An efficient energy-absorbing buffer

Abstract

The present invention belongs to the technical field of helicopter landing gears, and discloses an efficient energy-absorbing buffer, which includes a low-pressure piston rod, an intermediate cylinder and a high-pressure piston rod. The low-pressure piston rod and the high-pressure piston rod are respectively arranged in the holes at both ends of the intermediate cylinder. The chamber between the two holes of the intermediate cylinder is an oil-pressing chamber; the inner cavity of the low-pressure piston rod facing outwards is a low-pressure air chamber, and the inner cavity of the low-pressure piston rod facing the intermediate cylinder is a low-pressure oil return chamber. The low-pressure oil return chamber and the low-pressure air chamber are separated by a low-pressure chamber floating piston, and the low-pressure oil return chamber is communicated with the oil-pressing chamber through a low-pressure chamber throttle valve assembly; the inner cavity of the high-pressure piston rod facing outwards is a high-pressure air chamber, and the inner cavity of the high-pressure piston rod facing the intermediate cylinder is a high-pressure oil return chamber. The high-pressure air chamber and the high-pressure oil return chamber are separated by a high-pressure chamber floating piston, and the high-pressure oil return chamber is communicated with the oil-pressing chamber through a high-pressure chamber throttle valve assembly. The present invention maximally improves the efficiency of the buffer. During the landing shock process, the pressure in the oil return chamber and the pressure in the air chamber are basically the same, which is beneficial to the design of the overload protection device.

Description

Technical Field

[0001] The present invention belongs to the technical field of helicopter landing gears, and relates to a buffer for a helicopter landing gear, in particular to an efficient energy-absorbing buffer. Background Art

[0002] Due to its special rotor structure, a helicopter can achieve vertical hovering. Therefore, civil helicopters are mostly used for urban medical treatment and forest fire fighting and are often in a state of ultra-low altitude flight. The flight environments in cities, forests, and mountains are complex, and helicopters are prone to crashing. Therefore, the use of anti-crash technology is the only way to protect the safety of helicopter crew members.

[0003] As the core component for energy absorption and buffering in the efficient energy-absorbing system of a helicopter, the anti-crash performance of the buffer directly determines the survival ability of the helicopter. At the same time, during the daily use of the buffer, it is required to minimize the landing overload of the helicopter, which makes the operating load of the buffer of the helicopter landing gear in a very large speed range. A helicopter needs an efficient energy-absorbing buffer that can ensure a small overload of the helicopter at low speeds and avoid too high an overload at high speeds. Traditional helicopter landing gears use a two-stage oil-gas buffer. During normal use, the low-pressure chamber is used for energy absorption, and when the landing speed is relatively high, the high-pressure chamber is used for energy absorption.

[0004] When the piston rod of this type of buffer is compressed to the end, the load will increase sharply, posing a great challenge to the design of the airframe structure. In addition, some buffers are provided with an overload protection device, which is designed on the air chamber. During the landing shock process, the air chamber pressure is not stable and the unloading is lagging, which is not conducive to the load design of the landing gear. Summary of the Invention

[0005] Objective of the present invention: To solve the above problems, the present invention provides an efficient energy-absorbing buffer, which adopts a double piston rod design, maximally improves the efficiency of the buffer, and has strong designability.

[0006] Technical solution of the present invention:

[0007] An efficient energy-absorbing buffer includes a low-pressure piston rod, an intermediate cylinder, and a high-pressure piston rod. The low-pressure piston rod and the high-pressure piston rod are respectively arranged in the holes at both ends of the intermediate cylinder. The chamber between the two holes of the intermediate cylinder is an oil pressure chamber; the inner cavity of the low-pressure piston rod facing outward is a low-pressure air chamber, the inner cavity of the low-pressure piston rod facing the intermediate cylinder is a low-pressure oil return chamber, and the low-pressure oil return chamber and the low-pressure air chamber are separated by a low-pressure chamber floating piston. The low-pressure oil return chamber is communicated with the oil pressure chamber through a low-pressure chamber throttle valve assembly; the inner cavity of the high-pressure piston rod facing outward is a high-pressure air chamber, the inner cavity of the high-pressure piston rod facing the intermediate cylinder is a high-pressure oil return chamber, and the high-pressure air chamber and the high-pressure oil return chamber are separated by a high-pressure chamber floating piston. The high-pressure oil return chamber is communicated with the oil pressure chamber through a high-pressure chamber throttle valve assembly.

[0008] Further, the initial pressure in the high-pressure air cavity is greater than the initial pressure in the low-pressure air cavity.

