Variable air plug type buffer strut and strut type undercarriage

Abstract

The invention provides a variable air plug type buffering supporting column and a supporting column type undercarriage, and belongs to the technical field of undercarriage design. An inner cylinder in the variable air plug type buffering supporting column is installed in an outer cylinder; the throttle valve is fixed on the inner cylinder; inner cavities of the outer cylinder and the inner cylinder are air cavities; the piston rod is assembled in the outer cylinder through a supporting sleeve, an extension limiting cylinder and a supporting ring from top to bottom, the supporting ring is a spherical joint bearing, the extension limiting cylinder supports the supporting sleeve, and the supporting sleeve and the supporting ring support the piston rod in the upper and lower positions; the supporting sleeve limits the piston rod through the limiting nut, and all the assembled assemblies are integrally fixed and limited through the fixing nut. After the buffering supporting column is compressed for a stroke, the boss makes contact with the lower end face of the supporting sleeve, and the piston rod drives the supporting sleeve to move together. The clamping stagnation phenomenon of the buffer supporting column of the outward-falling supporting column type landing gear can be improved, and the design requirement of the outward-falling supporting column type landing gear is met.

Description

Technical Field

[0001] The invention belongs to the technical field of landing gear design, and in particular relates to a variable air-plug type buffer strut and a strut type landing gear. Background Art

[0002] The landing gear system is one of the important systems of the helicopter. Its main function is to absorb the impact energy during the landing and ground maneuvers of the helicopter. The key component of the landing gear is the buffer strut. The helicopter landing gear is mainly divided into strut landing gear, rocker arm landing gear and semi-rocker arm landing gear. Among them, the strut landing gear is widely used in the field of helicopter landing gear design because of its relatively simple structure, flexible retraction mechanism and light weight. The disadvantages of the strut landing gear are that the buffer strut needs to bear bending load, the friction of the supporting part is large and the sealing design is difficult.

[0003] Currently, narrow-fuselage helicopter strut-type landing gear mostly adopts an outward-slanting design to ensure that there is sufficient lateral wheelbase between the main landing gears on both sides of the helicopter to reduce the risk of fuselage rollover. The existence of the outward angle further worsens the working environment of the strut-type landing gear buffer strut. The additional bending moment will cause the buffer strut to get stuck, resulting in inconsistent compression of the buffer strut or even no compression of the buffer strut, which affects the helicopter's mission completion. Summary of the invention

[0004] In order to solve the technical problem that the compression amount of the buffer strut is inconsistent or even the buffer strut is not compressed due to the outward-leaning design of the strut-type landing gear in the prior art, the present invention proposes a variable air-plug type buffer strut and a strut-type landing gear, which can improve the stuck phenomenon of the buffer strut of the outward-leaning strut-type landing gear and adapt to the design requirements of the outward-leaning strut-type landing gear. The technical solution is as follows:

[0005] In the first aspect, a variable gas plug type buffer support is provided, comprising: an inner tube 3, a throttle valve 5, a piston rod 6, an elongation limiting tube 8, a support sleeve 10, an outer tube 12, and a support ring 16.

[0006] The inner cylinder 3 is installed in the outer cylinder 12; the throttle valve 5 is fixed on the inner cylinder 3; the inner cavity of the outer cylinder 12 and the inner cylinder 3 is the air cavity 4;

[0007] The piston rod 6 is assembled in the outer tube 12 through the support sleeve 10, the elongation limiting tube 8 and the support ring 16 from top to bottom. The support ring 16 is a spherical joint bearing. The elongation limiting tube 8 supports the support sleeve 10. The support sleeve 10 and the support ring 16 support the piston rod 6 at the upper and lower parts, and play a guiding role for the piston rod 6. The support sleeve 10 limits the piston rod 6 through the limit nut (11). After assembly, the components are fixed and limited as a whole through the fixing nut 14.

[0008] The piston rod 6 is provided with a boss 61. After the buffer pillar is compressed for a certain stroke, the boss 61 contacts the lower end surface of the support sleeve 10, and the piston rod 6 drives the support sleeve 10 to move together.

