A special-shaped triangular cross-section sealing structure and hydraulic system

Abstract

The application provides a special triangular cross-section sealing structure and a hydraulic system, which comprises a shell bushing (1), a piston rod (2), an elastomer (3), a sealing ring (4), a triangular check ring (5), an inner concave surface (6), a first lip (7), a second lip (8), a first inclined edge (9), a second inclined edge (10) and a cutout (11). The elastomer (3), the sealing ring (4) and the triangular check ring (5) are sequentially arranged in a sealing groove, the elastomer (3) is close to a high-pressure side, and the triangular check ring (5) is close to a low-pressure side. The sealing ring (4) and the elastomer (3) are in concave-convex cooperation, a protrusion is arranged on an inner ring of the sealing ring (4), and the contact surface of the sealing ring (4) and the triangular check ring (5) is an inclined surface.

Description

Technical Field

[0001] This invention belongs to the field of sealing design technology, and relates to an irregular triangular cross-section sealing structure and a hydraulic system. Background Technology

[0002] Hydraulic seals are a core technology ensuring the safe operation of aircraft; leakage due to seal failure can lead to serious accidents. Currently, aircraft flight control systems heavily rely on hydraulic servo actuators as the actuators for control surface position control. These actuators provide the necessary force and torque for stabilizing and controlling the aircraft through reciprocating motion. Because they use high-pressure hydraulic oil as the working medium, hydraulic servo actuators inevitably suffer from external leakage of the hydraulic medium. With technological advancements, aircraft face increasingly stringent constraints on structural weight and space, leading to continuously increasing hydraulic operating pressure systems. Next-generation actuators, represented by electro-hydraulic actuators (EHA), integrate the oil source and actuator, and their closed hydraulic systems impose extremely stringent external leakage limits.

[0003] Hydraulic reciprocating seals typically employ composite sealing rings with polytetrafluoroethylene (PTFE) as the sealing slip ring. PTFE has a low coefficient of friction and maintains performance stability over a wide temperature range, exhibiting good performance in most hydraulic reciprocating sealing applications. However, for high-pressure operating systems of 35 MPa and above, the strength of PTFE is insufficient to withstand the structural instability, extrusion damage, and wear caused by high medium pressure. Existing sealing structures also face the problem of further increased leakage rates under high pressure.

[0004] In response to the ever-increasing working medium pressure and more stringent leakage control requirements of high-end aviation equipment, innovative designs for sealing structures are needed to meet the sealing requirements of high pressure resistance and low leakage. Summary of the Invention

[0005] This invention proposes an irregular triangular cross-section sealing structure and hydraulic system, which has high pressure resistance and low leakage sealing function, and can achieve structural stability under high medium pressure.

[0006] The present invention proposes an irregular triangular cross-section sealing structure, comprising: a housing bushing 1, a piston rod 2, an elastic body 3, a sealing ring 4, a triangular retaining ring 5, an inner concave surface 6, a first lip 7, a second lip 8, a first inclined side 9, a second inclined side 10, and a cut 11.

[0007] The piston rod 2 is sleeved inside the housing bushing 1, and a sealing groove is provided on the inner side of the housing bushing 1; an elastic body 3, a sealing ring 4 and a triangular retaining ring 5 are arranged sequentially along the axial direction in the sealing groove;

[0008] The elastic body 3 is a ring-shaped structure with a circular cross-section;

[0009] The sealing ring 4 is a circular ring structure with an irregular cross-section. The cross-sectional structure of the sealing ring 4 has an inner concave surface 6, a first lip 7, a second lip 8, a first inclined side 9, and an auxiliary inclined side. The inner concave surface 6, the first lip 7, the second lip 8, the first inclined side 9, and the auxiliary inclined side are connected in sequence to form the irregular cross-section of the sealing ring 4. The inner concave surface 6 is in concave-convex fit with the elastic body 3.

