JP2002181010A - Seal ring of hydraulic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seal ring having reduced clearance when cooling hydraulic equipment and reduced warming-up operation. SOLUTION: In this seal ring 10 sealing between two relatively displacing members 102 and 110 of the hydraulic equipment 100, the seal ring 10 has a base part 12 fixed to one of two relatively displacing members and a seal part 14 facing the other member of two relatively displacing members, and the base part 12 and the seal part 14 are formed by different materials, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal ring for sealing between two relatively displaceable members of a hydraulic device.

[0002]

2. Description of the Related Art In a hydraulic device, for example, a hydraulic pump or a hydraulic cylinder, a gap or clearance (hereinafter simply referred to as a clearance) is provided between two relatively displaceable members in the hydraulic device, for example, a piston and a cylinder. Is provided. Therefore, a seal ring is disposed between the piston and the cylinder in order to prevent the hydraulic oil from leaking from the clearance. And the seal ring
In order to prevent seizure on the piston, a material softer than the material of the piston, for example, a copper alloy is used.

[0003]

In a hydraulic device, the internal temperature increases during use and the clearance decreases, so that the size of the seal ring is determined in consideration of the reduction in the clearance. Therefore, when the hydraulic device is cold, the clearance is relatively large. As described above, since the seal ring is made of a material softer than the material of the piston, for example, a copper alloy, the coefficient of linear thermal expansion of the seal ring is larger than the coefficient of linear thermal expansion of the piston. . Therefore, the clearance in the cold state must be increased, and therefore, there is a problem that the warm-up operation of the conventional hydraulic equipment must be lengthened.

An object of the present invention is to solve such problems of the prior art, and it is an object of the present invention to provide a seal ring in which the clearance during cold operation is reduced and the warm-up operation of hydraulic equipment is reduced. .

[0005]

According to the present invention, there is provided a seal ring for sealing between two relatively displaceable members of a hydraulic device, wherein the seal ring is provided with the relatively displaceable two member. A base portion fixed to one of the two members, and a seal portion facing the other of the two relatively displaceable members, wherein the base portion and the seal portion are formed of different materials. The gist of the present invention is a seal ring.

[0006] With this configuration, it is possible to preferably select the linear thermal expansion coefficient of the entire seal ring. The hydraulic device, for example, a cylindrical cylinder housing,
A hydraulic cylinder comprising a piston disposed reciprocally in the axial direction within the cylinder housing, in which case the seal ring may be an annular base;
A sealing portion provided along the inner peripheral surface of the base portion, and formed of an annular member having a central opening defined by the sealing portion, and the base portion is formed in the cylinder housing. Can be fixed to the inner wall of the cylinder housing, and the piston can be slidably received in the central opening in the axial direction. In this case, the base portion can be formed from a material having a linear thermal expansion coefficient substantially equal to that of the piston.

[0007] The seal portion may be formed of a material that is more flexible than the base portion, for example, a copper alloy. The seal portion may be fitted to the base portion or aluminum bronze may be padded on the base portion. It can be formed by welding.

[0008]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. Referring to FIG. 2, a hydraulic cylinder 100 is illustrated as a hydraulic device to which the sealing member according to the present invention is applied. The hydraulic cylinder 100
Hollow cylinder housing 10 forming a cylinder
2. The piston 110 is provided so as to be able to reciprocate relative to the cylinder housing 102 in the direction of the central axis O within the internal space 104 of the cylinder housing 102. The piston 110 includes shaft portions 114 and 116 extending in the direction of the central axis O, and shaft portions 114 and 116.
And a piston portion 112 provided in the middle between the two.
An oil ring (not shown) is attached to the piston portion 112. The bearing 10 that slidably supports the shaft portions 114 and 116 is provided in the internal space of the cylinder housing 102.
6, 108 are provided. One shaft 116 of the piston 110 penetrates an opening 102 a formed at the center of one end of the cylinder housing 102 and protrudes outside the cylinder housing 102. A driven member (not shown) is connected to a shaft portion 116 protruding outside the cylinder housing 102.

In this embodiment, the cylinder housing 10
A pair of seal rings 10 are disposed inside the bearings 106 and 108 in the second internal space 104, and an extension-side pressure chamber 118 and a contraction-side pressure chamber 120 are provided between the piston 112 and each of the seal rings 10. It is formed. The cylinder housing 102 includes hydraulic ports 102b, 1b, 1c, which communicate with the expansion-side pressure chamber 118 and the contraction-side pressure chamber 120, respectively.
The hydraulic ports 102b and 102c are connected to a hydraulic pressure source (not shown) provided outside the hydraulic cylinder 100.