[0009] Among them, during the static compression process of the buffer strut,

[0010] For the front stroke, the movement process of the buffer strut is as follows: the piston rod 6 moves and compresses the air chamber 4, the boss 61 on the piston rod 6 does not contact the lower end surface of the support sleeve 10, the support sleeve 10 remains stationary, and the gas resistance acts on the piston rod 6. At this time, the effective gas plug diameter is the outer diameter of the piston rod 6. Since the gas plug area is small, the starting load of the buffer strut is small and the gas resistance increases slowly. The purpose of starting the buffer strut can be achieved under the action of a small external load, reducing the phenomenon that the buffer strut is easily stuck during the starting stage.

[0011] Among them, during the static compression process of the buffer strut,

[0012] For the rear stroke, the movement process of the buffer strut is as follows: when the piston rod 6 moves to the point where the boss 61 contacts the lower end surface of the support sleeve 10, the gas resistance acts on the support sleeve 10 and the piston rod 6. At this time, the effective gas plug diameter is the outer diameter of the support sleeve 10. Due to the increase in the gas plug area, the gas resistance suddenly changes. When the load continues to increase, the piston rod 6 drives the support sleeve 10 to move together and continues to compress the air cavity 4. The gas resistance continues to act on the support sleeve 10 and the piston rod 6. The gas plug area is increased relative to the initial stage, and the gas resistance increases at a faster rate. By increasing the gas load, the use stroke required for the buffer strut to absorb energy is shortened, thereby meeting the performance requirements of the buffer strut to absorb landing energy.

[0013] Among them, when the buffer pillar is deformed under load, the outer ring and the inner ring at the support ring 16 rotate relative to each other, releasing the internal force formed by the stiffness difference between the outer tube 12 and the piston rod 6. The surface contact between the outer ring and the inner ring can ensure sufficient support area, greatly reducing the additional friction of the buffer pillar caused by the stiffness difference, and alleviating the phenomenon that the buffer pillar is easy to get stuck during the startup stage.

[0014] Optionally, a plurality of lubrication nozzles 13 are installed on the outer side of the lower end of the outer cylinder 12 and close to the support ring 16 for injecting grease to lubricate the support ring 16 , which can improve the use environment of the support ring 16 and further increase the service life of the support ring 16 .

[0015] Optionally, a plastic support ring and a rubber sealing ring are arranged inside the support sleeve 10; the outer ring material of the support ring 16 is alloy structural steel, and the inner ring material is copper alloy, which can play a better guiding role for the piston rod 6.

[0016] Optionally, there is an oil chamber 7 inside the piston rod (6). When the buffer strut is working, the piston rod 6 moves along the inner tube 3 under the support of the support sleeve 10 and the support ring 16, and the oil enters the air chamber 4 through the throttle valve 5, generating oil damping force while compressing the air chamber 4.

[0017] Optionally, an air filling nozzle 2 is installed at the upper end of the outer cylinder 12 for injecting hydraulic oil into the oil chamber 7 and filling nitrogen into the air chamber 4 .

[0018] Optionally, the inner cylinder 3 is installed in the outer cylinder 12 by means of bolts 1 ; and the throttle valve 5 is fixed to the inner cylinder 3 by means of pins 9 .

[0019] In a second aspect, a strut-type landing gear is provided, comprising a variable air-plug-type buffer strut as described in any one of the first aspects.

[0020] The beneficial effects of the present invention are at least:

[0021] The variable gas plug type buffer strut of the present invention adopts an oil-gas hybrid configuration, and reduces the additional friction of the buffer strut caused by the difference in stiffness between the piston rod and the outer cylinder through the support design of the spherical joint bearing type support ring. The variable gas plug design reduces the starting load of the buffer strut while optimizing the use stroke to meet the use requirements of the helicopter. The variable gas plug type buffer strut of the present invention can improve the stuck phenomenon of the buffer strut of the outward-leaning strut landing gear, and is adapted to the design requirements of the outward-leaning strut landing gear. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the overall structure of the buffer support of the present invention;

[0023] Figure 2 It is a schematic diagram of the movement of the front stroke of the buffer support;

[0024] Figure 3 It is a schematic diagram of the movement of the rear section of the buffer support;

[0025] Figure 4 Schematic diagram of the static pressure curve of the buffer pillar. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below through specific implementation modes and drawings.