[0010] The triangular retaining ring 5 is a circular structure with an irregular cross-section and has a cut 11; the cross-sectional structure of the triangular retaining ring 5 has a second inclined side 10, which contacts and engages with the first inclined side 9;

[0011] During assembly and operation, the elastomer 3 is close to the high-pressure side, the triangular retaining ring 5 is close to the low-pressure side, and the sealing ring 4 is located between the elastomer 3 and the triangular retaining ring 5.

[0012] The elastic body 3 is in contact with the housing bushing 1 and the sealing ring 4, but the elastic body 3 is not in direct contact with the piston rod 2;

[0013] The sealing ring 4 is in direct contact with the piston rod 2. The first lip 7 and the second lip 8 are located on both sides of the contact area between the sealing ring 4 and the piston rod 2, respectively. The first lip 7 faces the high pressure side, and the second lip 8 faces the low pressure side.

[0014] The angle between the first lip 7 and the axis of the piston rod 2 toward the high-pressure side is an acute angle, and the angle value is the first angle. The angle between the second lip 8 and the axis of the piston rod 2 toward the low-pressure side is an acute angle, and the angle value is the second angle. The first angle is greater than the second angle.

[0015] The angle between the first hypotenuse 9 and the axis of piston rod 2, which faces the low-pressure side, is an acute angle.

[0016] Optionally, the angle between the first inclined side 9 and the axis of the piston rod 2 facing the low-pressure side is greater than 45°.

[0017] Optionally, the angle between the second lip 8 and the axis of the piston rod 2 toward the low-pressure side is less than 30°.

[0018] Optionally, the thickness of the triangular retaining ring 5 at the end facing the bottom of the sealing groove is less than the thickness at the end facing the piston rod 2.

[0019] Optionally, the triangular retaining ring 5 is made of polyetheretherketone (PEEK).

[0020] Optionally, the sealing ring 4 is made of polytetrafluoroethylene.

[0021] Optionally, the elastomer 3 material is rubber.

[0022] Optionally, the sealing ring 4 is interference-fitted with the outer cylindrical surface of the piston rod 2.

[0023] Optionally, the elastomer 3 is interference-fitted with the bottom of the sealing groove of the housing bushing 1.

[0024] The present invention also provides a hydraulic system, comprising: a hydraulic product, wherein the hydraulic product adopts an irregular triangular cross-section sealing structure as described in any of the above claims;

[0025] Hydraulic products are hydraulic actuators or hydraulic mode switching valves.

[0026] This invention proposes an irregularly shaped triangular cross-section sealing structure and hydraulic system. The sealing ring adopts an asymmetric sealing lip structure, which generates a reverse backflow oil film when the piston rod retracts from the low-pressure side to the high-pressure side, offsetting part of the leakage of the medium from the high-pressure side to the low-pressure side, achieving extremely low reciprocating leakage. Polyetheretherketone (PEEK) material is used as the retaining ring to improve the sealing structure's resistance to extrusion damage. The triangular cross-section retaining ring structure can induce a supporting effect under pressure, preventing the sealing ring from collapsing under high medium pressure and ensuring the stability and reliability of the sealing structure under high pressure conditions. This invention solves the problems of increased leakage, structural instability, and extrusion damage in traditional reciprocating sealing structures under high working pressure, providing a novel reciprocating sealing structure with high pressure resistance, low leakage, and high reliability. Attached Figure Description

[0027] Figure 1 This is a cross-sectional schematic diagram of an anisotropic triangular cross-section sealing structure according to the present invention;

[0028] Figure 2 This is a cross-sectional schematic diagram of the sealing ring of the present invention;

[0029] Figure 3 Here is a schematic diagram of the triangular retaining ring of the present invention:

[0030] Explanation of reference numerals in the attached figures:

[0031] Housing bushing-1, piston rod-2, elastomer-3, sealing ring-4, triangular retaining ring-5, concave surface-6, first lip-7, second lip-8, first bevel-9, second bevel-10, cut-11. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] The features and illustrative embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. The invention is by no means limited to any specific setups and methods set forth below, but covers any improvements, substitutions, and modifications to structures, methods, and devices without departing from the spirit of the invention. Well-known structures and techniques are not shown in the drawings and the following description to avoid unnecessarily obscuring the invention.

