JPS6224865Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sealing device that is fitted between first and second members that fit together in a fluid pressure device or the like to prevent leakage of pressure fluid.

As shown in FIG. 1, a conventional sealing device of this type has an annular groove 3 formed on the outer periphery of a second member 2 that fits into a first member 1, and a seal ring 4 mounted in this annular groove 3. When the seal ring 4 is fitted into the first member 1, pressure fluid is introduced into the radial gap 5 between the seal ring 4 and the annular groove 3 to stretch the seal ring 4 around the outer periphery. It is crimped onto the inner peripheral surface of the matching hole for more effective sealing.

However, in such a conventional device, since there is a radial gap 5 between the seal ring 4 and the annular groove 3, the seal ring 4 contracts at low temperatures, reducing the pressing force against the inner circumferential surface of the first member 1. Alternatively, there was a problem that the sealing effect deteriorated due to separation from the inner circumferential surface.

This can be countered by assembling the seal ring 4 to the first member 1 with a slightly larger tightening allowance S, but on the other hand, by taking a larger tightening allowance S, the sliding resistance increases, and the seal ring There were various drawbacks such as making it difficult to assemble the parts 4 and causing premature wear.

The present invention was devised to eliminate these drawbacks of the conventional seal ring, and its purpose is to prevent the seal ring from shrinking by eliminating the radial gap between the seal ring and the annular groove. The objective is to enhance the sealing effect at low temperatures, and to reduce the sliding resistance by reducing the interference of the seal ring with respect to the first member.

Another object of the present invention is to form an annular passage and a communication passage in the inner hole of the seal ring, and introduce pressure fluid through these passages to stretch the seal ring around the outer periphery to ensure a reliable seal. It is something to do.

Embodiments of the present invention will be described below based on the drawings. In FIG. 2, 10 is a cylindrical fitting hole 11.
12 is a cylindrical second member that is fitted into this fitting hole 11. This second member 1
An annular groove 13 having a width L1 and a diameter D is formed on the outer periphery of the ring 2, into which a seal ring 14 made of a flexible hard resin such as tetrafluoroethylene resin is fitted. The width L2 of this seal ring 14 is made slightly smaller than the width L1 of the annular groove 13, and there is an axial clearance 1 between it and the side wall of the annular groove 13.
6 is secured. Also, this seal ring 14
The diameter D of the inner hole 17 is the diameter D of the annular groove 13.
It is manufactured to have approximately the same dimensions as the annular groove 13, and is fitted into the annular groove 13 so that no radial gap is created between the groove and the bottom wall of the annular groove 13.

The seal ring 14 has an annular shape with an inner hole 18 as shown in FIGS. 3 and 4, and an annular passage 19 is continuously formed in the inner hole 18 in the circumferential direction. A plurality of communication grooves 20 that communicate the annular passage 19 with the axial clearance 16 are formed at equal intervals in the circumferential direction.

In the sealing device having such a configuration, the seal ring 14 is fitted to the bottom wall of the annular groove 13 with almost no radial clearance, and contraction of the seal ring 14 is prevented by this bottom wall. be done.

Furthermore, even if the radial gap between the seal ring 14 and the bottom wall of the annular groove 13 is eliminated, the present invention can actively supply pressure fluid to the annular passage 19 via the axial gap 16 and the communication groove 20. The seal ring 14 is uniformly expanded outward in the circumferential direction by the fluid pressure of this pressure fluid, and as a result, the seal ring 14 is brought into close contact with the inner peripheral surface of the fitting hole of the first member 10, Performs a reliable sealing action.

As detailed above, in this invention, the seal ring is fitted to the bottom wall of the annular groove without any gap, which prevents the seal ring from shrinking and prevents the seal ring from shrinking at low temperatures. This has the advantage that the sealing effect can be enhanced, and the interference of the seal ring with respect to the first member can be reduced, and sliding resistance can be reduced.

Furthermore, since the present invention has a structure in which a communicating passage and an annular passage are formed in the inner hole of the seal ring, pressure fluid is introduced through these passages to uniformly stretch the seal ring outward in the circumferential direction. It has the advantage of being able to reliably prevent leakage of pressure fluid.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a main part showing a conventional sealing device, Fig. 2 is a sectional view of a main part showing an embodiment of the sealing device of the present invention, Fig. 3 is a front view of a seal ring, and Fig. 4 is a sectional view of a main part of a conventional sealing device. It is a sectional view taken along the - line in the figure. 10...first member, 12...second member, 13...
... Annular groove, 14 ... Seal ring, 16 ... Axial clearance, 18 ... Inner hole, 19 ... Annular passage,
20...Communication path.

Claims (1)

[Scope of utility model registration request] An annular groove is carved on the outer periphery of the second member that is slidably fitted to the first member, and a flexible seal ring is attached to the side surface of the annular groove and the side wall of the annular groove. The groove is fitted so that an axial clearance is secured between the inner hole and the bottom wall of the annular groove, and the radial clearance between the inner hole and the bottom wall of the annular groove is almost zero. A sealing device comprising a passage and a communication groove that communicates the annular passage with the axial gap.