[0027] An embodiment of the present invention provides a variable air plug type buffer support, which is composed of Figure 1 As shown, it is composed of a bolt (1), an inflation nozzle (2), an inner tube (3), a throttle valve (5), a piston rod (6), an elongation limiting tube (8), a pin (9), a support sleeve (10), a limit nut (11), an outer tube (12), a lubrication nozzle (13), a fixing nut (14), a lubrication nozzle (15), and a support ring (16).

[0028] The inner cylinder (3) is installed in the outer cylinder (12) by means of bolts (1), the throttle valve (5) is fixed to the inner cylinder (3) by means of pins (9), and the internal cavities of the outer cylinder (12) and the inner cylinder (3) are air cavities (4).

[0029] The piston rod (6) is assembled in the outer cylinder (12) layer by layer through the support sleeve (10), the elongation limiting cylinder (8) and the support ring (16). The elongation limiting cylinder (8) supports the support sleeve (10). The support sleeve (10) limits the position of the piston rod (6) through the limit nut (11). The fixing nut (14) fixes and limits the assembled components as a whole. The support sleeve (10) and the support ring (16) support the piston rod (6) at the upper and lower positions.

[0030] A boss (61) is designed on the piston rod (6). After the buffer pillar is compressed for a certain stroke, the boss (61) contacts the lower end surface of the support sleeve (10), driving the support sleeve (10) to move together.

[0031] A plastic support ring and a rubber sealing ring are arranged inside the support sleeve (10); the support ring (16) is a spherical joint bearing with an outer ring made of alloy structural steel and an inner ring made of copper alloy, and is used to better guide the piston rod (6).

[0032] Two lubrication nozzles (13) are installed on the outer side of the lower end of the outer cylinder (12) for regularly injecting grease to lubricate the support ring (16), so as to improve the use environment of the support ring (16) and thus increase the service life of the support ring (16).

[0033] The piston rod (6) contains an oil chamber (7). When the buffer support is working, the piston rod (6) moves along the inner cylinder (3) under the support of the support sleeve (10) and the support ring (16). The oil enters the air chamber (4) through the throttle valve (5), generates oil damping force and compresses the air chamber (4). In the present invention, an air filling nozzle (2) is installed at the upper end of the outer cylinder (12) for injecting hydraulic oil into the oil chamber (7) and nitrogen into the air chamber (4).

[0034] The static compression process of the buffer strut is as follows:

[0035] 1) The movement process of the front stroke buffer support is as follows Figure 2 As shown, the piston rod (6) moves to compress the air chamber (4), the boss (61) on the piston rod (6) does not contact the support sleeve (10), the support sleeve (10) remains stationary, and the gas resistance acts on the piston rod (6). At this time, the effective gas plug diameter is the outer diameter of the piston rod (6). The static pressure curve at this stage is as shown in FIG. Figure 4As shown in the middle AB section, due to the small area of ​​the gas plug, the starting load of the buffer pillar is small and the gas resistance increases slowly. The purpose of starting the buffer pillar can be achieved under the action of a small external load, reducing the phenomenon that the buffer pillar is easy to get stuck during the starting stage;

[0036] 2) The movement process of the buffer support in the rear stroke is as follows Figure 3 As shown, when the piston rod (6) moves to the point where the boss (61) contacts the lower end surface of the support sleeve (10), the gas resistance acts on the support sleeve (10) and the piston rod (6). At this time, the effective gas plug diameter is the outer diameter of the support sleeve (10). As the gas plug area increases, the gas resistance suddenly changes, as shown in FIG. Figure 4 As shown in the BC section. When the load continues to increase, the piston rod (6) drives the support sleeve (10) to move together and continue to compress the air chamber (4). The static pressure curve at this stage is as follows Figure 4 As shown in the middle CD section, the gas resistance continuously acts on the support sleeve (10) and the piston rod (6), increasing the gas plug area relative to the initial stage, and the gas resistance increases at a faster rate. By increasing the gas load, the use stroke required for the buffer strut to absorb energy is shortened, thereby meeting the performance requirements of the buffer strut to absorb landing energy.