[0009] Further, an oil injection nozzle and an exhaust device communicating with the pressure oil cavity are provided on the cylinder wall of the intermediate cylinder.

[0010] Further, an overload protection device is further included. The overload protection device is arranged outside the cavity wall of the low-pressure oil return cavity. When the oil pressure in the low-pressure oil return cavity is greater than a certain limit, the overload protection device connects the external environment and the low-pressure oil return cavity, and the oil in the low-pressure oil return cavity flows out to achieve rapid pressure relief.

[0011] Further, the overload protection device is at least one hollow bolt circumferentially arranged in the low-pressure oil return cavity. The hollow bolt connects the external environment and the low-pressure oil return cavity. A rubber plug is installed at the opening on the side of the external environment of the hollow bolt, and a sealing ring is provided on the contact ring surface between the rubber plug and the hollow bolt.

[0012] Further, a bursting diaphragm is further included. The bursting diaphragm is a spherical thin-wall structure. The bursting diaphragm is arranged on the side of the hollow bolt in the low-pressure oil return cavity to block the inlet and outlet of the hollow bolt.

[0013] Further, a low-pressure inflation nozzle is arranged outside the low-pressure piston rod, and a high-pressure inflation nozzle is arranged outside the high-pressure piston rod.

[0014] Further, the compression process of the buffer is divided into four stages.

[0015] The first stage: The piston rod in the low-pressure cavity moves, compressing the low-pressure air cavity. At the same time, the oil in the pressure oil cavity is compressed and flows into the low-pressure oil return cavity through the low-pressure cavity throttle valve assembly, generating a damping force to absorb the landing energy.

[0016] The second stage: When the buffer is further compressed, the pressure in the pressure oil cavity is greater than the sum of the pressure in the high-pressure oil return cavity and its static friction force. The oil in the pressure oil cavity flows into the high-pressure oil return cavity through the high-pressure cavity throttle valve assembly, generating a damping force. At this time, the high-pressure cavity starts, and the piston rod in the high-pressure cavity moves to further absorb the landing energy.

[0017] The third stage: When the buffer continues to be compressed, the pressure in the low-pressure oil return cavity further increases. After its pressure is greater than the allowable pressure of the overload protection device, the oil in the low-pressure oil return cavity quickly loses through the overload protection device under the action of the pressure in the low-pressure air cavity, and the load of the buffer quickly decreases.

[0018] The fourth stage: The buffer is compressed to the design stroke until it is damaged. After the buffer is damaged, the load of the buffer is the oil damping force generated when the oil flows through the low-pressure cavity throttle valve assembly, and the buffer can still absorb a small part of the landing energy.

[0019] The beneficial effects of the present invention:

[0020] 1. The present invention adopts a double-piston rod design, which maximally improves the efficiency of the buffer;

[0021] 2. The overload protection device of the present invention is designed on the oil return cavity. During the landing shock process, the pressure in the oil return cavity is basically the same as that in the air cavity, and the pressure in the air cavity is only related to the buffer stroke. The input of the overload protection device is clear, which is conducive to the design of the overload protection device;

[0022] 3. After the overload protection device is damaged, the oil in the high-pressure cavity flows from the oil return cavity into the oil pressure cavity under the action of the pressure in the high-pressure air cavity, and the oil in the oil pressure cavity flows out through the oil return cavity, which can quickly reduce the buffer pressure and reduce the destructive force after blasting;

[0023] 4. After the overload protection device is damaged, the buffer continues to compress and can still provide oil damping force to further absorb part of the landing energy;

[0024] 5. Reasonable combination design can be carried out on the oil holes of the throttle valve components in the low-pressure cavity and high-pressure cavity of the buffer, the pressures in the high and low-pressure air cavities, and the breaking load of the overload protection device, so that the buffer finally achieves an energy absorption efficiency far exceeding that of ordinary buffers;

[0025] 6. The blasting diaphragm is a spherical thin-wall structure, which reduces stress concentration and does not affect the normal working performance of the buffer. Moreover, the low-pressure oil return cavity has the lowest pressure within a conventional time compared with other oil cavities, which maximally ensures the service life of the blasting diaphragm. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is the overall schematic diagram of the buffer of the present invention;

[0027] Figure 2 is the schematic diagram of the principle of the buffer of the present invention;

[0028] Figure 3 is the schematic diagram of the principle of the overload protection device of the present invention;

