JPH05187550A - Sealing device - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] Relative rotation of the main seal ring and the back seal ring causes the mating points of both rings to align, and the fluid inside the ring groove is low pressure through the mating points of both rings. Prevent it from leaking to the side. [Structure] A main seal ring 2 and a back seal ring 5 are engaged with a concave portion 4 and a convex portion 6 provided on both rings to prevent relative rotation between the main seal ring and the back seal ring. .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal device which is used in a portion of an oil-free compressor or a non-lubricated device which requires high air tightness.

[0002]

2. Description of the Related Art So-called non-lubricated equipment such as oilless compressors, Stirling engines, and Stirling cycle refrigerators have main seal rings and back seals as disclosed in Japanese Utility Model Publication No. 61-94013. A so-called three-piece type sealing device consisting of a ring and an expander ring is used.

This three-piece type sealing device is
As the main seal ring, select a material whose outer peripheral surface does not lubricate the inner wall surface of the cylinder and has good followability, and as the back seal ring, mainly select the material that follows the main seal ring, that is, outward. It is only necessary to select the material for the sealing output mainly for the sealing output, and since the expansion output to the outside is secured by expander ring, high airtightness is exhibited.

In order to maintain the high airtightness of the above-mentioned sealing device, when the sealing device is assembled to the piston or the like, the mating openings of the rings are not aligned. However, the sealing device receives the fluctuation of the fluid pressure on the high pressure side, and the phenomenon of the matching of the abutments is often observed. In particular, if the back seal ring gap overlaps the main seal ring gap, the fluid on the high pressure side escapes from the back seal ring gap to the main seal ring butt gap, and the low pressure side fluid passage Are produced, and the sealing characteristics are significantly deteriorated.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problem of the prior art that the abutment overlaps and to maintain the high sealing performance of the three-piece type sealing device. .

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is basically a technical means for bringing a main seal ring and a back seal ring into an engaged state by a concave portion and a convex portion. To use.

Specifically, according to the present invention, a main seal having an outer peripheral surface in sliding contact with the inner wall surface of the cylinder and having a concave portion (or a convex portion) provided at a position on the inner peripheral surface and apart from the abutment. A ring and a back seal ring inside the main seal ring, the back seal ring having a convex portion (or a concave portion) that is located apart from the mating opening of the main seal ring and that engages with the concave portion. A sealing device having an expander ring located inside a seal ring and applying a force to push the back seal ring outward.

Preferably, the main seal and the back seal ring are made of polytetrafluoroethylene, and the projection has a shape in which a part of the back seal ring is bent outward or a part of the outer peripheral surface thereof is padded. To do.

The shape of the main seal ring is preferably stepped.

[0010]

The engagement between the concave portion and the convex portion of the main seal ring and the back seal ring is performed by exposing the main seal ring to one side surface thereof to high-pressure fluid and sliding the outer peripheral surface thereof against the cylinder inner wall surface. Although it tries to rotate relative to the back seal ring that receives the expansion force of the expander ring, the relative rotation is blocked, and the main seal ring and the back seal ring rotate together.

The recesses and the projections are engaged with each other so that the back seal ring is located at an angle of preferably 90 degrees (angle) to the main seal ring. Position them 180 degrees (angle) apart. The present invention can always maintain this positional relationship.

[0012]

EXAMPLES A sealing device 1 has a main sealing ring 2 made of synthetic resin, preferably polytetrafluoroethylene (PTFE). The main seal ring 2 has a stepped abutment 3, and a recess 4 is formed on the opposite side of the abutment 3, that is, at a position separated by 180 degrees (angle). Inside the main seal ring 2, a back seal ring 5 made of synthetic resin, preferably polytetrafluoroethylene (PTFE) is arranged.
The back seal ring 5 has an outwardly bent convex portion 6 that engages with the concave portion 4 of the main seal ring 2. When the convex portion 6 is engaged with the concave portion 4 of the main seal ring 2,
In order to locate the abutment 7 of the back seal ring 5 at an intermediate portion between the abutment 3 of the main seal ring 2 and the recess 4,
The position of the convex portion 6 is determined.

Inside the back seal ring 5, an expander ring 8 having a spring characteristic that provides an outward tension output is arranged. The expander ring 8 compensates for this with the radial outward force of the high-pressure fluid in the ring groove because both rings 2, 5 have no outward tension force.
The outer peripheral surface of the back seal ring 5 is brought into close contact with the inner wall surface of the cylinder, and the back seal ring 5 is pressed against the inner peripheral side of the main seal ring 2. The position of the gap 9 of the expander ring 8 is not particularly limited, but as shown in FIG.
It may be at the same position as the abutment 3 of.

The back seal ring 5 receives the high-pressure fluid in the direction of the arrow on the wall surface of the ring groove and comes into close contact with the ring groove. As long as it does not overlap the port 3, it will not leak to the low pressure side through the mating port 3 of the main seal ring 2. In the illustrated example, due to the engagement between the concave portion 4 and the convex portion 6, the mating port 7 of the back seal ring 5 does not overlap the mating port 3 of the main seal ring 2, and the fluid leaks around the ring groove. Absent.

The example shown in FIG. 3 is an example in which the convex portion 6'of the back seal ring 5 is used and one portion of the ring body is thick. The thick convex portion 6'has the same function as the convex portion 6 shown in FIG. When the thickness of the back seal ring is large, the back seal ring may be provided with a concave portion, or the main seal ring may be provided with a convex portion so that both are in an engaged state.

[0016]

According to the present invention, only by providing the main and back seal rings with a concave portion and a convex portion in a part thereof, relative rotation of both rings can be prevented without deteriorating the characteristics of the rings. With this simple structure, the high pressure of the fluid that has entered the ring groove can be exerted radially outward from the inner peripheral side of the ring, and the main seal ring can be evenly pressed against the inner wall surface of the cylinder.

[Brief description of drawings]

FIG. 1 is a plan view of an example of the present invention.

FIG. 2 is a perspective view of a mating portion of a main seal ring.

FIG. 3 is a plan view showing another example of the convex portion of the back seal ring.

[Explanation of symbols]

 2 Main seal ring 3 Fitting 4 Recess 5 Back seal ring 6, 6'Protrusion 7 Fitting 8 Expander ring

Front Page Continuation (72) Inventor Yoshiaki Wada 1-37 Hokutocho, Kashiwazaki City, Niigata Riken Kashiwazaki Plant (72) Inventor Hiroyuki Ouchi 2-1, Asahimachi, Kariya City, Aichi Aisin Seiki Co., Ltd. In-house (72) Inventor Shinji Hayashi 2-1-1 Asahi-cho, Kariya city, Aichi Prefecture Aisin Seiki Co., Ltd.

Claims (4)

[Claims] 1. A main seal ring having an outer peripheral surface slidingly contacting an inner wall surface of a cylinder and having a concave portion (or a convex portion) provided at a position on the inner peripheral surface thereof, which is separated from the abutment, and the main seal ring. A back seal ring inside the main seal ring having a convex portion (or a concave portion) which is located apart from the back seal ring and has a convex portion (or a concave portion) which engages with the concave portion, and is located inside the back seal ring. Further, a sealing device having an expander ring that gives a force to push the back seal ring outward. 2. The sealing device according to claim 1, wherein the main seal ring and the back seal ring are made of polytetrafluoroethylene. 3. The sealing device according to claim 2, wherein the convex portion is formed by bending a part of the back seal ring outward. 4. The sealing device according to claim 2, wherein the projection has a shape in which a part of an outer peripheral surface of the back seal ring is built up.