[0037] In the front and rear strokes, when the buffer pillar is deformed under load, the outer ring and the inner ring at the support ring (16) rotate relative to each other, releasing the internal force formed by the stiffness difference between the outer tube (12) and the piston rod (6). Compared with the line contact in the prior art, the surface contact between the outer ring and the inner ring can ensure a sufficient support area and greatly reduce the additional friction of the buffer pillar caused by the stiffness difference.

[0038] The embodiment of the present invention provides an assembly process of a variable air plug type buffer support, see Figure 1 , including the following steps:

[0039] Step 1: Use a pin (9) to fix the throttle valve (5) at a corresponding position on the inner tube (3);

[0040] Step 2: Install the inner cylinder (3) into the corresponding position of the outer cylinder (12), install the bolts (1) and tighten them to fix the inner cylinder (3);

[0041] Step 3: Sleeve the support sleeve (10) onto the piston rod (6);

[0042] Step 4: Install the limit nut (11) on the top of the piston rod (6) and tighten it;

[0043] Step 5: Install the piston rod (6) into the outer cylinder (12), and sleeve the piston rod (6) onto the inner cylinder (3);

[0044] Step 6: Sleeve the elongation limiting cylinder (8) and the support ring (16) onto the piston rod (6) and install them into the outer cylinder (12);

[0045] Step 7: Sleeve the fixing nut (14) onto the piston rod (6) and insert it into the outer tube (12), and tighten the fixing nut (14) to achieve overall fixing and limiting of the assembled components;

[0046] Step 8, installing the inflation nozzle (2) and the lubrication nozzle (13) on the outer cylinder (12);

[0047] Step 9, inflate and inject oil into the buffer support through the inflation nozzle (2);

[0048] Step 10: Lubricate the support ring (16) through the lubrication nozzle (13).

[0049] In summary, the advantages of the present invention are as follows:

[0050] 1) The upper part of the piston rod is supported by a plastic ring, and the lower part is supported by a spherical bearing with outer steel and inner copper, which can improve the additional friction of the buffer pillar caused by the difference in stiffness and reduce the phenomenon that the outward-leaning pillar landing gear is easy to get stuck under the action of ground load;

[0051] 2) A lubrication nozzle is provided as the lubrication interface of the lower spherical bearing support, which can improve the working environment of the spherical bearing support and increase the product life;

[0052] 3) The design of the variable air plug reduces the starting load of the buffer strut, alleviating the problem of the outward-leaning strut landing gear being easily stuck during the starting phase;

[0053] 4) The upper support of the piston rod is designed to have the function of air plug compression. In the latter part of the working stroke of the buffer support, it compresses the gas together with the piston rod, which increases the gas resistance and shortens the use stroke of the buffer support;

[0054] 5) The boss on the piston rod is designed as a trigger structure for switching the gas plug area. The gas plug size can be automatically adjusted during the operation of the buffer support, and the structure is simple.

[0055] The above only expresses the implementation mode of the present invention, and its description is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. In addition, the parts not detailed in the present invention are all conventional technologies.

