Seal for a joint or juncture – Seal between fixed parts or static contact against... – Contact seal for a pipe – conduit – or cable
Reexamination Certificate
1999-11-30
2001-11-27
Knight, Anthony (Department: 3626)
Seal for a joint or juncture
Seal between fixed parts or static contact against...
Contact seal for a pipe, conduit, or cable
C277S627000, C277S650000, C277S910000, C277S935000
Reexamination Certificate
active
06322086
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a seal structure of a compressor for use in an air conditioner and so forth.
2. Description of the Related Art
In compressors in general, constituent members that constitute a main housing are joined to one another and are fixed under this state by a plurality of bolts. An O-ring or a gasket seal is interposed into each joint portion in order to prevent pressure reduction.
Japanese Unexamined Patent Publication (Kokai) No. 8-261150 or 9-42156 discloses a seal structure for forming a multiple structure of O-rings or gasket seals. In the latter reference, two O-rings as seal members are interposed into the joint portions between members constituting a main housing. Because two O-rings are interposed, the sealing performance inside the housing can be improved.
However, the seal structure of the prior art is not free from the problem that when a high pressure gas such as carbon dioxide is used as a refrigerant, the carbon dioxide gas is likely to leak from the joint portion through a rubber material even when the O-ring made of the rubber material is constituted into the multiple structure, because carbon dioxide gas can easily permeate through the rubber material.
This problem may be solved by using a rubber material that has heat-resistance, oil resistance, blister resistance and gas permeation resistance in good balance, for the O-ring. However, it is practically difficult to select a material having all these functions, and even if the O-ring has a single-layered structure, the material cost becomes high.
In a multiple stage structure using the conventional rubber material, O-rings having the same diameter are stacked in multiple stages. When the diameter of the O-rings is increased in order to secure sufficient seal performance, the thickness of the housing must be increased at the seal portion, increasing the size of the housing. Even if the diameter of the O-ring is increased, the problem of the gas leak remains unsolved when the refrigerant is carbon dioxide.
SUMMARY OF THE INVENTION
In view of the problems described above, it is an object of the present invention to provide a seal structure of a compressor which structure can secure high sealing performance at joint portions and moreover, has a simple construction, by using seal members made of rubber, even when a refrigerant having relatively high permeability to the rubber materials is used in a compressor.
According to one aspect of the present invention for accomplishing the object described above, a seal structure of a compressor includes seal members made of a rubber and interposed into joint portions between constituent members of a main housing and into joint portions between fitting members fitted into a bore for inserting a rotary shaft and the housing, wherein a plurality of seal members are provided to at least one of the joint portions, a seal member excellent in both mechanical and chemical properties is disposed inside and a seal member excellent in gas permeation resistance is disposed outside, among a plurality of the seal members.
According to another aspect of the present invention, a steal structure of a compressor includes seal members made of a rubber and interposed into joint portions between constituent members of a main housing and into joint portions between fitting members fitted into a bore for inserting a rotary shaft and the housing, wherein a plurality of seal members having mutually different diameters are provided to at least one of the joint portions, a seal member or members having a greater diameter are disposed inside and a seal member or members having a smaller diameter are disposed outside.
According to another aspect of the present invention, the seal member having a greater diameter described above uses a material excellent in both mechanical and chemical properties, and the seal member having a smaller diameter uses a material excellent in gas permeation resistance.
According to still another aspect of the present invention, the constituent members described above comprise a cylinder main body, a front housing and a rear housing, and a plurality of the seal members are provided into the joint portions between the cylinder main body and both housings.
According to still another aspect of the present invention, the seal member is provided into the joint portion between the fitting member and an inner peripheral surface of the housing.
According to still another aspect of the present invention, the refrigerant used for the compressor is carbon dioxide.
According to these embodiments of the present invention, the inner seal member uses a material excellent in mechanical and chemical properties whereas the outer seal member uses a material excellent in gas permeation resistance, and the seal members having mutually different excellent functions can be provided to the joint portions. Consequently, even when the refrigerant gas permeates through the inner seal member, gas leakage is suppressed by the outer seal member, and high seal performance can be secured.
According to still another embodiment of the present invention, the refrigerant is sealed by the seal members in multiple stages, and the seal member having a greater diameter and disposed inside executes a main sealing function. Even when a part of the refrigerant permeates through the inner seal member, it is sealed by the seal member having a smaller diameter and disposed outside. In addition, because the permeation passage of the refrigerant gas passing through this seal member is thinly reduced, seal performance can be improved. Since the outer seal member has a small diameter, the thickness of the joint portion necessary for securing the arrangement space can be reduced to a relatively small thickness.
According to still another embodiment of the present invention, the seal member having a greater diameter, made of a material excellent in mechanical and chemical properties and disposed on the inner side of the joint portion mainly seals the refrigerant. The seal member having a smaller diameter, made of a material excellent in gas permeation resistance and disposed outside, seals the refrigerant gas that leaks from the inner seal member having a greater diameter.
According to still another embodiment of the present invention, high seal performance can be secured at the joint portions between the cylinder main body and both housings even when a refrigerant having relatively high gas permeability to the rubber materials is used.
According to still another embodiment of the present invention, high seal performance can be secured at the joint portions between fitting members fitted to a bore for inserting a rotary shaft and the housing even when a refrigerant having relatively high gas permeability to the rubber materials is used.
According to still another embodiment of the present invention, high seal performance can be secured at the joint portions even when the refrigerant is carbon dioxide.
The present invention may be more fully understood from the description of a preferred embodiment set forth below, together with the accompanying drawings.
REFERENCES:
patent: 3425716 (1969-02-01), Blau
patent: 4441725 (1984-04-01), Bailey
patent: 4789373 (1988-12-01), Adman
patent: 5244355 (1993-09-01), Fujii et al.
patent: 5941530 (1999-08-01), Williams
patent: 6227814 (2001-05-01), Yokomachi et al.
patent: 196 10 060 A (1996-09-01), None
patent: A8-261150 (1996-10-01), None
patent: 09 042156 (1997-02-01), None
patent: A9-42156 (1997-02-01), None
EP 99 12 3736 Search Report dated Oct. 30, 2000.
Fujii Toshiro
Imai Takayuki
Koide Tatsuya
Yokomachi Naoya
Kabushiki Kaisha Toyoda Jidoshokki Seisakusho
Knight Anthony
Peavey Enoch
Woodcock & Washburn LLP
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