JP2725948B2 - Seal ring - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal ring such as a piston ring having a joint at both ends.

[0002]

2. Description of the Related Art Conventionally, a seal ring having a structure in which the abutment portions at both ends are overlapped is configured as shown in FIG. That is, this configuration is obtained by reducing the thickness of both ends of the seal ring and polymerizing them.

[0003]

However, in the above seal ring, the abutment portion has insufficient adhesion. For this reason, when internal pressure is given to a cylinder, there are many leaks from between a mouth parts. In order to reduce the leakage 29, the dimensional accuracy, flatness, parallelism,
There is a problem that the surface roughness needs to be improved, and the production cost increases.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a seal ring capable of reducing leakage from the joint by subjecting the joint of the seal ring to simple processing.

[0005]

In order to achieve the above object, according to a first aspect of the present invention, in a seal ring in which the abutments at both ends are overlapped, the abutment has a surface where the abutments come into contact with each other.
The gist of the invention is that at least one groove is formed on the back side of the seal ring so as to cross the inner peripheral side and the outer peripheral side of the seal ring .

[0006] In the second invention, the groove is formed at the joint portion.
The gist is that a plurality of grooves are provided side by side from the base end to the tip end, and the grooves are formed deeper toward the end of the abutment.

[0007]

According to the above construction, in the first aspect of the present invention, from the inner peripheral side of the seal ring to the outer peripheral side with respect to the surface where the abutting portions contact each other.
Since a local force can be applied over the entire surface, the adhesion is improved.

[0008] In the second aspect, the flexibility of the abutment portion increases as approaching the tip of the abutment portion. On the other hand, the leak pressure acting on the joint becomes smaller as approaching the tip of the joint, but the amount of deformation due to the internal pressure of the cylinder becomes greater toward the tip of the joint.
Therefore, the sealing performance of the joint portion works uniformly.

[0009]

【Example】

(First Embodiment) A first embodiment in which the present invention is embodied in a seal ring of a hydraulic cylinder will be described below with reference to FIGS.

As shown in FIG. 3, the hydraulic cylinder 1 comprises a cylinder tube 2 and rod covers 3 and head covers 4 fixed to both ends thereof. The supply / discharge ports 5 and 6 are formed in the rod cover 3 and the head cover 4, respectively, and they communicate with the cylinder chambers R1 and R2 of the cylinder tube 2. The insertion hole 7 is bored through the center of the rod cover 3. The piston head 9 of the piston 8 has an annular groove 10 on its circumference, and is movable into the tube 2 together with the rubber O-ring 11 and the synthetic resin seal ring 12 housed in the annular groove 10. Has been inserted. The piston rod 13 penetrates the insertion hole 7 via a rubber O-ring 15 and a synthetic resin seal ring 16 housed in the annular groove 14 of the rod cover 3. O-rings 11 and 15 and seal ring 1 provided in piston head 9 and insertion hole 7
2 and 16 are arranged so that the seal rings 12 and 16 are in contact with the sliding surfaces. That is,
The O-rings 11 and 15 urge the seal rings 12 and 16 in the radial direction or the radial direction by their own elasticity. Therefore, the seal rings 12, 16 are in contact with the inner peripheral surface of the tube 2 or the outer peripheral surface of the piston rod 13 with a spring force due to its own elasticity.

The seal rings 12 and 16 are made of a synthetic resin material having a small coefficient of friction, for example, Teflon or the like.
As shown in the figure, the abutment part 1 is formed as a whole and is polymerized at both ends.
7. The plurality of grooves 18 are formed on the outer surface of the abutment portion 17 so as to penetrate between the inner peripheral surface and the outer peripheral surface.

The operation of the seal ring configured as described above will be described. When the fluid is supplied from one supply / discharge port 5 of the fluid pressure cylinder 1 and discharged from the other supply / discharge port 6, the piston 8 is moved by the fluid pressure. At this time, for example, one side of the seal ring 12 on the piston head 9 side is in a pressurized state, and the other side is in a non-pressurized state.

As shown in FIG. 2, a force (a) generated from the pressure distribution due to leakage acts on the inner surface of the abutment portion 17,
The force (b) generated from the pressing force acts on the outer surface of the abutment portion 17. The force (a) generated from the pressure distribution due to leakage is large at the front end side of the joint 17 and the force is
Working in the direction of opening 7. On the other hand, the force (b) due to the pressing force acts uniformly on one side surface of the abutment portion 17 in a direction in which the abutment portion 17 is brought into close contact. These two forces (a), (b)
(C) actually acts on the abutment portion 17, and the resultant force (c) acts in a direction in which the abutment portion 17 is brought into close contact with the abutment portion 17, and the size is smaller on the distal end side.