[0029] Among them, 1 - upper joint, 2 - high-pressure piston rod, 3 - intermediate cylinder, 4 - oil injection nozzle, 5 - exhaust device, 6 - overload protection device, 7 - low-pressure piston rod, 8 - low-pressure inflation nozzle, 9 - lower joint, 10 - high-pressure inflation nozzle, 11 - low-pressure air cavity, 12 - low-pressure cavity floating piston, 13 - low-pressure oil return cavity, 14 - low-pressure cavity throttle valve assembly, 15 - oil pressure cavity, 16 - high-pressure cavity throttle valve assembly, 17 - high-pressure oil return cavity, 18 - high-pressure cavity floating piston, 19 - high-pressure air cavity, 20 - overload protection device, 21 - rubber plug, 22 - hollow bolt, 23 - blasting diaphragm, 24 - sealing ring. DETAILED DESCRIPTION OF THE INVENTION

[0030] This part is an embodiment of the present invention, which is used to explain and illustrate the technical solution of the present invention. Without conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0031] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicating directions or positional relationships are the azimuth or positional relationships given according to the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or case referred to must have a specific azimuth, be constructed and operated in a specific azimuth, and therefore cannot be understood as a limitation to the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or the number of technical features implicitly indicated. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include more than one such feature. In the description of the present invention, unless otherwise stated, the meaning of "a plurality" is two or more.

[0032] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", "connected" should be interpreted in a broad sense. For example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or a point connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific situations.

[0033] An efficient energy-absorbing buffer includes a low-pressure piston rod 7, an intermediate cylinder 3 and a high-pressure piston rod 2. The low-pressure piston rod 7 and the high-pressure piston rod 2 are respectively arranged in the holes at both ends of the intermediate cylinder 3. The chamber between the two holes of the intermediate cylinder 3 is the oil pressure chamber 15; the inner cavity of the low-pressure piston rod 7 facing outwards is the low-pressure gas chamber 11, the inner cavity of the low-pressure piston rod 7 facing the intermediate cylinder 3 is the low-pressure oil return chamber 13, and the low-pressure oil return chamber 13 and the low-pressure gas chamber 11 are separated by a low-pressure chamber floating piston 12. The low-pressure oil return chamber 13 is communicated with the oil pressure chamber 15 through a low-pressure chamber throttle valve assembly 14; the inner cavity of the high-pressure piston rod 2 facing outwards is the high-pressure gas chamber 19, the inner cavity of the high-pressure piston rod 2 facing the intermediate cylinder 3 is the high-pressure oil return chamber 17, and the high-pressure gas chamber 19 and the high-pressure oil return chamber 17 are separated by a high-pressure chamber floating piston 18. The high-pressure oil return chamber 17 is communicated with the oil pressure chamber 15 through a high-pressure chamber throttle valve assembly 16.

[0034] The initial pressure in the high-pressure gas chamber 19 is greater than the initial pressure in the low-pressure gas chamber 11.

[0035] An oil injection nozzle 4 and an exhaust device 5 communicating with the oil pressure chamber 15 are provided on the cylinder wall of the intermediate cylinder 3.

[0036] It further includes an overload protection device 20 which is arranged outside the cavity wall of the low-pressure oil return cavity 13. When the oil pressure in the low-pressure oil return cavity 13 is greater than a certain limit, the overload protection device 20 connects the external environment with the low-pressure oil return cavity 13, allowing the oil in the low-pressure oil return cavity 13 to flow out to achieve rapid pressure relief.

[0037] The overload protection device 20 is at least one hollow bolt 22 arranged circumferentially on the low-pressure oil return cavity 13. The hollow bolt 22 connects the external environment with the low-pressure oil return cavity 13. A rubber plug 21 is installed at the opening on the external environment side of the hollow bolt 22, and a sealing ring 24 is provided on the contact ring surface between the rubber plug 21 and the hollow bolt 22.

[0038] It further includes a bursting diaphragm 23 which is a spherical thin-wall structure. The bursting diaphragm 23 is arranged on the side of the hollow bolt 22 in the low-pressure oil return cavity 13 to block the inlet and outlet of the hollow bolt 22.

[0039] A low-pressure inflation nozzle 8 is arranged outside the low-pressure piston rod 7, and a high-pressure inflation nozzle 10 is arranged outside the high-pressure piston rod 2.

[0040] The compression process of the buffer is divided into four stages.

[0041] The first stage: The low-pressure cavity piston rod moves to compress the low-pressure air cavity. At the same time, the oil in the oil compression cavity flows into the low-pressure oil return cavity through the low-pressure cavity throttle valve assembly, generating a damping force to absorb the landing energy.