Referring to FIG. 1, a seal ring 10 comprises
An annular member having a center opening 16 for passing the shaft portions 114 and 116 of the piston 110, a ring-shaped base member 12 on the outside in the radial direction, and a seal portion formed along the inner peripheral surface of the base portion 12. 14. In the seal ring 10, the base portion 12 is fixed to the inner wall of the cylinder housing 102 in the cylinder housing 102, and the piston 110, in the present embodiment, the shaft portion 116 of the piston 110 slides in the direction of the center axis O in the central opening portion 16. It is arranged to be freely received. The base portion 12 is formed from a material having the same linear thermal expansion coefficient as the piston 110, and the seal portion 14 is formed from a flexible material, for example, a copper alloy or an aluminum alloy. In this embodiment, the piston 110 is formed from a steel material,
2 is formed from the same steel material as the piston 110,
The seal portion 14 is formed by overlay welding of a copper alloy, for example, aluminum bronze along the inner peripheral surface of the base portion 12.

Hereinafter, the operation of the present embodiment will be described. When hydraulic pressure is applied to the hydraulic pressure port 102b communicating with the expansion-side pressure chamber 118, the piston 110 moves rightward in FIG.
2c. Conversely, when hydraulic pressure is applied to the hydraulic port 102c communicating with the contraction-side pressure chamber 120, the piston 110 moves to the left in FIG. 2, and the hydraulic oil in the extension-side pressure chamber 118 is discharged from the hydraulic port 102b. You. At this time, the internal space 10 of the cylinder housing 102 is
The seal ring 10 disposed in the inside 4 prevents leakage of hydraulic oil from the expansion-side pressure chamber 118 and the contraction-side pressure chamber 120.

A predetermined clearance is provided between the central opening 16 of the seal ring 10 and the arms 114 and 116 of the piston 110 in order to prevent direct contact between the two. In the prior art, the seal ring is formed only of a flexible material such as a copper alloy, and a flexible material such as a copper alloy used for sealing such a clearance is more generally used than the steel material forming the piston 110. It has a large linear thermal expansion coefficient. For this reason, the conventional seal ring is more thermally deformed than the piston in response to a temperature change of the hydraulic cylinder 100, so that the clearance at the time of cold has to be set large. On the other hand, the seal ring 10 according to the present embodiment is a material having the same linear thermal expansion coefficient as the piston 110, typically the same material as the piston 110, specifically, the inner peripheral surface of the base portion 12 made of a steel material. Since the seal portion 14 made of a flexible material is provided, the coefficient of linear thermal expansion is reduced in each step. Therefore, it is possible to reduce the clearance in the cold state.

[Brief description of the drawings]

FIG. 1 is a seal ring according to a preferred embodiment of the present invention, wherein (a) is a plan view and (b) is a cross-sectional view.

FIG. 2 is a sectional view of a hydraulic cylinder as an example of a hydraulic device to which the seal ring of the present invention is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Seal ring 12 ... Base part 14 ... Seal part 100 ... Hydraulic cylinder 102 ... Cylinder housing 110 ... Piston

Claims (7)

[Claims] 1. A seal ring for sealing between two relatively displaceable members of a hydraulic device, wherein the seal ring is fixed to one of the two relatively displaceable members; And a seal portion facing the other of the two members that are displaced in a horizontal direction,
A seal ring, wherein the base portion and the seal portion are formed of different materials. 2. The hydraulic device according to claim 1, wherein the hydraulic device is a hydraulic cylinder including a cylindrical cylinder housing, and a piston disposed in the cylinder housing so as to reciprocate in an axial direction. And a seal member provided along the inner peripheral surface of the base portion, and is formed of an annular member having a central opening defined by the seal portion. The seal ring according to claim 1, wherein the base portion is fixed to the inner wall of the cylinder housing in the cylinder housing, and the piston is slidably received in the central opening in the axial direction. 3. The seal ring according to claim 2, wherein said base portion is formed of a material having a linear thermal expansion coefficient substantially equal to that of said piston. 4. The device according to claim 1, wherein the seal portion is formed of a material that is more flexible than the base portion.
The seal ring according to the item. 5. The seal according to claim 1, wherein said seal portion is made of a copper alloy.
5. The seal ring according to any one of items 1 to 4. 6. The seal ring according to claim 1, wherein said seal portion is fitted to said base portion. 7. The seal ring according to claim 1, wherein the seal portion is formed by overlay welding aluminum bronze to the base portion.