Rotary expansible chamber devices – Working member has planetary or planetating movement – Helical working member – e.g. – scroll
Reexamination Certificate
1997-08-13
2001-04-03
Vrablik, John J. (Department: 3748)
Rotary expansible chamber devices
Working member has planetary or planetating movement
Helical working member, e.g., scroll
C418S178000
Reexamination Certificate
active
06210136
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates to a scroll compressor mainly used in professional or commercial and household freezing and air-conditioning systems.
2. Prior Art
In a motor-driven compressor for freezing and air-conditioning, the compression unit is either a reciprocating type or a rotary type of unit. Both types of units are used in the field of freezing and air-conditioning in household and professional or commercial system. At the present time, both types of compressors are growing in use due to their affordable cost and excellent performance. In particular, a scroll type compressor unit is being employed because such a unit is highly efficient, has low noise, and has low vibration.
The scroll compression mechanism used in the scroll compressor, as is well known, includes a fixed scroll and an orbiting scroll, each having vortex blades that are engaged with each other, with several compression chambers formed between them. Each compression chamber compresses a refrigerant by decreasing in volume as the refrigerant the moves from an outer circumferential side in fluid communication with a suction port to an inner circumference side in communication with a discharge port, by an orbiting motion of the orbiting scroll. The compressed refrigerant is discharged from the discharge port.
In order for the orbiting scroll to move in a proper manner to compress the refrigerant, the orbiting scroll is supported by an Oldham ring, which is used to provide an orbiting motion for the orbiting scroll without rotating the orbiting scroll. The Oldham ring is supported by a fixing member that allows the Oldham ring to move.
The Oldham ring slides between the fixing member and orbiting scroll. The orbiting scroll, fixed scroll, fixing member, and Oldham ring are all made of ferriferous materials.
As the refrigerant, specific CFC (chloro-fluoro-carbon) R12 or designate HCFC (Hydro-chloro-fluoro-carbon) R22 has been used. As compared with the refrigerants used in the past, such as sulfur dioxide and methyl chloride, specific CFC is stable chemically, free from toxicity, and has been widely used as an ideal refrigerant for a long period.
Lately, it is disclosed that chlorine atoms, contained in the molecule of specific CFC, destroy the ozone layer. As a result, substitute refrigerants are being developed and used. As practical substitute refrigerants, chlorine-free HFC (Hydro-fluoro-carbon) and similar refrigerants have been proposed (Hydraulic and Pneumatic Technology, June 1994, published by Nippon Kogyo Shuppan).
However, a compressor using such a substitute refrigerant is not expected to have as excellent lubricity as when using the conventional specific CFC. In particular, the substitute refrigerant does not contain chlorine, which acts as a lubricant. Accordingly, the sliding condition is severe, and in the support structure using an Oldham ring for the orbiting scroll as in the prior art, the sliding parts are likely to wear out, shortening the life of the support structure. This is because the substitute refrigerant cannot be expected to lubricate the Oldham ring of the support structure and the sliding parts of the orbiting scroll and fixing member. The oil film is partly cut and a boundary lubrication state tends to occur. As a result, in this boundary lubrication state portion, which forms with the materials being ferriferous, leads to adhesion of the support structure and a shortened life for this structure.
The shortening of the life of the support structure is a particularly serious problem and is fatal in practical use, especially in a maintenance-free compressor operated for a long period. In an enclosed type of compressor, the life of the support structure itself is supposed to equal the life of the entire compressor.
Hence, it is a primary object of the present invention to solve the above problems, and disclose a scroll compressor free from the problems of having a shortened life due to the wearing of the support structure when using chlorine-free substitute refrigerant.
SUMMARY OF THE INVENTION
The scroll compressor of the present invention comprises a motor, an orbiting scroll, a fixed scroll, a compression mechanism installed in an enclosed container, and a refrigerant supplied to the enclosed container from a refrigeration cycle mechanism installed outside of the enclosed container. The refrigerant circulates in the refrigeration cycle mechanism and the enclosed container. The refrigerant is at least one of HFC (hydro-fluoro-carbon). The compression mechanism has a scroll compression mechanism for compressing the refrigerant between an orbiting scroll driven by the motor and a fixed scroll. The compression mechanism comprises an Oldham ring and a fixing member. The Oldham ring acts to support the orbiting scroll and allows the orbiting scroll to make an orbiting motion without rotating about the fixed scroll. The fixing member acts to support and to move or guide the Oldham ring. The Oldham ring slides on both the fixing member and the orbiting scroll. Preferably, the surface of the Oldham ring is formed of a material different from both materials of the fixing member and the orbiting scroll.
The method of manufacturing a scroll compressor according to the invention includes a step of reforming the surface of an Oldham ring, to form the surface of the Oldham ring of a different material from the materials of the fixing member and orbiting scroll.
According to the present invention, when the scroll compression mechanism is put in action by the start of a motor, suction and compression of the refrigerant are repeated to execute a refrigeration cycle. The refrigerant does not contain chlorine and hence, does not destroy the environment. Lubricity is not expected because the refrigerant does not contain chlorine, and a boundary lubrication state will occur between an Oldham ring and both sliding surfaces of the orbiting scroll and fixing member. However, according to the present invention, the Oldham ring slides against a different material of the orbiting scroll, and also slides against a different material of the fixing member. As pointed out in greater detail below, adhesion between the Oldham ring and the orbiting scroll or fixing member is avoided in the portion of the mutual boundary lubrication state. As a result, the life of the support structure of the orbiting scroll by using an Oldham ring having at least a surface of a different material than the other members of the support structure, the life of the members is extended, and a shortening of the life of the support structure can be avoided, even if a chlorine-free substitute refrigerant is used.
Preferably, the Oldham ring has a steam treated layer formed by steam treatment on its surface.
As a variation, the Oldham ring has a steam treated layer on the surface formed by steam treatment, and also a nitrided layer formed on the steam treated layer.
As another variation, the Oldham ring has a steam treated layer on the surface formed by steam treatment, and also, a reformed layer reformed by manganese phosphate formed on the steam treated layer.
As another variation, the Oldham ring has a hardened surface treated by hardening.
As another variation, the Oldham ring has a ceramic layer coating the surface.
As another variation, the Oldham ring has a physical deposition layer of an inorganic material on its surface.
As another variation, the Oldham ring is composed of a nonporous material, and also has a nitrided layer on its surface.
As another variation, the Oldham ring is composed of a nonporous material, and also has a reformed layer reformed by manganese phosphate on its surface.
In each variation mentioned above, the surface material of the Oldham ring is different from the surface materials of the fixing member and orbiting scroll.
By reforming the surface of the Oldham ring, the surface of the Oldham ring is a different material from the surface materials of the fixing member and orbiting scroll.
Therefore, when the Oldham ring is formed of same mate
Hirano Hideo
Kawano Hiroyuki
Oka Hideto
Matsushita Electric - Industrial Co., Ltd.
McDermott & Will & Emery
Vrablik John J.
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