[0034] It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other, and the various embodiments can be referenced and cited in each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0035] The irregular triangular cross-section sealing structure provided by the present invention will be explained below with reference to the accompanying drawings.

[0036] like Figure 1-3 As shown, the present invention provides an irregular triangular cross-section sealing structure, comprising: a housing bushing 1, a piston rod 2, an elastic body 3, a sealing ring 4, a triangular retaining ring 5, an inner concave surface 6, a first lip 7, a second lip 8, a first inclined side 9, a second inclined side 10, and a cut 11, wherein:

[0037] The inner hole sealing groove of the housing bushing 1 has an elastic body 3, a sealing ring 4 and a triangular retaining ring 5 arranged sequentially along the axial direction;

[0038] During assembly and operation, the elastomer 3 is close to the high-pressure side, the triangular retaining ring 5 is close to the low-pressure side, and the sealing ring 4 is located between the elastomer 3 and the triangular retaining ring 5.

[0039] The elastic body 3 is a ring-shaped structure with a circular cross-section;

[0040] The elastic body 3 is in contact with the housing bushing 1 and the sealing ring 4, but the elastic body 3 is not in direct contact with the piston rod 2;

[0041] The sealing ring 4 is a circular structure with an irregular cross-section;

[0042] The sealing ring 4 has a concave surface 6, a first lip 7, a second lip 8, and a first inclined side 9.

[0043] The concave surface 6 and the elastic body 3 are in a concave-convex fit;

[0044] The sealing ring 4 is in direct contact with the piston rod 2. The first lip 7 and the second lip 8 are located on both sides of the contact area between the sealing ring 4 and the piston rod 2, respectively. The first lip 7 faces the high pressure side, and the second lip 8 faces the low pressure side.

[0045] The angle between the first lip 7 and the axis of the piston rod 2 is an acute angle; the angle between the second lip 8 and the axis of the piston rod 2 is an acute angle and less than 30°; the angle between the first lip 7 and the axis of the piston rod 2 is greater than the angle between the second lip 8 and the axis of the piston rod 2; the angle between the first hypotenuse 9 and the axis of the piston rod 2 is an acute angle and greater than 45°.

[0046] The triangular retaining ring 5 is a circular structure with an irregular cross-section and has a cut 11;

[0047] The triangular retaining ring 5 has a cross-sectional structure with a second inclined side 10, which is in contact with the first inclined side 9.

[0048] The angle between the second hypotenuse 10 and the axis of the piston rod 2 is acute and greater than 45°.

[0049] The elastomer 3 is made of rubber or other elastic material and should provide sufficient resilience after assembly to ensure the sealing of the structure under low pressure.

[0050] The sealing ring 4 is made of polytetrafluoroethylene (PTFE), but is not limited to PTFE. It can also be other plastics or similar materials with low coefficient of friction, which can maintain structural integrity under high pressure and maintain mechanical properties over a wide temperature range.

[0051] The material of the triangular retaining ring 5 is polyetheretherketone (PEEK), but it is not limited to PEEK. It can also be other plastics or other similar materials with low coefficient of friction, high wear resistance, and sufficient strength to withstand high pressure shear and extrusion damage.

[0052] In this invention, the piston rod 2 has a smooth outer cylindrical surface, and the elastic body 3, sealing ring 4, and triangular retaining ring 5 are all annular structures, arranged sequentially along the axial direction in the sealing groove of the inner hole of the housing bushing 1. The elastic body 3 is located near the high-pressure side, in direct contact with the high-pressure medium, and also in direct contact with the housing bushing 1 and sealing ring 4, but not in direct contact with the piston rod 2.

