Gas spring oil seal
By setting a specific height on the lip of the gas spring oil seal and forming multiple circumferential protrusions on the inner peripheral surface, the problem of insufficient sealing performance under high pressure conditions in the prior art is solved, and a more efficient sealing effect is achieved.
Patent Information
- Application Number
- CN202421582094.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-05
- Publication Date
- 2025-04-29
- Estimated Expiration
- 2034-07-05
AI Technical Summary
The existing gas spring oil seals have insufficient sealing performance under high pressure conditions, making it difficult to meet the sealing requirements for high pressure use.
A new gas spring oil seal was designed, with the height (h) of the lips being set to a thickness (T) of 1.2 to 1.5 times, and multiple circumferential protrusions were formed on the inner peripheral surface to improve the rigidity and sealing performance of the lips.
By improving the rigidity and sealing performance of the lips, the newly designed gas spring oil seal can seal gas or oil more effectively under high pressure conditions, significantly improving the sealing performance.
Smart Images
Figure CN222811138U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a gas spring oil seal. Background Art
[0002] For example, a gas spring has a piston rod that holds a reciprocating piston and a cylinder that accommodates the piston rod. In order to seal the annular sealed space between the piston rod and the cylinder, an oil seal is used. The oil seal, for example, has an annular reinforcement ring and an elastic body formed integrally with the reinforcement ring. The elastic body has an annular lip portion arranged on the inner circumference of the reinforcement ring and an annular outer circumference portion arranged on the outer circumference of the reinforcement ring. Utility Model Content
[0003] Issues to be solved by utility models
[0004] Such an oil seal is pressed into the inner peripheral surface of the cylinder body at the outer peripheral portion, and on the other hand, the lip portion slides on the outer peripheral surface of the piston rod that reciprocates along the axial direction. In this way, gas or oil is sealed in the annular sealing space between the piston rod and the cylinder body. Such an oil seal is required to be used under high-pressure conditions, but under such high-pressure conditions, the sealing performance needs to be further improved.
[0005] The utility model is completed in view of the above-mentioned problems, and its purpose is to provide a gas spring oil seal capable of further improving the sealing performance.
[0006] Means for solving problems
[0007] In order to achieve the above-mentioned purpose, the gas spring oil seal involved in the utility model includes: a reinforcement ring, which is annular around an axis; and an elastomeric portion, which is formed integrally with the reinforcement ring and is annular around the axis; the elastomeric portion has an annular lip portion arranged on the inner peripheral side of the reinforcement ring, and if the thickness between the inner peripheral surface and the outer peripheral surface of the lip portion specified around the axis is set to T, and the height of the lip portion in the axial direction along the axis is set to h, then 1.2T≤h≤1.5T.
[0008] In the gas spring oil seal of the present invention, the lip portion extends from the inner peripheral end of the reinforcement ring toward one side in the axial direction and toward the inner peripheral side in the radial direction orthogonal to the axis.
[0009] In the gas spring oil seal of the present invention, the lip portion defines a first surface facing one side in the axial direction and a second surface facing the other side in the axial direction, and the inner peripheral surface corresponds to the second surface.
[0010] In the gas spring oil seal of the present invention, the lip portion has a plurality of circumferential protrusions formed on the second surface and extending around the axis.
[0011] Utility Model Effect
[0012] According to the utility model, a gas spring oil seal capable of further improving the sealing performance can be provided. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Figure 1 This is a cross-sectional view schematically showing the structure of a gas spring oil seal 1 according to one embodiment of the present invention.
[0014] Figure 2 This is an enlarged end view of the gas spring oil seal 1 schematically showing the structure of the sealing device 1 .
[0015] Figure 3 It is a partial end view schematically showing the structure of a sealing structure 2 of a specific example.
