Undercarriage buffer sealing structure and assembling method

Abstract

The invention provides an undercarriage buffer sealing structure and an assembling method. The undercarriage buffer sealing structure comprises an outer cylinder (1), a piston rod (2), a supporting sleeve (4), a first clamping ring (10), a check ring (11) and a second clamping ring (12). The head of the piston rod (2) is inserted into the outer cylinder (1) from the first end, and the outer side of the rod part of the piston rod (2) is sleeved with a supporting sleeve (4); the outer side of the supporting sleeve (4) is further sleeved with a check ring (11) and a second clamping ring (12). And the first clamping ring (10) and the second clamping ring (12) are used for limiting the axial movement of the supporting sleeve (4). The problem that the ultra-high-strength steel sealing structure is not suitable for being connected in a threaded mode is effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of buffers, and in particular to a landing gear buffer sealing structure and an assembly method. Background Art

[0002] The landing gear is a device located at the bottom of an airplane or helicopter to support the body and absorb landing energy. The buffer is the core component of the landing gear to achieve buffering and energy absorption, and is usually of oil-gas configuration. The oil-gas buffer compresses the buffer piston rod to compress the internal gas to generate air spring force, so that the oil passes through the throttle hole to generate oil damping force, thereby achieving the buffering and energy absorption function. During the buffer compression process, the pressure inside the buffer gradually increases and can reach tens of MPa. How to seal high-pressure oil and gas is a key issue to be solved in the buffer seal design.

[0003] The buffer is composed of multiple cylinders of different diameters, which are sleeved together to form the various cavities of the buffer, and the cavities need to be sealed. The seals of the buffer can be divided into three types: fixed seals, sliding seals and rotary seals, among which sliding seals and rotary seals are also called active seals. Due to the long-term relative movement of the active seal, in addition to considering the sealing problem, the friction problem between the cylinders must also be solved.

[0004] In recent years, ultra-high strength steel has been increasingly used in landing gear. Due to their high strength, these materials are prone to fatigue problems. When designing the buffer structure, it is necessary to avoid using threaded connections. This also brings great challenges to the design of the buffer structure.

[0005] Conventional methods use threaded connections to achieve a movable sealing structure for the buffer. In order to avoid fatigue problems caused by threads in structures using ultra-high-strength steel, a threadless sealing structure needs to be designed. Summary of the invention

[0006] The invention provides a landing gear buffer sealing structure and an assembly method, which is a threadless sealing structure.

[0007] A first aspect of the present invention provides a landing gear buffer sealing structure, comprising: an outer tube 1, a piston rod 2, a support sleeve 4, a first clamping ring 10, a retaining ring 11 and a second clamping ring 12;

[0008] The first end of the outer tube 1 is provided with an inner diameter enlarged section;

[0009] The head of the piston rod 2 is inserted into the outer tube 1 from the first end and passes through the inner diameter increasing section.

[0010] A support sleeve 4 is sleeved on the outer side of the piston rod 2.

[0011] The middle part of the outer side of the support sleeve 4 has an annular boss, which is matched with the inner wall of the inner diameter enlargement section with a small gap.

[0012] A first annular groove is provided in the inner diameter enlarged section; a first clamping ring 10 is provided in the first annular groove, and the first clamping ring 10 is sleeved on the outside of the support sleeve 4 and located on the outside of the annular boss; a retaining ring 11 and a second clamping ring 12 are also sleeved on the outside of the support sleeve 4;

[0013] A second annular groove is provided on the outer side of the first end of the support sleeve 4; the second clamping ring 12 is clamped in the second annular groove and fits on the outer end surface of the first end of the outer tube 1, and the first clamping ring 10 and the second clamping ring 12 are used to limit the axial movement of the support sleeve 4;

[0014] An annular cavity is formed between the annular boss of the support sleeve 4, the second end head and the inner diameter enlarged section, and the length of the annular cavity is L; the length of the annular cavity is greater than the length from the annular boss of the support sleeve 4 to the first end head.

[0015] Optionally, the landing gear buffer sealing structure further includes: a first support ring 3;

[0016] A third annular groove is arranged outside the head of the piston rod 2 , and a first support ring 3 is installed inside the third annular groove. One side of the first support ring 3 fits with the inner wall of the outer tube 1 , and the other side fits with the outer wall of the third annular groove on the piston rod 2 .

