Rotary expansible chamber devices – Working member has planetary or planetating movement – Helical working member – e.g. – scroll
Reexamination Certificate
2001-05-07
2002-04-30
Vrablik, John J. (Department: 3748)
Rotary expansible chamber devices
Working member has planetary or planetating movement
Helical working member, e.g., scroll
C418S055300, C418S055400, C418S060000, C418S101000, C418S151000
Reexamination Certificate
active
06379134
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a scroll compressor.
Scroll compressors are known in the art. For example, Japanese Patent Laid-Open Publication No.59-65586 discloses a scroll compressor comprising paired fixed and movable scrolls, the fixed scroll of each pair having an end plate provided with a scroll body projecting from the end plate and the movable scroll of each pair having an end plate provided with a scroll body projecting from the end plate, wherein the movable scroll meshes with the fixed scroll to form a plurality of operation chambers between them and revolves relative to the fixed scroll to compress gas in the operation chambers, characterized in that two pairs of fixed and movable scrolls are disposed with back faces of the end plates of the fixed scrolls opposite each other, a main shaft for revolving the movable scrolls passes through the two pairs of fixed and movable scrolls to operatively engage the movable scrolls, and an outlet chamber is disposed between the end plates of the fixed scrolls.
In this known scroll compressor, the main shaft is supported at opposite ends by a housing accommodating the two pairs of fixed and movable scrolls. In the ordinary conventional scroll compressor comprising a pair of fixed and movable scrolls, and a main shaft operatively engaging the movable scroll at its one end, the main shaft is supported at its the other end by a housing accommodating the fixed scroll, the movable scroll and the main shaft. Therefore, the scroll compressor of Japanese Patent Laid-Open Publication No.59-65586 has advantages over the ordinary conventional scroll compressor, including that swirling of the main shaft is restrained, and vibration and noise due to such swirling of the main shaft are restrained.
However, the scroll compressor of Japanese Patent Laid-Open Publication No.59-65586 has following disadvantages.
1. Two movable scrolls are independent of each other. Therefore, anti-rotation mechanisms disposed between the end plates of the movable scrolls and the housing accommodating the scrolls are exposed to thrust load due to the compression of gas in the compression chambers, which causes them to wear and shorten the service life of the compressor. Downsizing of the compressor is difficult because downsizing of the ant-rotation mechanisms exposed to the thrust load is difficult
2. Also owing to the fact that two movable scrolls are independent of each other, adjustment of axial space between the fixed scroll and the movable scroll of one of the two pairs of fixed and movable scrolls must be carried out independently from the adjustment of axial space between the fixed and movable scrolls of the other of the two pairs of fixed and movable scrolls.
3. The main shaft operatively engages the movable scrolls at the central portions of the scroll bodies. Therefore, heat generated by bearings disposed at the operative engagement points is hard to disperse. As a result, the bearings are liable to heat and the service lives of the bearings are liable to become short.
4. No partition is disposed between bearings at the opposite ends of the main shaft and inlet chambers. Moreover, no partition is disposed between bearings at the operative engagement points and the inlet chambers. Therefore, gas taken into the inlet chambers is contaminated with lubricating oil in the bearings and the discharged gas is contaminated with lubricating oil. Therefore, the scroll compressor is not suitable for the compression of clean gas.
5. Also owing to the fact that no partition is disposed between bearings at the opposite ends of the main shaft and inlet chambers and no partition is disposed between bearings at the operative engagement points and the inlet chambers, gas heated by the hot bearings and increased in specific volume is taken into the operation chambers. As a result, flow rate of discharged gas from the scroll compressor is really low.
6. The bearings at the opposite ends of the main shaft and the bearings at the operative engagement points are disposed in substantially closed spaces. Therefore, heat generated by the bearings is hard to disperse, the bearings are liable to heat, and service lives of the bearings are liable to become short.
SUMMARY OF THE INVENTION
Therefore, the object of the present invention is to overcome the foregoing problems by providing a scroll compressor comprising paired fixed and movable scrolls, the fixed scroll of each pair having an end plate provided with a scroll body projecting from the end plate and the movable scroll of each pair having an end plate provided with a scroll body projecting from the end plate, wherein the movable scroll meshes with the fixed scroll to form a plurality of operation chambers between them and revolves relative to the fixed scroll to compress gas in the operation chambers, characterized in that two pairs of fixed and movable scrolls are disposed with back faces of the end plates of the fixed scrolls opposite each other, a main shaft for revolving the movable scrolls passes through the two pairs of fixed and movable scrolls to operatively engage the movable scrolls, and an outlet chamber is disposed between the end plates of the fixed scrolls.
In accordance with the present invention, there is provided a scroll compressor comprising paired fixed and movable scrolls, the fixed scroll of each pair having an end plate provided with a scroll body projecting from the end plate and the movable scroll of each pair having an end plate provided with a scroll body projecting from the end plate, wherein the movable scroll meshes with the fixed scroll to form a plurality of operation chambers between them and revolves relative to the fixed scroll to compress gas in the operation chambers, characterized in that two pairs of fixed and movable scrolls are disposed with back faces of the end plates of the fixed scrolls opposite each other, the movable scrolls are integrally connected with each other, a main shaft for revolving the movable scrolls passes through the two pairs of fixed and movable scrolls to operatively engage the movable scrolls, and an outlet chamber is disposed between the end plates of the fixed scrolls.
In the present scroll compressor, the two movable scrolls integrally connected with each other bear the thrust load accompanying the compression of gas in the operation chambers. Therefore, anti-rotation mechanisms disposed between the end plates of the movable scrolls and a housing accommodating the scrolls and the main shaft do not bear the thrust load. As a result, wear of the anti-rotation mechanisms is minimized and the shortening of the service life of the compressor is minimized. Being free from the thrust load, the anti-rotation mechanisms can be downsized. As a result, the compressor can be downsized.
In the present scroll compressor, the two movable scrolls are integrally connected with each other. Therefore, axial spaces between the fixed scrolls and the movable scrolls of the two pairs of fixed and movable scrolls can be adjusted by a single operation.
According to a preferred embodiment of the present invention, the main shaft operatively engages the movable scrolls at the back faces of the end plates of the movable scrolls.
When the main shaft operatively engages the movable scrolls at the back faces of the end plates of the movable scrolls, the operative engagement points are close to the housing accommodating the two pairs of fixed and movable scrolls. Therefore, heat generated by the bearings at the operative engagement points is able to disperse to outside the compressor. As a result, heating of the bearings at the operative engagement points is suppressed and shortening of the service lives of the bearings is minimized.
According to another preferred embodiment of the present invention, the movable scrolls abut against a housing accommodating the two pairs of fixed and movable scrolls through seal members at peripheral portions of the back faces of the end plates.
Anti-rotation mechanisms and bearings of the main shaft are disposed between the
Sanden Corporation
Vrablik John J.
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