[0016] Figure 4 It is an enlarged cross-sectional view of a sealing device 1A according to another embodiment of the present invention. DETAILED DESCRIPTION
[0017] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Figure 1 This is a cross-sectional view schematically showing the structure of a sealing device (ie, oil seal) 1 according to one embodiment of the present invention. Figure 2 1 is an enlarged end view of the sealing device 1 schematically showing the structure of the sealing device 1. Figure 1 and Figure 2 They are cross-sectional views or end views of a cross section including the axis x. The sealing device 1 is applied to, for example, a gas spring. The gas spring has a reciprocating piston rod and a cylinder body accommodating the piston rod. The oil seal 1 is an oil seal for sealing the annular space between the piston rod and the cylinder body. The oil seal 1 can be applied to, for example, industrial machinery, automobiles, aerospace, medical equipment, metallurgical industry, energy and other fields.
[0018] like Figure 1 and Figure 2 As shown, for the sake of convenience, one side in the direction of the axis x (hereinafter referred to as the "axial direction") is defined as the first side S1, and the other side in the axial direction is defined as the second side S2. Specifically, the first side S1 is the gas side where there is a sealed object such as gas, and the second side S2 is the atmosphere side where there is no sealed object such as gas. In addition, the direction away from the axis x in the direction orthogonal to the axis x (hereinafter referred to as the "radial direction") is defined as the outer peripheral side SO, and the direction close to the axis x is defined as the inner peripheral side SI. In addition, the direction around the axis x is defined as the circumferential direction.
[0019] The oil seal 1 includes an elastomer portion 20, which includes an annular reinforcement ring 10 centered on the axis x and an annular elastomer centered on the axis x. The reinforcement ring 10 is formed of, for example, a metal material. The metal material includes, for example, stainless steel and SPCC (cold rolled steel). On the other hand, the elastomer of the elastomer portion 20 includes, for example, a synthetic rubber such as nitrile rubber (NBR), hydrogenated nitrile rubber (H-NBR), acrylic rubber (ACM), and fluororubber (FKM).
[0020] The elastomer portion 20 is formed integrally with the reinforcement ring 10. The reinforcement ring 10 is manufactured, for example, by stamping or forging. The elastomer portion 20 is formed by crosslinking (vulcanization) molding using a molding die. During the crosslinking molding, the reinforcement ring 10 is pre-arranged in the molding die. In this state, by heating and pressurizing the elastomer injected into the molding die, the elastomer is crosslinked and bonded to the reinforcement ring 10. In this way, the elastomer portion 20 is formed integrally with the reinforcement ring 10.
[0021] In this example, the reinforcement ring 10 is formed into a flat ring around the axis x. The reinforcement ring 10 extends in a ring shape along a virtual plane orthogonal to the axis x. The reinforcement ring 10 defines a first surface 11 and a second surface 12 facing each other in the axial direction and an outer peripheral surface 13 and an inner peripheral surface 14 facing each other in the radial direction. The first surface 11 is an annular surface facing the first side S1, and the second surface 12 is an annular surface facing the second side S2. In addition, the outer peripheral surface 13 is a cylindrical surface facing the outer peripheral side SO, and the inner peripheral surface 14 is a cylindrical surface facing the inner peripheral side SI.
[0022] The elastic body portion 20 is formed integrally with the reinforcement ring 10 in a manner covering at least a portion of the reinforcement ring 10. The elastic body portion 20 has a lip portion 21, an outer peripheral portion 22, and an axial direction cover 23. The lip portion 21, the outer peripheral portion 22, and the axial direction cover 23 are formed integrally with each other. The lip portion 21 is arranged on the inner peripheral side SI of the reinforcement ring 10, and on the other hand, the outer peripheral portion 22 is arranged on the outer peripheral side SO of the reinforcement ring 10. The axial direction cover 23 covers the first surface 11 of the reinforcement ring 10.
[0023] The lip portion 21 is a portion extending from the inner peripheral end 15 defined by the inner peripheral side SI of the reinforcement ring 10 toward the first side S1 and the inner peripheral side SI. The inner peripheral end 15 is a portion of the reinforcement ring 10 close to the inner peripheral side SI including the inner peripheral surface 14. On the other hand, the outer peripheral portion 22 is a portion extending from the outer peripheral end 16 defined by the outer peripheral side SO of the reinforcement ring 10 toward the first side S1 and the outer peripheral side SO. The outer peripheral end 16 is a portion of the reinforcement ring 10 close to the outer peripheral side SO including the outer peripheral surface 13. The axial direction cover 23 is, for example, an annular portion that connects the lip portion 21 and the outer peripheral portion 22 to each other. In this example, the thickness of the axial direction cover 23 defined in the axial direction is constant in the radial direction.