[0017] Optionally, the landing gear buffer sealing structure further includes: a fixed sealing ring 5;

[0018] A groove is arranged outside the first end of the support sleeve 4, and a fixed sealing ring 5 is arranged in the groove. One side of the fixed sealing ring 5 is in contact with the inner wall of the outer tube 1, and the other side is in contact with the outer wall of the groove.

[0019] Optionally, the landing gear buffer sealing structure further includes: a fixed sealing protection ring 6;

[0020] A fixed sealing protection ring 6 is also provided in the groove;

[0021] The fixed sealing protection ring 6 is arranged on the outer end surface of the fixed sealing ring 5 .

[0022] Optionally, the landing gear buffer sealing structure further includes: a second support ring 9;

[0023] A fourth annular groove is provided inside the support sleeve 4 , and a second support ring 9 is installed inside the fourth annular groove. One side of the second support ring 9 fits against the outer wall of the piston rod 2 , and the other side fits against the inner wall of the fourth annular groove on the support sleeve 4 .

[0024] Optionally, the landing gear buffer sealing structure further includes: a movable sealing ring 7;

[0025] Two movable sealing rings 7 are also arranged inside the support sleeve 4 .

[0026] Optionally, the landing gear buffer sealing structure further includes: a movable sealing protection ring 8;

[0027] A movable sealing protection ring 8 is also arranged on the inner side of the support sleeve 4 , and the movable sealing protection ring 8 is arranged on the outer end surface of the movable sealing ring 7 .

[0028] Optionally, the landing gear buffer sealing structure further includes: a dust ring;

[0029] A dust ring is provided on the mating surface between the outer side of the support sleeve 4 and the piston rod 2 .

[0030] A second aspect of the present invention provides an assembly method for a landing gear buffer sealing structure as described in any one of the first aspects, comprising:

[0031] Put the support sleeve 4 on the piston rod 2;

[0032] Push the support sleeve 4 and the piston rod 2 into the outer tube 1 to expose the first annular groove for installing the first clamping ring 10, and install the first clamping ring 10;

[0033] Inflate the landing gear buffer from the inflation nozzle of the piston rod 2 to extend the piston rod 2 outward, thereby driving the support sleeve 4 to extend outward until it contacts the first clamping ring 10;

[0034] A retaining ring 11 and a second clamping ring 12 are installed on the supporting sleeve 4 .

[0035] The present invention proposes a landing gear buffer sealing structure and assembly method, which is a sealing structure without threaded connection and its assembly method, which effectively solves the problem that ultra-high strength steel sealing structures are not suitable for threaded connection. It can avoid the fatigue problem of ultra-high strength steel caused by the threaded structure and greatly improve the service life of the buffer. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a cross-sectional view of the buffer;

[0037] Figure 2 for Figure 1 AA section view;

[0038] Figure 3 is a schematic diagram of the annular cavity;

[0039] Description of reference numerals:

[0040] Outer tube 1, piston rod 2, first support ring 3, support sleeve 4, fixed sealing ring 5, fixed sealing protection ring 6, movable sealing ring 7, movable sealing protection ring 8, second support ring 9, first clamping ring 10, retaining ring 11, second clamping ring 12, dustproof ring 13 and inflation nozzle 14. DETAILED DESCRIPTION

[0041] The technical solution provided by the present invention is explained below in conjunction with the accompanying drawings.

[0042] The invention provides a landing gear buffer sealing structure and an assembly method.

[0043] like Figure 1-3 As shown, the landing gear buffer sealing structure provided by the present invention includes: an outer tube 1, a piston rod 2, a first support ring 3, a support sleeve 4, a fixed sealing ring 5, a fixed sealing protection ring 6, a movable sealing ring 7, a movable sealing protection ring 8, a second support ring 9, a first clamping ring 10, a retaining ring 11, a second clamping ring 12, a dust ring 13 and an inflation nozzle 14.

[0044] The outer cylinder 1 and the piston rod 2 are the main components of the buffer. One end of the piston rod is inserted into the outer cylinder to form a cavity inside the buffer. When the buffer is working, there is relative movement between the outer cylinder 1 and the piston rod 2. When compressed, the piston rod 2 moves Figure 1 The outer cylinder 1 and the piston rod 2 are filled with oil and gas, and the pressure increases with the compression of the buffer and decreases with the extension of the buffer.