On the other hand, a groove 18 formed on the side face of the joint 17
Thereby, the flexibility of the joint portion 17 is increased. In addition, the groove 18 is formed deeper as it approaches the tip of the abutment 17, and as a result, the flexibility increases as it approaches the tip.

Therefore, while the resultant force (c) applied to the abutment portion 17 decreases toward the distal end, the flexibility increases toward the distal end and the amount of deformation due to the force (a) increases. It becomes uniform over the whole, and leakage can be reduced.

In addition, since the tip of the abutment portion 17 is not recessed and retains its original thickness, it does not deform so that the tip is turned up due to leakage pressure, and can contribute to the uniform sealing described above and increase strength. Can be kept.

Further, the groove 18 is provided with the seal rings 12 and 16.
It is formed at the same time as molding, or is formed by simple processing that is only cut after molding

[0018]

Next, another embodiment of the present invention will be described with reference to FIGS. In the following description, the same components as those of the above-described embodiment will be denoted by the same reference numerals in the drawings, and description thereof will be omitted.

In the second embodiment shown in FIG. 4, a plurality of grooves 20 are formed on the outer surface of the abutment portion 19 as in the previous embodiment, but the depth of each groove 20 is constant. Further, in the third embodiment, as shown in FIG. 5, each groove 22 is formed wide at the abutment portion 21, and in this embodiment, there are two grooves 22. The elasticity is almost the same as that of the second embodiment, but the number of the grooves 22 is small, so that the formation is easy and the cost can be reduced.

Subsequently, as shown in FIG. 6, in the fourth embodiment, one groove 24 is formed in the outer surface of the abutment portion 23, and the bottom surface is formed deeper toward the tip. As shown in FIG. 7, the fifth embodiment has a structure in which one of the abutment portions 25 is formed in the convex portion 26 and the other is formed in the concave portion 27 and fitted together. A plurality of grooves 28 are formed on both side surfaces of the concave portion 27. In this configuration, since the groove 28 formed in the concave portion 27 and the convex portion 26 and the concave portion 27 are overlapped in a sandwich shape, the sealing performance is further improved.

The present invention is not limited to the structure of the above-described embodiment. For example, the seal ring may be used alone for a fluid pressure cylinder without being overlapped with an O-ring, or a metal seal may be used as the seal ring. The configuration of each unit may be arbitrarily changed and embodied without departing from the spirit of the present invention, such as by using a device.

[0022]

According to the first aspect of the present invention, the inner surface of the seal ring extends from the inner peripheral side to the outer peripheral side with respect to the surface where the abutment portions contact each other.
It is possible to provide a localized force I, improved adhesion, dimensional accuracy of the portion overlapping abutment joint, flatness, parallelism, without improving the surface roughness, from the abutment portion of the seal ring There is an effect that leakage can be reduced by inexpensive processing.

According to the second invention, an effect that a uniform one sealing property can be ensured.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of a seal ring embodying the present invention.

FIG. 2 is a cross-sectional view of a main part showing an abutment portion of the first embodiment of the seal ring.

FIG. 3 is a sectional view of a hydraulic cylinder equipped with a seal ring of the present invention.

FIG. 4 is a cross-sectional view of a main part showing an abutment portion of a second embodiment of the seal ring.

FIG. 5 is a cross-sectional view of a principal part showing a joint portion of a third embodiment of the seal ring.

FIG. 6 is a cross-sectional view of a main part showing an abutment portion of a fourth embodiment of the seal ring.

FIG. 7 is a cross-sectional view of a principal part showing an abutment portion of a fifth embodiment of the seal ring.

FIG. 8 is a cross-sectional view of a main part showing a joint portion of a conventional example of a seal ring.

[Explanation of symbols]

 12, 16 seal rings, 17 joints, 18 grooves.

Claims (2)

(57) [Claims] 1. A seal ring in which an abutment portion at both ends is superimposed, wherein the abutment portion has a seal on a back side of a surface where the abutment portions are in contact with each other.
Sheet Ruringu forming at least one groove transverse to the inner and outer peripheries of Luling. 2. The method according to claim 1, wherein the groove is formed from a base end to a tip end of the abutment.
2. The seal ring according to claim 1, wherein a plurality of grooves are arranged side by side, and the grooves are formed so as to be deeper toward the tip of the abutment portion.