[0024] The lip portion 21 covers the entire inner circumferential surface 14 of the reinforcement ring 10 and a portion of the first surface 11 at the inner circumferential end 15 of the reinforcement ring 10. The lip portion 21 has a wedge-shaped lip front end portion 24 that protrudes toward the inner circumferential side SI. The lip front end portion 24 has a lip front end 25. The lip front end 25 is a portion located on the innermost circumferential side SI that describes a circle centered on the axis x in a cross section perpendicular to the axis x. When the oil seal 1 is assembled to an applicable object, the vicinity of the lip front end 25 is in close contact with the outer circumferential surface of the piston rod in a slidable manner.
[0025] The lip tip portion 24 defines an annular first surface 26 facing the first side S1 and an annular second surface 27 facing the second side S2, which are connected via the lip tip 25, on its inner circumferential side S1. That is, the lip tip portion 24 is a portion that defines the first surface 26 and the second surface 27, including the lip tip 25. The first surface 26 is a conical surface that expands in diameter toward the first side S1. The second surface 27 is a conical surface that expands in diameter toward the second side S2. The lip tip 25 is formed at the portion where the first surface 26 and the second surface 27 intersect.
[0026] The lip portion 21 defines an annular inner peripheral surface (ie, second surface) 27 around the axis x on the inner peripheral side SI, and defines an annular outer peripheral surface 28 around the axis x on the outer peripheral side SO. Figure 2 As shown, the thickness T of the lip portion 21 is defined between the inner peripheral surface 27 and the outer peripheral surface 28. The thickness T is defined in a direction orthogonal to a truncated cone surface P centered on the axis x and defined at an intermediate position between the inner peripheral surface 27 and the outer peripheral surface 28 defined substantially in parallel.
[0027] On the other hand, in the lip portion 21, a height h is specified along the axial direction. The height h is consistent with the height from the end face 29 of the second side S2 of the lip portion 21 to the end face 30 of the first side S1 of the lip portion 21. In this example, the end face 29 and the end face 30 are specified to be substantially parallel to each other. That is, the end face 29 and the end face 30 are respectively specified along a virtual plane orthogonal to the axis x. In addition, the end face 29 is consistent with the second surface 12 of the reinforcement ring 10. In the oil seal 1, the height h of the lip portion 21 is set to: 1.2T≤h≤1.5T.
[0028] The outer peripheral portion 22 has an inner peripheral surface 31 and an outer peripheral surface 32. The inner peripheral surface 31 is an annular surface facing the inner peripheral side SI. The outer peripheral surface 32 is an annular surface facing the outer peripheral side SO. The inner peripheral surface 31 and the outer peripheral surface 32 are both tapered surfaces that expand in diameter toward the first side S1 in the axial direction. The inner peripheral surface 31 and the outer peripheral surface 32 are connected to each other through an annular end surface 33 extending along a virtual plane orthogonal to the axis x. The end surface 33 is a surface facing the first side S1. The outer peripheral portion 22 covers the outer peripheral surface 13 of the reinforcement ring 10.
[0029] In the state before the oil seal 1 is assembled to the application object, the diameter of the outer peripheral surface 32 of the outer peripheral portion 22 is set to be larger than the diameter of the inner peripheral surface of the cylinder. When the oil seal 1 is assembled to the application object, if it is pressed into the inner peripheral surface of the cylinder, the outer peripheral portion 22 is compressed in the radial direction between the inner peripheral surface of the cylinder and the outer peripheral surface 13 of the reinforcement ring 10. When being compressed in the radial direction, a force toward the outer peripheral side SO, that is, a fitting force, is set to be generated with a predetermined magnitude.