[0042] The second stage: When the buffer is further compressed, the pressure in the oil compression cavity is greater than the sum of the pressure in the high-pressure oil return cavity and its static friction force. The oil in the oil compression cavity flows into the high-pressure oil return cavity through the high-pressure cavity throttle valve assembly, generating a damping force. At this time, the high-pressure cavity starts, and the high-pressure cavity piston rod moves to further absorb the landing energy.

[0043] The third stage: When the buffer continues to be compressed, the pressure in the low-pressure oil return cavity further increases. After its pressure is greater than the allowable pressure of the overload protection device, the oil in the low-pressure oil return cavity quickly drains through the overload protection device under the action of the pressure in the low-pressure air cavity, and the buffer load quickly decreases.

[0044] The fourth stage: When the buffer is compressed to the designed stroke until it is damaged, after the buffer is damaged, the load of the buffer is the oil damping force generated when the oil flows through the low-pressure cavity throttle valve assembly, and the buffer can still absorb a small part of the landing energy.

[0045] The following further describes another embodiment of the present invention in detail with reference to the accompanying drawings.

[0046] The high-efficiency energy-absorbing buffer proposed by the present invention is composed of a low-pressure piston rod 7, an intermediate cylinder 3, a high-pressure piston rod 2, etc. The low-pressure piston rod 7 is provided with a low-pressure chamber throttle valve assembly 14 and a low-pressure chamber floating piston 12. Through the low-pressure chamber throttle valve assembly 14 and the low-pressure chamber floating piston 12, the buffer cavity is divided into a pressure oil chamber 15, a low-pressure oil return chamber 13, and a low-pressure gas chamber 113 chambers; the high-pressure piston rod is provided with a high-pressure chamber throttle valve assembly 16 and a high-pressure chamber floating piston 18. Through the high-pressure chamber throttle valve assembly 16 and the high-pressure chamber floating piston 18, the buffer cavity is divided into a pressure oil chamber 15, a high-pressure oil return chamber 17, and a high-pressure gas chamber 193 chambers; at the position of the low-pressure oil return chamber 13 at the end of the intermediate cylinder 3, an overload protection device 20 is provided. The overload protection device is composed of a hollow bolt 22, a rubber plug 21, a sealing ring 24, a bursting diaphragm 23, etc. The bursting diaphragm 23 is a spherical thin-wall structure; inflation nozzles 8 and 10 are arranged on the low-pressure piston rod 7 and the high-pressure piston rod 2, and an oil injection nozzle 4 and an exhaust device 5 are arranged on the intermediate cylinder 3.

[0047] When the buffer is compressed, the low-pressure chamber piston rod moves first, compressing the low-pressure gas chamber. At the same time, the oil in the pressure oil chamber is compressed and flows into the low-pressure oil return chamber through the low-pressure chamber throttle valve assembly 14, generating a damping force to absorb the landing energy.

[0048] When the buffer is further compressed, the pressure in the pressure oil chamber is greater than the sum of the pressure in the high-pressure oil return chamber and its starting force (static friction force). The oil in the pressure oil chamber flows into the high-pressure oil return chamber through the high-pressure chamber throttle valve assembly, generating a damping force. At this time, the high-pressure chamber starts, and the high-pressure chamber piston rod moves to further absorb the landing energy.

[0049] When the buffer continues to be compressed, the pressure in the low-pressure oil return chamber further increases. After its pressure is greater than the allowable pressure of the overload protection device, the bursting diaphragm is damaged, and the oil in the low-pressure oil return chamber quickly flows out through the three overload protection devices under the pressure of the low-pressure gas chamber, and the buffer load quickly decreases. The buffer enters the stage of low-load stroke until the buffer is compressed to the designed stroke. After the buffer is damaged, its load does not drop to zero. At this time, the load is the oil damping force generated when the oil flows through the low-pressure chamber throttle valve assembly 14. The buffer can still absorb a small part of the landing energy, making the most of the buffer stroke, and the buffer efficiency is relatively high.

[0050] Using the landing device designed by the present invention, its performance and load design are very convenient, the stroke utilization rate is high, the high-pressure gas chamber can participate in daily energy absorption, the energy absorption efficiency is high, and in the crash condition, the buffer can still provide a certain amount of energy absorption capacity after being damaged, with high energy absorption efficiency and strong designability.

[0051] The above are only specific embodiments of the present invention. The present invention has been described in detail, and the parts not elaborated are conventional technologies. However, the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. The protection scope of the present invention shall be subject to the protection scope of the claims described above.

