Rotary compressor

Abstract

There is provided a two-stage compression rotary compressor in which the balancer mass of a rotor can be made as small as possible, and the moments that tilt the whole of a shaft can be balanced. The axial length L 2 of a high-stage side crankshaft 72 corresponding to a high-stage compressing section 32 is longer than the axial length L 1 of a low-stage side crankshaft 73 corresponding to a low-stage compressing section 31 (L 2 >L 1 ).

1 . A rotary compressor comprising:
 a closed vessel;   a low-stage compressing section and a high-stage compressing section provided in the closed vessel;   a shaft provided with a low-stage side off-center part and a high-stage side off-center part corresponding to the low-stage compressing section and the high-stage compressing section, respectively;   a motor connected mechanically to the shaft to drive the low-stage compressing section and the high-stage compressing section,   each of the low-stage compressing section and the high-stage compressing section having a cylinder; a piston turning in the cylinder while engaging with the off-center part of the shaft; and a vane the tip end of which comes into sliding contact with the piston while the vane reciprocates in a vane groove in the cylinder to form a suction chamber and a compression chamber for refrigerant together with the cylinder and the piston, and   further comprising:   an intermediate partition plate held between the low-stage compressing section and the high-stage compressing section to close one end surface of the suction chamber and the compression chamber; and   a main frame and a sub-frame each of which is provided with a bearing part for rotatably supporting the shaft and closes one end surface of the suction chamber and the compression chamber, in which   means for allowing the discharge side of the low-stage compressing section and the suction side of the high-stage compressing section to communicate with each other is provided, whereby a two-stage compressing section is formed, wherein   when the axial length of the off-center part of shaft corresponding to the low-stage compressing section is taken as L 1 , and the axial length of the off-center part of shaft corresponding to the high-stage compressing section is taken as L 2 , L 2  is longer than L 1 .   
   
   
       2 . The rotary compressor according to  claim 1 , wherein the rotational speed of the compressing section is variable.