[0030] Next, a seal structure 2 in which the oil seal 1 according to one embodiment of the present invention is incorporated will be described. Figure 3 It is a partial end view schematically showing the structure of a sealing structure 2 of a specific example.
[0031] Figure 3 : is a partial end view of the sealing structure 2 in a cross section along the axis x. The sealing structure 2 includes: a cylinder 3; a piston rod 4, which holds a piston (not shown) inserted into the cylinder 3; and an oil seal 1, which seals a gap G formed between an inner peripheral surface 3a of the cylinder 3 and an outer peripheral surface 4a of the piston rod 4. The cylinder 3 and the piston rod 4 are, for example, a cylinder and a piston rod of a gas spring, respectively.
[0032] The cylinder body 3 defines, for example, a cylindrical space extending along the axis x. That is, the inner circumferential surface 3a of the cylinder body 3 is a cylindrical surface with the axis x as the center axis. On the other hand, the piston rod 4 is, for example, a cylindrical piston rod extending along the axis x. The outer circumferential surface 4a of the piston rod 4 is a cylindrical surface with the axis x as the center axis. The cylinder body 3 and the piston rod 4 are defined as being coaxial. Between the inner circumferential surface 3a of the cylinder body 3 and the outer circumferential surface 4a of the piston rod 4, a gap G extends in an annular shape. The piston rod 4 can reciprocate in the cylinder body 3 along the axial direction.
[0033] The oil seal 1 is pressed into the gap G. Specifically, the outer peripheral portion 22 of the elastomer portion 20 is pressed into the inner peripheral surface 3a of the cylinder body 3. The outer peripheral portion 22 is pressed in close contact with the inner peripheral surface 3a by elastic deformation. The reinforcement ring 10 maintains the fitting force generated by the pressing. On the other hand, the lip portion 21 is in contact with the outer peripheral surface 4a of the piston rod 4 near the lip front end 25. The lip front end portion 24 is in close contact with the outer peripheral surface 4a by elastic deformation. It should be noted that a lubricating oil such as grease is applied between the outer peripheral surface 4a of the piston rod 4 and the lip front end portion 24 including the lip front end 25 (not shown).
[0034] In the sealing structure 2 as described above, when the piston rod 4 reciprocates along the axis x, the lip 21 slides on the outer peripheral surface 4a of the piston rod 4 along the axial direction, so that the oil seal 1 seals the gas and the atmosphere. At the first side S1 closer to the gas side than the oil seal 1, the pressure of the gas acts in a manner to increase the pressure of the lip 21 relative to the outer peripheral surface 4a of the piston rod 4. In this way, in the lip 21, the vicinity of the lip front end 25 is in close contact with the outer peripheral surface 4a of the piston rod 4. The lubricating oil suppresses the friction between the vicinity of the lip front end 25 and the outer peripheral surface 4a of the piston rod 4.
[0035] In the oil seal 1, the height h of the lip 21 is set to 1.2T≤h≤1.5T, and the height h of the lip 21 is set to be slightly larger than its thickness T. Thus, by setting the height h to be substantially the same as the thickness T, the rigidity of the lip 21 can be increased. As a result, when the piston rod 4 reciprocates along the axis x, the lip 21 can be restrained from expanding and contracting in the axial direction due to friction with the outer peripheral surface 4a. The lip 21 can further improve the sealing performance.
[0036] Figure 4 This is an enlarged cross-sectional view of an oil seal 1A according to another embodiment of the present invention. In the oil seal 1A, a plurality of (three in this example) circumferential protrusions 34 extending circumferentially around the axis x are formed on the inner circumferential surface 27 of the lip portion 21. In this example, the plurality of circumferential protrusions 34 extend parallel to each other. The circumferential protrusions 34 are formed in a ring shape extending uninterruptedly around the axis x. In this example, a groove 35 extending circumferentially is formed between the circumferential protrusions 34, 34 adjacent in the axial direction. In the cross section including the axis x, each circumferential protrusion 34 has, for example, a triangular shape whose front end tapers as it moves toward the inner circumferential side SI.