Claims

1. A variable air plug type buffer support, characterized in that: include: Inner cylinder (3), throttle valve (5), piston rod (6), elongation limiting cylinder (8), support sleeve (10), outer cylinder (12), support ring (16), The inner cylinder (3) is installed in the outer cylinder (12); the throttle valve (5) is fixed on the inner cylinder (3); the inner cavities of the outer cylinder (12) and the inner cylinder (3) are air cavities (4); The piston rod (6) is assembled in the outer cylinder (12) through a support sleeve (10), an elongation limiting cylinder (8) and a support ring (16) from top to bottom. The support ring (16) is a spherical joint bearing. The elongation limiting cylinder (8) supports the support sleeve (10). The support sleeve (10) and the support ring (16) support the piston rod (6) at two locations, upper and lower. The support sleeve (10) limits the position of the piston rod (6) through a limiting nut (11). After assembly, the components are fixed and limited as a whole through a fixing nut (14). The piston rod (6) is provided with a boss (61). After the buffer pillar is compressed for a certain stroke, the boss (61) contacts the lower end surface of the support sleeve (10), and the piston rod (6) drives the support sleeve (10) to move together.

2. The buffer pillar according to claim 1, characterized in that: During the static compression of the buffer strut, For the front stroke, the movement process of the buffer support is as follows: the piston rod (6) moves and compresses the air chamber (4), the boss (61) on the piston rod (6) does not contact the lower end surface of the support sleeve (10), the support sleeve (10) remains stationary, and the gas resistance acts on the piston rod (6). At this time, the effective gas plug diameter is the outer diameter of the piston rod (6). Since the gas plug area is small, the starting load of the buffer support is small and the gas resistance increases slowly. The purpose of starting the buffer support can be achieved under the action of a small external load, reducing the phenomenon that the buffer support is easily stuck during the starting stage.

3. The buffer pillar according to claim 2, characterized in that: During the static compression of the buffer strut, For the rear stroke, the movement process of the buffer strut is as follows: when the piston rod (6) moves to the point where the boss (61) contacts the lower end surface of the support sleeve (10), the gas resistance acts on the support sleeve (10) and the piston rod (6). At this time, the effective gas plug diameter is the outer diameter of the support sleeve (10). As the gas plug area increases, the gas resistance changes suddenly. When the load continues to increase, the piston rod (6) drives the support sleeve (10) to move together and continues to compress the air cavity (4). The gas resistance continues to act on the support sleeve (10) and the piston rod (6). The gas plug area is increased relative to the initial stage, and the gas resistance increases at a faster rate. By increasing the gas load, the use stroke required for the buffer strut to absorb energy is shortened, thereby meeting the performance requirements of the buffer strut to absorb landing energy.

4. The buffer pillar according to claim 2 or 3, characterized in that: When the buffer pillar is deformed under load, the outer ring and the inner ring at the support ring (16) rotate relative to each other, releasing the internal force formed by the stiffness difference between the outer tube (12) and the piston rod (6). The surface contact between the outer ring and the inner ring can ensure sufficient support area.

5. The buffer pillar according to claim 1, characterized in that: A plurality of lubrication nozzles (13) are installed on the outer side of the lower end of the outer cylinder (12) and close to the support ring (16) for injecting lubricating grease to lubricate the support ring (16).

6. The buffer pillar according to claim 1, characterized in that: A plastic support ring and a rubber sealing ring are arranged inside the support sleeve (10); the outer ring material of the support ring (16) is alloy structural steel, and the inner ring material is copper alloy.

7. The buffer pillar according to claim 1, characterized in that: The piston rod (6) contains an oil chamber (7). When the buffer support is in operation, the piston rod (6) moves along the inner tube (3) under the support of the support sleeve (10) and the support ring (16), and the oil enters the air chamber (4) through the throttle valve (5), generating an oil damping force while compressing the air chamber (4).

8. The buffer pillar according to claim 1, characterized in that: An air filling nozzle (2) is installed at the upper end of the outer cylinder (12) for injecting hydraulic oil into the oil chamber (7) and nitrogen into the air chamber (4).

9. The buffer pillar according to claim 1, characterized in that: The inner cylinder (3) is installed in the outer cylinder (12) by means of bolts (1); the throttle valve (5) is fixed on the inner cylinder (3) by means of a pin (9).

10. A strut-type landing gear, characterized in that: It comprises a variable air plug type buffer strut as described in any one of claims 1 to 9.

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