Sealing member of a compressor

Abstract

A coat of material impermeable to coolant gas is formed on the surface of a sealing member of a compressor for absorbing and compressing the coolant gas.

Description

BACKGROUND OF THE INVENTION

The present invention relates to a sealing member of a compressor for absorbing and compressing coolant gas.

Japanese Patent Laid-Open Publication No. 2003-246976 discloses a sealing member of a carbon dioxide compressor excellent in impermeability to carbon dioxide.

The prior art disclosed in Japanese Patent Laid-Open Publication No. 2003-246976 provides a sealing member of a compressor suitable for use with a specific coolant gas and does not provide a sealing member of a compressor suitable for use with various kinds of coolant gases.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a sealing member of a compressor suitable for use with various kinds of coolant gases.

In accordance with the present invention, there is provided a sealing member of a compressor for absorbing and compressing coolant gas, wherein a coat of material impermeable to coolant gas is formed on the surface of the sealing member.

A sealing member provided with a coat of material impermeable to coolant gas formed on the surface thereof, can be used in compressors for various kinds of coolant gases.

A coat of soft metal, ceramic, amorphous hard carbon or high polymer material such as polyethylene, polytetrafluoroethylene, or the like is highly impermeable to any kind of coolant gas. Each of the materials has a specific character. Therefore, the most suitable material is desired to be used for the coat considering the working environment of the compressor, working environment of the sealing member, etc.

In accordance with another aspect of the present invention, there is provided a compressor for absorbing and compressing coolant gas comprising a sealing member, wherein a coat of material impermeable to coolant gas is formed on the surface of the sealing member.

When a coat of material impermeable to coolant gas is formed on the surface of the sealing member, impermeability of the sealing member is enhanced to any kind of coolant gas. Therefore, the compressor of the present invention can effectively prevent leakage of coolant gas. The compressor of the present invention can compress various kinds of coolant gases, while effectively preventing leakage of coolant gas.

A coat of soft metal, ceramic, amorphous hard carbon or high polymer material such as polyethylene, polytetrafluoroethylene, or the like is highly impermeable to any kind of coolant gas. Each of the materials has a specific character. Therefore, the most suitable material is desirably used for the coat considering the working environment of the compressor, working environment of the sealing member, etc.

In accordance with a preferred embodiment of the present invention, the compressor further comprises a rotating shaft, a compressing mechanism driven by the rotating shaft, a housing for accommodating the rotating shaft and the compressing mechanism, and a shaft seal member. The sealing member is the shaft seal member.

In accordance with a preferred embodiment of the present invention, the compressor further comprises a rotating shaft, a compressing mechanism driven by the rotating shaft, and a housing for accommodating the rotating shaft and the compressing mechanism. The housing is an assembly of a plurality of partial housings. Gaskets are inserted into joints of the partial housings, and the sealing member is one of the gaskets.

The sealing member is suitably used as a shaft seal member, a gasket, etc.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a sectional view of a variable delivery swash plate compressor provided with a sealing member in accordance with a preferred embodiment of the present invention.

FIG. 2 is a fragmentary sectional view of a variable delivery swash plate compressor provided with a sealing member in accordance with a preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A variable delivery swash plate compressor provided with a sealing member in accordance with a preferred embodiment of the present invention will be described.

As shown in FIG. 1, a variable delivery swash plate compressor A is provided with a rotating shaft 10, a rotor 11 fixed to the rotating shaft 10 and a swash plate 12 supported by the rotating shaft 10 to be variable in inclination relative to the rotating shaft 10. The swash plate 12 is connected to the rotor 11 through a linkage 13 for allowing the swash plate 12 to vary in inclination relative to the rotating shaft 10 and inhibiting the swash plate 12 from rotating around the rotating shaft 10. The swash plate 12 rotates synchronously with the rotor 11 and the rotating shaft 10.

A plurality of pistons 15 engage the swash plate 12 through a plurality of pairs of shoes 14 slidingly engaging the peripheral portion of the swash plate 12. The pistons 15 are inserted in cylinder bores 16a formed in a cylinder block 16.

A front housing 18 of circular cylindrical shape forms a crank chamber 17 for accommodating the rotating shaft 10, the rotor 11 and the swash plate 12. The front housing 18 is closed at one end and provided with a boss 18a at the closed end. The rotating shaft 10 passes through the boss 18a out of the front housing 18 at the front end. An annular space is formed between the rotating shaft 10 and the inner circumferential surface of the boss 18a.