[0045] One end of the piston rod 2 is a head, and a third annular groove is arranged outside the head. A first support ring 3 is installed inside the third annular groove, and one side of the first support ring 3 is in contact with the inner wall of the outer tube 1, and the other side is in contact with the outer wall of the third annular groove on the piston rod 2, so that a certain gap is left between the outer tube 1 and the piston rod 2 to prevent friction between the outer tube 1 and the piston rod 2.

[0046] The support sleeve 4 is used to achieve the sealing between the outer cylinder 1 and the piston rod 2. Figure 3 The inner diameter of one end of the outer tube 1 increases. The support sleeve 4 is installed between the outer tube 1 and the piston rod 2, and one end is matched with the inner wall of the outer tube with a small clearance (D2). The middle part has an annular boss and the inner wall of the outer tube where the inner diameter increases is matched with a small clearance (D1). After installation, an annular cavity is formed between the support sleeve 4 and the outer tube 1, and the length of the annular cavity is L.

[0047] The support sleeve 4 and the outer cylinder 1 are sealed at the matching surface with a diameter of D2 by a fixed sealing ring 5. A fixed sealing protection ring 6 is installed outside the fixed sealing ring 5 to protect the fixed sealing ring 5.

[0048] The support sleeve 4 has a fourth annular groove on the side close to the piston rod 2, and a second support ring 9 is installed inside the fourth annular groove. One side of the second support ring 9 is in contact with the outer wall of the piston rod 2, and the other side is in contact with the inner wall of the fourth annular groove on the support sleeve 4, so that a certain gap is left between the support sleeve 4 and the piston rod 2 to prevent friction between the support sleeve 4 and the piston rod 2. The support sleeve 4 and the piston rod 2 are sealed at the matching surface with a diameter of D3 by two movable sealing rings 7. Movable sealing protection rings 8 are installed on the outside of the movable sealing rings 7 to protect the fixed sealing rings 7.

[0049] The outer cylinder 1 has a first annular groove at the increased inner diameter, and a first clamping ring 10 is installed in the first annular groove. The first clamping ring 10 contacts the boss on the support sleeve 4 to limit the support sleeve from moving outward. The first clamping ring 10 includes three sections.

[0050] There is pressure inside the buffer, and the piston rod 2 will extend outward under the action of the pressure. The annular boss at one end of the piston rod 2 contacts the support sleeve 4 when the piston rod extends outward, which can prevent the piston rod 2 from coming out of the outer tube 1 and play a role of limiting.

[0051] A retaining ring 11 and a second retaining ring 12 are installed on the outside of the first retaining ring 10. The second retaining ring 12 is installed in the second annular groove on the support sleeve 4, and one side contacts the retaining ring 11, which can limit the support sleeve 4 from moving inside the outer tube 1. A dust ring is installed on the outer side of the support sleeve 4 and the mating surface of the piston rod 2 to prevent dust from entering the buffer.

[0052] An air filling nozzle is arranged on the piston rod 2 to fill air into the buffer. By reasonably setting the distance between the boss on the support sleeve 4 and the outer end face of the support sleeve 4, it is made smaller than the length L of the annular cavity formed between the support sleeve 4 and the outer tube 1. When assembling the buffer, first install the sealing ring and the dust ring on the support sleeve 4. Put the support sleeve 4 on the piston rod 2. Push the support sleeve 4 and the piston rod 2 into the outer tube 1 to expose the first annular groove for installing the first clamping ring 10. Install the first clamping ring 10. Inflate the buffer from the air filling nozzle to extend the piston rod 2 outward, thereby driving the support sleeve 4 to extend outward until it contacts the first clamping ring 10. Install the retaining ring 11 and the second clamping ring 12 on the support sleeve.

[0053] The key points of the present invention are as follows:

[0054] By setting an annular cavity between the support sleeve 4 and the outer cylinder 1, the length L of the annular cavity is made greater than the distance between the boss on the support sleeve 4 and the outer end surface of the support sleeve 4. The installation problem of the first clamping ring 10 is solved.

[0055] The first clamp ring 10 is used to limit the movement of the support sleeve 4, and the retaining ring 11 and the second clamp ring 12 are used to limit the movement of the support sleeve 4 inwardly by the first clamp ring 10. The clamp rings are used to simultaneously limit the movement of the support sleeve 4 relative to the outer cylinder 1.