[0053] The sealing ring 4 is located between the elastic body 3 and the triangular retaining ring 5. The concave surface 6 of the sealing ring 4 fits the elastic body 3 to form a tight sealing contact. The sealing ring 4 directly contacts the piston rod 2 to prevent leakage. The first lip 7 and the second lip 8 of the sealing ring 4 are located on both sides of the contact area between the sealing ring 4 and the piston rod 2. The first inclined side 9 of the sealing ring 4 contacts and fits with the triangular retaining ring 5. The triangular retaining ring 5 is located near the low-pressure side to prevent the sealing structure from being squeezed into the gap between the housing bushing 1 and the piston rod 2. Unlike the traditional rectangular cross-section retaining ring, the triangular retaining ring 5 has a second inclined side 10. The angle between the second inclined side 10 and the axis of the piston rod 2 is acute and greater than 45°, and it contacts and fits with the first inclined side 9 of the sealing ring 4. The triangular retaining ring 5 has a cut 11 to prevent it from gripping the piston rod 2.

[0054] When the medium pressure is low, the elastomer 3 provides clamping force through assembly pre-compression, which fits tightly with the housing bushing 1 and the sealing ring 4, and makes the sealing ring 4 fit tightly with the piston rod 2, blocking the leakage channel between the housing bushing 1 and the piston rod 2, ensuring sealing. The elastomer 3, the sealing ring 4 and the triangular retaining ring 5 are squeezed by a small medium pressure difference in the axial direction, so that the first inclined side 9 of the sealing ring 4 and the second inclined side 10 of the triangular retaining ring 5 fit together stably.

[0055] When the medium pressure is high, the elastomer 3 can transmit the medium pressure to generate sufficient sealing contact pressure to ensure sealing. The elastomer 3, sealing ring 4, and triangular retaining ring 5 are squeezed by the high medium pressure difference in the axial direction. Since the triangular retaining ring is made of polyetheretherketone (PEEK) or other highly wear-resistant materials, it can withstand extrusion under high medium pressure. At the same time, since the contact surface formed by the first inclined side 9 of the sealing ring 4 and the second inclined side 10 of the triangular retaining ring 5 is not perpendicular to the axis of the piston rod, under a large axial action, the sealing ring 4 and the triangular retaining ring 5 can induce a sliding action along the contact surface of the first inclined side 9 and the second inclined side 10, which provides a radial support to the sealing ring 4 away from the piston rod 2. This can prevent the sealing ring 4 from deforming too much and gripping the piston rod 2 under high medium pressure, and can also prevent the elastomer 3 from being squeezed by gaps caused by excessive deformation of the sealing ring 4. This can ensure the structural stability under high medium pressure.

[0056] When the sealing structure reciprocates, the first lip 7 and the second lip 8 of the sealing ring 4 are located on both sides of the sealing contact area between the sealing ring 4 and the piston rod 2. The first lip 7 faces the high-pressure side, and the angle between the first lip 7 and the axis of the piston rod 2 is an acute angle. The sealing ring 4 and the piston rod 2 form a convergent gap on the high-pressure side. When the piston rod 2 moves relative to the sealing ring 4 from the high-pressure side to the low-pressure side, a hydrodynamic oil film can be formed. The second lip 8 faces the low-pressure side, and the angle between the second lip 8 and the axis of the piston rod 2 is an acute angle. The sealing ring 4 and the piston rod 2 form a convergent gap on the low-pressure side. When the piston rod 2 moves relative to the sealing ring 4 from the low-pressure side to the high-pressure side, a hydrodynamic oil film can also be formed. Since the angle between the first lip 7 and the axis of the piston rod 2 is greater than the angle between the second lip 8 and the axis of the piston rod 2, according to fluid lubrication theory, the thickness of the hydrodynamic oil film formed when the piston rod 2 moves relative to the sealing ring 4 from the low-pressure side to the high-pressure side will be higher than the thickness of the hydrodynamic oil film formed when the piston rod 2 moves relative to the sealing ring 4 from the high-pressure side to the low-pressure side. This generates a net flow from the low-pressure side to the high-pressure side, which offsets the leakage of the medium from the high-pressure side to the low-pressure side, ensuring a low leakage during reciprocating motion.

