Rotary expansible chamber devices – Working member has planetary or planetating movement – Helical working member – e.g. – scroll
Reexamination Certificate
2000-05-25
2001-05-15
Denion, Thomas (Department: 3748)
Rotary expansible chamber devices
Working member has planetary or planetating movement
Helical working member, e.g., scroll
C464S103000
Reexamination Certificate
active
06231325
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a scroll-type compressor.
2. Description of Related Art
A scroll-type compressor includes a first scroll member and a second scroll member within a housing. The first scroll member is provided as a fixed scroll member. The second scroll member is provided as an orbital scroll member for nonrotatable, orbital movement relative to the first scroll member. The rotation of the second scroll member is prevented by rotation preventing mechanism provided in the compressor. The first scroll member has a first end plate and a first spiral element which axially extends from the first end plate. The second scroll member has a second end plate and a second spiral element which axially extends from the second end plate. The first spiral element and the second spiral element interfit at an angular and radial offset to make a plurality of line contacts which define at least one pair of sealed off fluid pockets. The sealed off fluid pockets move radially inwards due to the nonrotatable, orbital movement of the second scroll member, and decrease in volume, thereby, compressing the fluid.
A ball coupling-type mechanism may be used as the rotation preventing mechanism for the second scroll member. In a usual ball coupling-type rotation preventing mechanism, a ring for regulating balls and thrust plates for receiving balls are made separately. In a rotation preventing mechanism having such a structure, a shim generally is used for adjusting an axial gap between the first and second scroll members. In this structure, by selecting an appropriate thickness of the shim, the compressor may be assembled, so that a preload is not generated in the rotation preventing mechanism and between the first and second scroll members within a range that does not affect the performance of the compressor.
A scroll-type compressor has been proposed that uses a rotation preventing mechanism, wherein the ring for regulating balls and the thrust plates for receiving balls are made integrally. Such a ball coupling has a pair of rolling ball regulating plates, each integrally formed as a ring-like plate, and a plurality of balls interposed between the rolling ball regulating plates. The ball coupling is disposed between the second scroll member and a fixed portion of the compressor, such as a front housing facing the second scroll member, so that the pair of rolling ball regulating plates axially face each other. Each rolling ball regulating plate has a plurality of ball rolling grooves that are disposed in the circumferential direction about the plate. Each ball rolling groove may be formed as a ring-like groove. Each ball is disposed between the respective ball rolling grooves of the respective plates, and rolls along the ball rolling grooves during the operation of the compressor for allowing the nonrotatable, orbital movement of the second scroll member. Such a ball coupling has a small number of parts.
However, the rolling ball regulating plate of such a ball coupling generally has a problem that a deformation, such as a distortion or a torsion, is easily generated. For example, a torsion of a single rolling ball regulating plate itself, or a distortion occurring when the ball coupling is assembled, may be generated. In such a condition, it is difficult to properly adjust an axial gap between the first and second scroll members to achieve a desired performance of the compressor. Further, because it is difficult to place the balls at proper positions in the respective ball rolling grooves, the behavior of the balls is unstable. Subsequently unstable behavior of the balls will induce chipping of the plate or generation of noise.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved structure for a scroll-type compressor, which can properly adjust an axial gap between first and second scroll members, using a ball coupling as a rotation preventing mechanism for the second scroll member in which a ring for regulating balls and thrust races for receiving balls are made integrally.
It is another object of the present invention to provide an improved structure for a scroll-type compressor which can stabilize the behavior of the balls of the ball coupling during the operation of the compressor.
To achieve the foregoing and other objects, a scroll-type compressor according to the present invention is herein provided. The scroll-type compressor includes a first scroll member disposed within a housing and having a first end plate from which a first spiral element axially extends into an interior of the housing, and a second scroll member disposed for nonrotatable, orbital movement relative to the first scroll member within the interior of the housing and having a second end plate from which a second spiral element axially extends into the interior of the housing. The first and second spiral elements interfit at an angular and radial offset to make a plurality of line contacts which define at least one pair of sealed off fluid pockets for the compression operation of the compressor. The scroll-type compressor comprises a ball coupling provided as a rotation preventing mechanism for the second scroll member. The ball coupling has a pair of integrally formed rolling ball regulating plates and a plurality of balls disposed between the rolling ball regulating plates. The ball coupling is assembled in the scroll-type compressor in a condition that an axial preload is provided. The axial preload is more than an axial force given by the balls to the rolling ball regulating plates during operation of the scroll-type compressor, for correcting a deformation of the rolling ball regulating plates.
In the scroll-type compressor, the axial preload may remain in the ball coupling as a residual pressure source, even after the balls correct the deformation of the rolling ball regulating plates during operation of the scroll-type compressor.
The rolling ball regulating plates may have ring-like ball rolling grooves for receiving the balls on respective surfaces facing each other. The ball coupling is disposed between the second scroll member and a fixed portion of the scroll-type compressor, such as a portion of a front housing, in an axial direction of the scroll-type compressor.
The scroll-type compressor is incorporated into a refrigerating circuit. The residual pressure is within a range determined by a life of the scroll-type compressor, a coefficient of performance of a refrigerating cycle of the refrigerating circuit, and a volumetric efficiency of the scroll-type compressor.
In the scroll-type compressor according to the present invention, because a desired axial preload is given to the ball coupling, an axial gap between the first and second scroll members may be easily and properly adjusted, thereby, achieving a desired performance of the scroll-type compressor.
Moreover, because the balls correct the deformation of rolling ball regulating plates during the operation of the compressor and the residual axial preload remains even after the correction of the deformation, the behavior of the balls is stabilized, thereby, preventing chipping of the plate or generation of noise.
Further objects, features, and advantages of the present invention will be understood from the following detailed description of a preferred embodiment of the present invention with reference to the accompanying figures.
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Kitano Norio
Tsurutani Kanetsugu
Baker & Botts L.L.P.
Denion Thomas
Sanden Corporation
Trieu Theresa
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