[0037] In the oil seal 1A, a plurality of circumferential protrusions 34 are formed on the inner circumferential surface 27 of the lip portion 21. According to such a structure, an oil reservoir for holding lubricating oil such as grease can be formed in the groove 35 between the circumferential protrusions 34 and 34 adjacent in the axial direction. When the inner circumferential surface 27 of the lip portion 21 slides on the outer circumferential surface 4a of the piston rod 4, it is possible to promote the formation of an oil film on the inner circumferential surface 27 of the lip portion 21. In addition, the contact area between the inner circumferential surface 27 and the outer circumferential surface 4a of the piston rod 4 is reduced by the plurality of circumferential protrusions 34. As a result, the friction between the lip portion 21 and the piston rod 4 is reduced.
[0038] The present invention has been described above by the above-mentioned embodiments, but the technical scope of the present invention is not limited to the scope described in the above-mentioned embodiments. It is obvious to those skilled in the art that various changes or improvements can be made to the above-mentioned embodiments. According to the description of the claims, the method to which such changes or improvements are made is also included in the technical scope of the present invention.
[0039] The above-described embodiments are intended to facilitate understanding of the present invention and are not intended to limit the present invention. In addition, the above-described embodiments do not limit the objects of use of this solution, and this solution can include all solutions as its objects of use. The various components and their configurations, materials, conditions, shapes, and dimensions included in the above-described embodiments are not limited to the illustrated contents and can be appropriately changed. For example, the present invention includes differences generated in the implementation of manufacturing tolerances, etc. In addition, within the scope of technical non-contradiction, the components shown in different embodiments can be partially replaced or combined with each other. In addition, each structure can be appropriately and selectively combined to achieve at least a part of the above-mentioned topics and effects.
[0040] Description of reference numerals:
[0041] 1. 1A oil seal
[0042] 2 Sealing structure
[0043] 3 cylinder block
[0044] 3a Inner Surface
[0045] 4 piston rod
[0046] 4a Outer surface
[0047] 10Reinforcement ring
[0048] 11 Side 1
[0049] 12 Side 2
[0050] 13 Outer Surface
[0051] 14 Inner Surface
[0052] 15 inner peripheral end
[0053] 16 Peripheral end
[0054] 20 Elastomer
[0055] 21 Lips
[0056] 22 Peripheral part
[0057] 23 axis direction cover
[0058] 24 Lip front end
[0059] 25 Lip front end
[0060] 26 Side 1
[0061] 27 Second side (inner circumference)
[0062] 28 Outer Surface
[0063] 29 end face
[0064] 30 end face
[0065] 31 Inner Surface
[0066] 32 Outer Surface
[0067] 33 end face
[0068] 34 Circumferential protrusion
[0069] 35 slots
[0070] S1 first side
[0071] S2 Second side
[0072] SI inner side
[0073] SO outer side
[0074] G Clearance
[0075] P cone table
[0076] x-axis
Claims
1. A gas spring oil seal, characterized in that: include: a reinforcing ring, annular about the axis; and an elastic body portion, formed integrally with the reinforcement ring and in a ring shape around the axis; The elastic body portion has an annular lip portion arranged on the inner circumference side of the reinforcement ring. When T is the thickness between the inner peripheral surface and the outer peripheral surface of the lip portion defined around the axis, and h is the height of the lip portion in the axial direction along the axis, 1.2T≤h≤1.5T.
2. The gas spring oil seal according to claim 1, characterized in that: The lip portion extends from an inner peripheral end of the reinforcement ring toward one side in the axial direction and toward an inner peripheral side in a radial direction orthogonal to the axis.
3. The gas spring oil seal according to claim 2, characterized in that: The lip portion defines a first surface and a second surface, the first surface faces one side in the axial direction, the second surface faces the other side in the axial direction, and the inner peripheral surface corresponds to the second surface.
4. The gas spring oil seal according to claim 3, characterized in that: The lip portion has a plurality of circumferential protrusions formed on the second surface and extending around the axis.