A shaft seal 19 is disposed to seal the annular space between the rotating shaft 10 and the inner circumferential surface of the boss 18a. As shown in FIG. 2, the shaft seal 19 is provided with lip seal members 19a and 19b slidingly contacting the circumferential side surface of the rotating shaft 10 and clamping metals 19c and 19d for clamping and fixing the lip seals 19a and 19b. The lip seal 19a disposed close to the crank chamber 17 is a rubber molding made mainly of hydro-nitrile rubber (HNBR) and is covered by a coat of soft metal such as tin (Sn), alloy metal containing copper (Cu) and tin (Sn), alloy metal containing nickel (Ni) and tin (Sn), alloy metal containing zinc (Zn) and tin (Sn), or the like. The lip seal 19a is provided with a fixed portion 19a′ clamped by the clamping metals 19c and 19d and a movable portion 19a″ slidingly contacting the circumferential side surface of the rotating shaft 10. The lip seal 19b disposed close to one end of the rotating shaft 10 projecting from the front housing 18 is made of a synthetic resin such as polytetrafluoroethylene (PTFE). The lip seal 19b is provided with a fixed portion 19b′ clamped by the clamping metals 19c and 19d and a movable portion 19b″ slidingly contacting the circumferential side surface of the rotating shaft 10. Before the shaft seal 19 is assembled with the boss 18a, the movable portions 19a″ and 19b″ extend inwardly in radial direction as indicated by phantom lines in FIG. 2. After the shaft seal 19 has been assembled with the boss 18a, the movable portions 19a″ and 19b″ are forced against the circumferential side surface of the rotating shaft 10 to slidingly contact the circumferential side surface, thereby sealing the annular space between the rotating shaft 10 and the inner circumferential surface of the boss 18a.

As shown in FIG. 1, an electromagnetic clutch 20 mounted on the boss 18a of the front housing 18 transfers rotating force from external power source not shown in the figures to the front end of the rotating shaft 10.

A cylinder head 21 forming an inlet chamber 21a and an outlet chamber 21b is installed.

A valve plate 22 provided with inlet holes 22a and outlet holes 22b is disposed between the cylinder block 16 and the cylinder head 21. The inlet holes 22a and the outlet holes 22b communicate with the cylinder bores 16a.

The front housing 18, the cylinder block 16, the valve plate 22 and the cylinder head 21 are assembled in a unit by bolts 23.

A gasket 24 is inserted into the joint between the front housing 18 and the cylinder block 16. A gasket 25 is inserted into the joint between the cylinder block 16 and the valve plate 22. A gasket 26 is inserted into the joint between the valve plate 22 and the cylinder head 21. The gaskets 24, 25 and 26 seal the aforementioned joints.

The gaskets 24, 25 and 26 are rubber moldings made mainly of hydro-nitrile rubber (HNBR) or nitrile rubber (NBR). Each of them is covered by a coat of soft metal such as tin (Sn), alloy metal containing copper (Cu) and tin (Sn), alloy metal containing nickel (Ni) and tin (Sn), alloy metal containing zinc (Zn) and tin (Sn), or the like.

The rotating shaft 10 is rotatably supported by the front housing 18 and the cylinder block 16.

The rotor 11, the linkage 13, the swash plate 12, the shoes 14 and the pistons 15 form a compressing mechanism.

The operation of the variable delivery swash plate compressor A in accordance with the present preferred embodiment will be described.

Rotating force is transferred to the rotating shaft 10 from the external power source not shown in the figures through the electromagnetic clutch 20, and rotation of the rotating shaft 10 is transferred to the swash plate 12 through the rotor 11 and the linkage 13. The rotation of the swash plate 12 causes reciprocal movement of the peripheral portion of the swash plate 12 in the longitudinal direction of the rotating shaft 10. The reciprocal movement of the peripheral portion of the swash plate 12 is transferred to the piston 15 through the shoes 14, and the piston 15 moves reciprocally in the cylinder bore 16a. Coolant gas enters into the inlet chamber 21a from an external coolant circuit through an inlet port following the reciprocal movement of the piston 15. The coolant gas is sucked into the cylinder bores 16a through the inlet holes 22a and inlet valves not shown in the figures to be pressurized in the cylinder bores 16a. The pressurized coolant gas in the cylinder bores 16a discharges into the outlet chamber 21b through the outlet holes 22b and outlet valves not shown in the figures, and then discharges from the outlet chamber 21b into the external coolant circuit through an outlet port.

