Rotary expansible chamber devices – Working member has planetary or planetating movement – With relatively movable partition member
Reexamination Certificate
2000-02-09
2001-10-09
Vrablik, John J. (Department: 3748)
Rotary expansible chamber devices
Working member has planetary or planetating movement
With relatively movable partition member
C418S152000, C418S178000, C428S408000, C428S610000, C428S634000
Reexamination Certificate
active
06299425
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a member having a sliding contact surface, a compressors and a rotary compressor respectively incorporating the member.
2. Description of Related Art
The rotary compressors for use in refrigerating facilities, air-conditioning equipments and the like have been placed under heavier duty conditions with their recent improvements in performance and capability.
In such rotary compressors, a leading end of a vane is brought into constant contact with a peripheral sliding portion of a roller such as by biasing means. This disadvantageously produces sludges interior of a cylinder housing, the vane and the roller. These sludges cause blockages in a refrigeration system, specifically in a capillary tube to result in a reduced refrigeration capability of the system.
When the situation goes worst, it possibly becomes impossible to supply a refrigerant carrier through the capillary tube to thereby give a destructive damage to the rotary compressor.
Accordingly, there remains a need to provide a member having a sliding contact surface, such as for use in compressors, rotary compressors and the like, which produces less sludges and has an improved wear resistance relative to conventional members and which can be steadily used for a prolonged period of time.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a member having a sliding contact surface which has a superior wear resistance and is steadily workable for a long period of time, and to provide a compressor and a rotary compressor using such a member.
In accordance with a first aspect of the present invention, a member is provided which includes a main body having a sliding contact surface, a hard carbon film provided on the sliding contact surface and a mixed layer formed within a thickness region of the main body adjacent to the sliding contact surface. The mixed layer is comprised of carbon and a constituent element present in the thickness region of the main body and has a carbon content gradient in its thickness direction so that a carbon content in a thickness portion thereof closer to an outer surface of the mixed layer is higher than in a thickness portion thereof remoter from the outer surface of the mixed layer.
In a preferred embodiment of the invention in accordance with the first aspect, the mixed layer is formed by introducing carbon into the region within the main body and adjacent to the sliding contact surface thereof.
The member in accordance with the first aspect has the hard carbon film on the sliding contact surface to exhibit an excellent wear resistance. Also, the formation of the mixed layer adjacent to the sliding contact surface of the main body provides a good adherence of the main body to the hard carbon film so that the member can be steadily used for a prolonged period of time without experiencing delamination.
In accordance with a second aspect of the present invention, a member is provided which includes a main body having a sliding contact surface, an interlayer provided on the sliding surface of the main body, a hard carbon film provided on the interlayer and a mixed layer formed within a thickness region of the interlayer and adjacent to an outer surface of the interlayer. The mixed layer is comprised of carbon and a constituent element of the interlayer and has a graded carbon content in its thickness direction so that a carbon content in a thickness portion closer to an outer surface of the mixed layer is higher than in a thickness portion remoter from the outer surface of the mixed layer.
In a preferred embodiment in accordance with the second aspect, the mixed layer is formed by introducing carbon into an interlayer region adjacent to the outer surface of the interlayer.
The interlayer may be formed of Si, Ti, Zr, Ge, Ru, Mo, W, or oxides, nitrides or carbides thereof, for example.
The member in accordance with the second aspect provides the hard carbon film on the sliding contact surface through the interlayer to exhibit a superior wear resistance. The formation of the interlayer between the hard carbon film and the main body provides an improved adhesion between the hard carbon film and the main body. Also, the formation of the mixed layer within the interlayer adjacent to its outer surface imparts a further improvement in the adhesion of the hard carbon film.
The term “present invention” will be hereinafter used to explain the matters common to the first and second aspects of the present invention.
In the present invention, the mixed layer is formed adjacent to the sliding contact surface of the main body or to the outer surface of the interlayer. The thickness of the mixed layer is preferably not less than 5 Å, more preferably in the range of 5 Å-1 &mgr;m, still more preferably in the range of 10 Å-200 Å. If the mixed layer is thinner, the expected improvement in adhesion may not result. If the thickness of the mixed layer exceeds 1 &mgr;m, the adhesion can not be necessarily improved in proportion to the thickness increment.
In the present invention, the mixed layer has a carbon content gradient in its thickness direction so that a carbon content in a thickness portion thereof adjacent or closer to its outer surface is higher than in a thickness portion thereof opposite to or remoter from its outer surface. The mixed layer has a concentrated portion having a maximum carbon content within the mixed layer. Such a concentrated portion is preferably present on the outer surface of the mixed layer or within a thickness region occupying 50% or less of a total thickness of the mixed layer from its outer surface. The carbon content in the concentrated portion of the mixed layer is preferably not smaller than 20 atomic percent, more preferably not smaller than 40 atomic percent.
As described above, it is preferable to form the mixed layer by introducing carbon into the region within the main body adjacent to its outer surface or into the region within the interlayer adjacent to its outer surface. Such an introduction of carbon can be effected by imparting a kinetic energy to active species of carbon such as carbon ions and allowing them to strike on the outer surface of either the main body or the interlayer. Specifically, the carbon introduction can be effected by allowing the carbon ions to strike on an outer surface of a substrate to which a negative self-bias voltage is being applied.
The hard carbon film in the present invention may comprise a diamond thin film, a film having a mixed diamond and amorphous structure, or an amorphous thin carbon film. The film having the mixed structure and the amorphous carbon film are those generally termed as diamond-like carbon films. The diamond-like carbon film generally contains hydrogen. The diamond-like film with a smaller hydrogen content exhibits an increased hardness and improved wear resistance. On the other hand, the diamond-like carbon film with a larger hydrogen content exhibits an reduced internal stress and improved adherence to an underlayer. It is accordingly preferred that the hard carbon film in accordance with the present invention has a hydrogen content gradient in its thickness direction so that a hydrogen content in a thickness portion thereof remoter from its outer surface is higher than in a thickness portion thereof closer to its outer surface. The provision of such a hydrogen content gradient imparts to the resulting hard carbon film the improved wear resistance and adherence to the underlayer. In the present invention, the hard carbon film may contain at least one additive element selected from the group consisting of Si, N, Ta, Cr, F and B. The inclusion of such an additive element results in a reduced friction coefficient and enhanced wear resistance of the hard carbon film. The inclusion of the additive element is preferably in the range of 3-60 atomic percent, more preferably in the range of 10-50 atomic percent. It is also preferred that the hard carbon film has a content gradient of the addit
Domoto Yoichi
Hirano Hitoshi
Kuramoto Keiichi
Tojo Naoto
Arent Fox Kintner & Plotkin & Kahn, PLLC
Sanyo Electric Co,. Ltd.
Vrablik John J.
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