chamber (15) is replenished with oil through the oil storage chamber (16); The shortening adjustment control method includes: by controlling the opening and closing of each valve and the rotation direction of the rotating handle (20), the oil enters the upper oil chamber (14) from the lower oil chamber (15), pushing the upper floating piston (5) and piston rod (2) to retract, thereby enabling the landing gear extension limit device to shorten; during the shortening adjustment process, excess oil enters the oil storage chamber (16) from the upper oil chamber (14).

7. The telescopic limiting method of the landing gear telescopic limiting device according to claim 6, characterized in that, Also includes: Length lock control method, length unlock control method; The length locking control method includes: controlling all valves to remain closed, preventing the oil in each oil chamber from flowing and becoming incompressible, thereby locking the length of the telescopic limit device, making it incompressible and inextensible; The length unlocking control method includes: first, controlling the third valve (11) to open, controlling the fourth valve (12) to open, so that the upper oil chamber (14) and the lower oil chamber (15) are connected; then controlling the fifth valve (13) to open, so that the upper oil chamber (14) and the lower oil chamber (15) are simultaneously connected to the oil storage chamber (16), and the oil storage chamber (16) is connected to the outside atmosphere through the vent (17).

8. A helicopter landing gear, characterized in that, include: Landing gear, upper connector (3), lower connector (4), and landing gear telescopic limiting device as described in any one of claims 1 to 5; The piston rod (2) of the landing gear telescopic limit device is threadedly connected to the upper connector (3), and the upper connector (3) is fixedly connected to the upper position interface of the landing gear; the outer cylinder (1) of the landing gear telescopic limit device is threadedly connected to the lower connector (4), the lower connector (4) is fixedly connected to the lower position interface of the landing gear, and the lower connector (4) is provided with a vent hole (17) for connecting the air cavity with the outside atmosphere; The landing gear telescopic limit device is used to control the extension, shortening, length locking, and length unlocking of the landing gear connected to it.

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