JP2831527B2 - 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 which makes the most of the low friction loss characteristic of polytetrafluoroethylene resin and does not cause creep deformation.

[0002]

2. Description of the Related Art A seal ring is mounted on a piston outer peripheral surface of a piston for operating a multi-plate clutch of an automobile transmission or a compressor piston in order to secure a seal between a reciprocating piston and a cylinder. This seal ring is often made of a polytetrafluoroethylene resin (PTFE resin) material having low friction loss.

[0003]

[Problems to be solved by the present invention] As shown in FIG.
The seal ring 1 made of PTFE resin has a rectangular cross section and has a not-shown opening. The seal ring 1 is mounted in a ring groove of the piston 2, and its outer peripheral surface is in sliding contact with the inner peripheral surface of the cylinder 4. The reciprocating motion of the piston 2 changes the volume of the compression chamber 3 and causes the suctioned fluid to be discharged at a high pressure.

As shown in FIG. 3, the piston 2 moves up,
During the compression stroke in which the fluid in the compression chamber 3 is brought into a high-pressure state, the seal ring 1 directly and repeatedly receives this high-pressure fluid at a constant cycle, so that the creep deformation occurs in the gap between the piston outer peripheral surface and the cylinder inner peripheral surface. Occurs. The creep deformation of the seal ring 1 increases the contact area between the seal ring and the inner peripheral surface of the cylinder, and increases the friction loss. This increases the reciprocating resistance of the piston 1 and increases the mechanical loss. In addition, the creep deformation of the seal ring 1 expands the abutment, so that the leakage amount of the high-temperature fluid increases, and a high-pressure fluid of a predetermined value cannot be obtained. Therefore, it cannot function as a vehicle transmission or a compressor.

Accordingly, an object of the present invention is to solve the above-mentioned disadvantages of the prior art.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention basically has a technical problem of fixing an outer ring made of PTFE resin to an inner ring using a screw connection and an adhesive connection. Use means. Preferably, the inner ring is made of steel, cast iron, copper, PEEK resin, PI resin, P
A resin or phenol resin.

[0007]

[Function] Since the inner ring and the outer ring are fixed using screws and an adhesive, they are integrated even though they are different materials, so that the low friction loss characteristics of the PTFE resin can be maximized and creep deformation can be eliminated. .

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. The seal ring 5 attached to the ring groove of the piston 2 includes an outer ring 6 made of PTFE resin and any one of steel, cast iron, copper, PEEK resin, PI resin, PA resin, and phenol resin, that is, And an inner ring 7 made of a material other than PTFE resin. The piston 2 and the cylinder 3 are made of an aluminum alloy. A female screw is formed on the inner peripheral surface of the outer ring 6, and a male screw is formed on the outer peripheral surface of the inner ring 7. At this time, apply an adhesive to the screw surface,
The two rings 6 and 7 are added to the screw connection 8 and the adhesive connection 9 is made.

The adhesive requires a thermosetting treatment, and
When the difference between the coefficients of thermal expansion of the materials of the rings 6 and 7 (the coefficient of thermal expansion of the inner ring is smaller than that of the outer ring) is large, an iron-based pipe is fitted on the outside of the outer ring 6 and the screw is fixed during the heat curing of the adhesive. The engagement of the connection 8 is prevented.

[0010] The connecting surface between the outer ring 6 and the inner ring 7 is preferably located in a gap between the piston 2 and the cylinder 3 so as not to enter the ring groove.

Next, an experimental example will be introduced. PTFE resin material with outer diameter 85φ, inner diameter 79φ, width 30mm, outer diameter 81φ,
Using a PEEK resin material with an inner diameter of 75φ and a width of 30 mm, a female thread of M80 pitch 0.7 is cut on the inner peripheral surface of the former, and a male screw of M80 pitch 0.7 is cut on the outer peripheral surface of the latter.
A ring having an outer diameter of 84φ, an inner diameter of the inner ring 7 of 76φ, and a dimension of the screw connection 8 of 80φ was formed. An epoxy-based adhesive was applied to the screw joint 8 to form an adhesive joint 9, an iron pipe was fitted, and a heat-curing treatment of the adhesive was performed at 120 ° C. for 30 minutes. Thereafter, an annular ring having a width of 2 mm and a thickness of 4 mm was manufactured by machining, and finally, the abutment was processed with a straight cutter to form a seal ring 5 as an example of the present invention, which was used as the ring of the present invention.

Separately, a seal ring having the same dimensions as the above was formed from a PTFE resin material, and this was used as a conventional ring. The conventional ring and the ring of the present invention were mounted on a piston of 4000 revolutions and tested with a pump that generates a hydraulic pressure of 8 kg / cm ^2. As shown in FIG.
While the friction increased about 1.7 times at the beginning of operation, the ring of the present invention maintained the initial value and showed constant friction even after 500 hours. Furthermore, there was no displacement between the bonding surfaces 8 and 9, and no creep deformation was observed.

[0013]

According to the present invention, the sliding contact portion with the cylinder can be made of a low friction material, and the inner portion can be made of a strength member. Therefore, it is possible to provide a seal ring that can withstand high pressure.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view showing the use of a seal ring according to an example of the present invention.

FIG. 2 is a graph showing friction between a ring of the present invention and a conventional ring.

FIG. 3 is a partial cross-sectional view showing a usage state of a conventional example.

[Explanation of symbols]

 2 Piston 3 Cylinder 5 Seal ring 6 Outer ring 7 Inner ring 8 Screw connection 9 Adhesive connection

Claims (2)

(57) [Claims] 1. A seal ring having an outer ring made of polytetrafluoroethylene screwed to an inner ring, wherein both rings are joined by an adhesive with a screw portion. 2. The inner ring is made of steel, cast iron, copper, P
2. The seal ring according to claim 1, wherein the seal ring is made of any one of EEK resin, PI resin, PA resin, and phenol resin.