Claims

1. An efficient energy-absorbing buffer, characterized in that, it includes a low-pressure piston rod (7), an intermediate cylinder (3) and a high-pressure piston rod (2). The low-pressure piston rod (7) and the high-pressure piston rod (2) are respectively arranged in the holes at both ends of the intermediate cylinder (3). The chamber between the two holes of the intermediate cylinder (3) is the oil pressure chamber (15); the inner cavity of the low-pressure piston rod (7) facing outwards is the low-pressure air chamber (11), the inner cavity of the low-pressure piston rod (7) facing the intermediate cylinder (3) is the low-pressure oil return chamber (13), and the low-pressure oil return chamber (13) and the low-pressure air chamber (11) are separated by a low-pressure chamber floating piston (12). The low-pressure oil return chamber (13) is communicated with the oil pressure chamber (15) through a low-pressure chamber throttle valve assembly (14); the inner cavity of the high-pressure piston rod (2) facing outwards is the high-pressure air chamber (19), the inner cavity of the high-pressure piston rod (2) facing the intermediate cylinder (3) is the high-pressure oil return chamber (17), and the high-pressure air chamber (19) and the high-pressure oil return chamber (17) are separated by a high-pressure chamber floating piston (18). The high-pressure oil return chamber (17) is communicated with the oil pressure chamber (15) through a high-pressure chamber throttle valve assembly (16); it also includes an overload protection device (20). The overload protection device (20) is arranged outside the chamber wall of the low-pressure oil return chamber (13). When the oil pressure in the low-pressure oil return chamber (13) is greater than a certain limit, the overload protection device (20) connects the external environment and the low-pressure oil return chamber (13), and allows the oil in the low-pressure oil return chamber (13) to flow out to achieve rapid pressure relief; the overload protection device (20) is at least one hollow bolt (22) circumferentially arranged on the low-pressure oil return chamber (13). The hollow bolt (22) connects the external environment and the low-pressure oil return chamber (13). A rubber plug (21) is installed at the opening on the external environment side of the hollow bolt (22), and a sealing ring (24) is arranged on the contact ring surface between the rubber plug (21) and the hollow bolt (22); it also includes a bursting diaphragm (23). The bursting diaphragm (23) is a spherical thin-wall structure. The bursting diaphragm (23) is arranged on one side of the hollow bolt (22) in the low-pressure oil return chamber (13) and blocks the inlet and outlet of the hollow bolt (22).

2. The efficient energy-absorbing buffer according to claim 1, characterized in that, the initial pressure in the high-pressure air chamber (19) is greater than the initial pressure in the low-pressure air chamber (11).

3. The efficient energy-absorbing buffer according to claim 1, characterized in that, an oil injection nozzle (4) and an exhaust device (5) communicating with the oil pressure chamber (15) are arranged on the cylinder wall of the intermediate cylinder (3).

4. The efficient energy-absorbing buffer according to claim 1, characterized in that, a low-pressure inflation nozzle (8) is arranged outside the low-pressure piston rod (7), and a high-pressure inflation nozzle (10) is arranged outside the high-pressure piston rod (2).

5. The efficient energy-absorbing buffer according to claim 1, characterized in that, the compression process of the buffer is divided into four stages, The first stage: the low-pressure piston rod moves, compressing the low-pressure air chamber. At the same time, the oil in the oil pressure chamber is compressed and flows into the low-pressure oil return chamber through the low-pressure chamber throttle valve assembly, generating a damping force to absorb the landing energy; Second stage: When the buffer is further compressed, the pressure in the oil pressing chamber is greater than the sum of the pressure in the high-pressure oil return chamber and its static friction force. The oil in the oil pressing chamber flows into the high-pressure oil return chamber through the high-pressure chamber throttle valve assembly, generating a damping force. At this time, the high-pressure chamber starts, and the high-pressure piston rod moves to further absorb the landing energy; Third stage: When the buffer continues to be compressed, the pressure in the low-pressure oil return chamber further increases. After its pressure is greater than the allowable pressure of the overload protection device, the oil in the low-pressure oil return chamber quickly drains through the overload protection device under the action of the pressure in the low-pressure air chamber, and the buffer load quickly decreases; Fourth stage: When the buffer is compressed to the designed stroke until it is damaged, after the buffer is damaged, the load of the buffer is the oil damping force generated when the oil flows through the low-pressure chamber throttle valve assembly, and the buffer can still absorb a small part of the landing energy.

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