JPS6224662B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic seal device for a bearing portion having a relatively small sliding stroke.

Conventionally, a hydraulic seal mechanism in a bearing portion such as a piston rod portion of a hydraulic cylinder or a valve rod portion has been constructed as shown in FIG.

An annular groove 2 is formed in the bearing part 1, and a sealing member 3 is fitted into this annular groove 2 and comes into contact with the outer periphery of a rod 4 that slides in the axial direction. This prevents the water from leaking to the outside through transmission.

By the way, even if the sliding stroke of the rod 4 is small, if the reciprocating motion cycle is intense (for example, in the case of a hydraulic cylinder that vibrates at high frequency during the short stroke or the rod sliding part of a poppet type valve), the rod may be moved due to the angle of the bearing part 1, etc. Sliding scratches and abrasion are likely to occur on the surface of seal member 4, but under such usage conditions, seal member 3 may be damaged or interference may change, resulting in a marked deterioration of sealing performance. There were also problems such as low durability of the seal member 3.

In order to solve these problems, the present invention regulates the position of the bearing part and the seal member based on the relationship with the rod sliding stroke, and removes damaged or worn rod parts from the contact area with the seal member. The purpose of the present invention is to provide a hydraulic seal device with a

Embodiments of the present invention will be described below based on the drawings.

The embodiment shown in FIG. 2 is a case in which both sides of the bearing part are sealed together, and the bearing part 11 has an annular relief with a predetermined groove depth on the inner peripheral surface where it slides with the rod (shaft member) 12. A groove 13 is formed, and an annular groove 15 for holding a seal member 14 is formed in the center of the escape groove 13.

The width (axial length) of this relief groove 13 is determined based on the relationship with the sliding stroke of the rod 12. If the effective stroke of the rod is S, it extends from both sides of the seal member 14 to the end faces of the bearings 11A and 11B. The distance l is set so that l>S.

In this case, the rod areas that contact the bearings 11A and 11B do not reach the contact area with the sealing member 14, which may cause the rod 12 to move violently or be subjected to bending loads, etc. Even if the surface of the rod in contact with the bearing parts 11A, 11B is scratched or worn, it is possible to avoid damage to the sealing member 14 and changes in the tightening allowance due to this part. .

In other words, since there is no mechanical contact between the circumferential surface of the rod 12 at the left and right relief grooves 13A and 13B, the surface will not be damaged in these areas.

Therefore, if the width l of the left and right relief grooves 13A, 13B is made larger than the rod stroke S, the bearing part 1 will always reach the seal member 14.
Since the rod portions that are in contact with 1A and 11B do not come into contact with each other, the sealing member 14 comes into sliding contact only with the clean rod surfaces that are always kept in their initial state.

The embodiment shown in FIG. 3 is a case in which the seal member 14A seals only on one side. For example, assuming that the hydraulic oil pressure acts only from the left side in the figure, an inclined lip 17 is provided on the sliding surface with the rod 12. It is formed on the left end.

In this case, it is sufficient that the distance l from this lip 17 to the end face of the right bearing portion 11B is greater than the rod stroke S.

Further, in the embodiment shown in FIG. 4, a large diameter flange portion 18 is provided on a part of the rod 12, and at the same time, an annular groove 19 is provided adjacent to the bearing portion to regulate the operating stroke and to serve as the bearing portion 11'A. It was formed.

In this case, since the rod 12 makes sliding contact only with the right bearing portion 11B, the distance l from its end face to the lip 17 may be made larger than the stroke S.

Next, the embodiment shown in FIG. 5 is a case of a shaft side seal, in which a seal member 21 is attached to a piston portion 20, relief grooves 22A, 22B are formed on both sides of the seal member 21, and both ends of the seal member 21 are attached to the inner circumference of a cylinder 23. The bearing parts 24A and 24B are in contact with the bearing parts 24A and 24B.

Note that the operating stroke S of the piston portion 20 is
Since it is determined by the distance between the cylinder side walls 25A and 25B at both ends, the width l of the relief grooves 22A and 22B is made larger than the stroke S.

Even in this case, since the seal member 21 does not reach the inner circumferential surface of the cylinder 23 that is in constant contact with the bearing portions 24A, 24B, good sealing performance is always ensured.

As described above, according to the present invention, since the sliding contact area of the seal member is removed from the part that slides in contact with the bearing part and is susceptible to wear and damage, it is possible to always maintain good sealing performance and improve its durability. It has the effect of improving

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional device. 2 to 5 are cross-sectional views showing the first to fourth embodiments of the present invention, respectively. 11, 11A, 11B, 24A, 24B... Bearing part, 12... Rod, 13, 13A, 13B,
22A, 22B... Relief groove, 14, 14A, 21
... Seal member, 15 ... Annular groove, 17 ... Lip, 20 ... Piston part.

Claims (1)

[Claims] 1. In a hydraulic seal device in which an annular seal member is interposed on the sliding surface of a shaft member and a bearing member, an annular relief groove is formed on both sides of the seal member and does not touch the sliding part, and the width of this relief groove is A hydraulic seal device characterized in that the stroke is larger than the sliding stroke.