[0057] The above-described embodiments are merely preferred embodiments of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be included within the scope of protection of the present invention.

Claims

1. A seal structure of a special triangular cross section, characterized by include: Housing bushing (1), piston rod (2), elastomer (3), sealing ring (4), triangular retaining ring (5), concave surface (6), first lip (7), second lip (8), first bevel (9), second bevel (10), cut (11); The piston rod (2) is fitted inside the housing bushing (1), and a sealing groove is provided on the inner side of the housing bushing (1); an elastic body (3), a sealing ring (4) and a triangular retaining ring (5) are arranged in sequence along the axial direction in the sealing groove; The elastic body (3) is a ring-shaped structure with a circular cross-section; The sealing ring (4) is a circular structure with an irregular cross-section. The cross-sectional structure of the sealing ring (4) has an inner concave surface (6), a first lip (7), a second lip (8), a first inclined side (9), and an auxiliary inclined side. The inner concave surface (6), the first lip (7), the second lip (8), the first inclined side (9), and the auxiliary inclined side are connected in sequence to form the irregular cross-section of the sealing ring (4). The inner concave surface (6) is in concave-convex fit with the elastic body (3). The triangular retaining ring (5) is a circular structure with an irregular cross section and has a cut (11); the cross section structure of the triangular retaining ring (5) has a second inclined side (10), and the second inclined side (10) is in contact with the first inclined side (9); During assembly and operation, the elastomer (3) is close to the high-pressure side, the triangular retaining ring (5) is close to the low-pressure side, and the sealing ring (4) is located between the elastomer (3) and the triangular retaining ring (5). The elastomer (3) is in contact with the housing bushing (1) and the sealing ring (4), but the elastomer (3) is not in direct contact with the piston rod (2); The sealing ring (4) is in direct contact with the piston rod (2). The first lip (7) and the second lip (8) are located on both sides of the contact area between the sealing ring (4) and the piston rod (2). The first lip (7) faces the high pressure side, and the second lip (8) faces the low pressure side. The angle between the first lip (7) and the axis of the piston rod (2) toward the high-pressure side is an acute angle, and the angle value is the first angle. The angle between the second lip (8) and the axis of the piston rod (2) toward the low-pressure side is an acute angle, and the angle value is the second angle. The first angle is greater than the second angle. The angle between the first hypotenuse (9) and the axis of the piston rod (2) facing the low-pressure side is an acute angle.

2. The profiled triangular cross-section seal structure of claim 1, wherein, The angle between the first hypotenuse (9) and the axis of the piston rod (2) facing the low-pressure side is greater than 45°.

3. The profiled triangular cross-section seal structure of claim 1, wherein, The angle between the second lip (8) and the axis of the piston rod (2) facing the low-pressure side is less than 30°.

4. The profiled triangular cross-section seal structure of claim 1, wherein, The thickness of the triangular retaining ring (5) at the end facing the bottom of the sealing groove is less than the thickness at the end facing the piston rod (2).

5. The profiled triangular cross-section seal structure of claim 1, wherein, The triangular retaining ring (5) is made of polyetheretherketone.

6. The profiled triangular cross-section seal structure of claim 1, wherein, The sealing ring (4) is made of polytetrafluoroethylene.

7. The profiled triangular cross-section seal structure of claim 1, wherein, The elastomer (3) is made of rubber.

8. The profiled triangular cross-section seal structure of claim 1, wherein, The sealing ring (4) is interference-fitted with the outer cylindrical surface of the piston rod (2).

9. The profiled triangular cross-section seal structure of claim 1, wherein, The elastomer (3) is interference-fitted with the bottom of the sealing groove of the housing bushing (1).

10. A hydraulic system characterized by, include: The hydraulic product adopts the irregular triangular cross-section sealing structure as described in any one of claims 1-9.

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