The shaft seal 19 and the gaskets 24 to 26 prevent leakage of the coolant gas from the variable delivery swash plate compressor A.

A coat of soft metal is formed on each of the lip seal 19a and the gaskets 24 to 26. Therefore, they are highly impermeable to various kinds of coolant gases, such as Freon, carbon hydride, alternative Freon, carbon dioxide, ammonia, etc. Therefore, whatever kind of coolant gas is compressed by the variable delivery swash plate compressor A, leakage of the coolant gas from the variable delivery swash plate compressor A is reliably prevented. Hydro-nitrile rubber is easy to obtain because it is used as the material of sealing members of coolant gas compressors. The soft metal is suitable for use on sliding contact parts because it reduces friction resistance.

A coat of ceramic such as silicon carbide (SiC), alumina (Al₂O₃), silicon nitride (Si₃N₄), zirconia (ZrO₂), etc., amorphous hard carbon (DLC), or high polymer material such as polyethylene, polytetrafluoroethylene, etc. may be formed on the surface of the lip seal 19a and the gaskets 24 to 26. The impermeability of the aforementioned seal members to the various coolant gases is enhanced and the ability of the coolant gas compressor to prevent leakage of coolant gas is enhanced.

Ceramic has advantages such as low apparent density, low thermal expansion coefficient, high hardness, high corrosion resistance, non-magnetism, high insulation performance, etc. Especially, silicon nitride has large flexural strength at high temperature and is suitable for use on bearings. Silicon carbide has advantages such as high hardness, large thermal conductivity, high resistance against thermal shock, etc. and is suitable for use on the shaft seal.

Amorphous hard carbon has advantages such as high hardness, low friction coefficient, high ware resistance, high sliding ability, etc. Film thickness and surface roughness can be easily controlled when amorphous hard carbon is coated on the surface of a seal member. Therefore, finishing becomes unnecessary and coating cost decreases.

Polyethylene has advantages such as high thermal stability, high chemical resistance, inexpensiveness, etc. Polytetrafluoroethylene has an advantage in that it decreases friction resistance and is suitable for use on sliding contact parts.

The most suitable material is desirably used for the coat formed on the surface of a seal member considering the working environment of the compressor, working environment of the sealing member, etc.

The present invention can be used for sealing members of any kind of coolant gas compressor.

While the present invention has been described with reference to preferred embodiments, one of ordinary skill in the art will recognize that modifications and improvements may be made while remaining within the spirit and scope of the present invention. The scope of the invention is determined solely by the attached claims.

Claims

1. A sealing member of a compressor for absorbing and compressing coolant gas, wherein a coat of material impermeable to coolant gas is formed on the surface of the sealing member.

2. A sealing member of claim 1, wherein the material of the coat is soft metal.

3. A sealing member of claim 1, wherein the material of the coat is ceramic.

4. A sealing member of claim 1, wherein the material of the coat is amorphous hard carbon.

5. A sealing member of claim 1, wherein the material of the coat is high polymer material.

6. A sealing member of claim 5, wherein the high polymer material is polyethylene.

7. A sealing member of claim 5, wherein the high polymer material is polytetrafluoroethylene.

8. A compressor for absorbing and compressing coolant gas comprising a sealing member, wherein a coat of material impermeable to coolant gas is formed on the surface of the sealing member.

9. A compressor of claim 8, wherein the material of the coat is soft metal.

10. A compressor of claim 8, wherein the material of the coat is ceramic.

11. A compressor of claim 8, wherein the material of the coat is amorphous hard carbon.

12. A compressor of claim 8, wherein the material of the coat is high polymer material.

13. A compressor of claim 12, wherein the high polymer material is polyethylene.

14. A compressor of claim 12, wherein the high polymer material is polytetrafluoroethylene.

15. A compressor of claim 8 further comprising a rotating shaft, a compressing mechanism driven by the rotating shaft, a housing for accommodating the rotating shaft and the compressing mechanism, and a shaft seal member, wherein the sealing member is the shaft seal member.

16. A compressor of claim 8 further comprising a rotating shaft, a compressing mechanism driven by the rotating shaft, and a housing for accommodating the rotating shaft and the compressing mechanism, wherein the housing is an assembly of a plurality of partial housings, gaskets are inserted into joints of the partial housings, and the sealing member is one of the gaskets.