[0056] During the assembly process, the support sleeve 4 is first pushed into the outer tube 1 and the first collar 10 is installed. Then, the support sleeve 4 is moved outward and contacts the first collar 10 by inflating the air cavity.

Claims

1. A landing gear buffer sealing structure, characterized in that: include: An outer cylinder (1), a piston rod (2), a support sleeve (4), a first clamping ring (10), a retaining ring (11) and a second clamping ring (12); The first end of the outer cylinder (1) is provided with an inner diameter enlarged section; The head of the piston rod (2) is inserted into the outer tube (1) from the first end and passes through the inner diameter enlarged section. A support sleeve (4) is sleeved on the outer side of the rod portion of the piston rod (2). The middle part of the outer side of the support sleeve (4) is provided with an annular boss, which is matched with the inner wall of the inner diameter enlarged section with a small gap. A first annular groove is provided in the inner diameter enlarged section; a first clamping ring (10) is provided in the first annular groove, and the first clamping ring (10) is sleeved on the outside of the support sleeve (4) and located on the outside of the annular boss; a retaining ring (11) and a second clamping ring (12) are also sleeved on the outside of the support sleeve (4); A second annular groove is arranged on the outer side of the first end of the support sleeve (4); the second clamping ring (12) is clamped in the second annular groove and fits on the outer end surface of the first end of the outer cylinder (1); the first clamping ring (10) and the second clamping ring (12) are used to limit the axial movement of the support sleeve (4); An annular cavity is formed between the annular boss of the support sleeve (4), the second end head and the inner diameter enlarged section, and the length of the annular cavity is L; the length of the annular cavity is greater than the length from the annular boss of the support sleeve (4) to the first end head.

2. The landing gear buffer sealing structure according to claim 1, characterized in that: Also includes: A first support ring (3); A third annular groove is arranged on the outside of the head of the piston rod (2), and a first support ring (3) is installed inside the third annular groove. One side of the first support ring (3) is in contact with the inner wall of the outer tube (1), and the other side is in contact with the outer wall of the third annular groove on the piston rod (2).

3. The landing gear buffer sealing structure according to claim 1, characterized in that: Also includes: Fixed sealing ring (5); A groove is arranged on the outer side of the first end of the support sleeve (4), and a fixed sealing ring (5) is arranged in the groove. One side of the fixed sealing ring (5) is in contact with the inner wall of the outer cylinder (1), and the other side is in contact with the outer wall of the groove.

4. The landing gear buffer sealing structure according to claim 2, characterized in that: Also includes: A fixed sealing protection ring (6); A fixed sealing protection ring (6) is also arranged in the groove; The fixed sealing protection ring (6) is arranged on the outer end surface of the fixed sealing ring (5).

5. The landing gear buffer sealing structure according to claim 1, characterized in that: Also includes: A second supporting ring (9); A fourth annular groove is provided on the inner side of the support sleeve (4), and a second support ring (9) is installed inside the fourth annular groove. One side of the second support ring (9) is in contact with the outer wall of the piston rod (2), and the other side is in contact with the inner wall of the fourth annular groove on the support sleeve (4).

6. The landing gear buffer sealing structure according to claim 1, characterized in that: Also includes: Movable sealing ring (7); Two movable sealing rings (7) are also arranged on the inner side of the support sleeve (4).

7. The landing gear buffer sealing structure according to claim 6, characterized in that: Also includes: Movable sealing protection ring (8); A movable sealing protection ring (8) is also arranged on the inner side of the support sleeve (4), and the movable sealing protection ring (8) is arranged on the outer end surface of the movable sealing ring (7).

8. The landing gear buffer sealing structure according to claim 1, characterized in that: Also includes: Dust ring; A dust ring is provided on the matching surface between the outer side of the support sleeve (4) and the piston rod (2).

9. An assembly method for a landing gear buffer sealing structure according to any one of claims 1 to 8, characterized in that: include: Put the support sleeve (4) on the piston rod (2); Push the support sleeve (4) and the piston rod (2) into the outer tube (1) to expose the first annular groove for installing the first clamping ring (10), and then install the first clamping ring (10); Inflate the landing gear buffer from the inflation nozzle of the piston rod (2) to cause the piston rod (2) to extend outward, thereby driving the support sleeve (4) to extend outward until it contacts the first clamping ring (10); A retaining ring (11) and a second retaining ring (12) are installed on the supporting sleeve (4).

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