Scroll fluid machine

Abstract

A scroll fluid machine comprises a housing, two fixed scrolls each of which is fixed on each side of the housing, an endless transmitting member connected to an electric motor, a driven pulley wound by the transmitting member, a thrust-offsetting shaft rotatably mounted at a position eccentric from a axis in the driven pulley, two orbiting scrolls each of which is fixed at each end of the thrust-offsetting shaft which rotates to form a compression chamber with the fixed scroll, and a self-rotation preventing device disposed between the housing and the orbiting scroll.

1 . A scroll fluid machine comprising:
 a housing;   two fixed scrolls each of which is fixed to each side of the housing and has a fixed wrap;   an endless transmitting member connected to an external electric motor;   a cylindrical driven pulley disposed between the two fixed scrolls in the housing and rotating around a first axis by the electric motor via the transmitting member;   a thrust-offsetting shaft rotating around a second axis deviating from the first axis of the pulley;   two orbiting scrolls each of which has an orbiting wrap and revolves with the thrust-offsetting shaft which offsets thrusts acting to the two orbiting scrolls, the thrust-offsetting shaft rotating with rotation of the driven pulley to form a compression chamber between the fixed wrap and the orbiting wrap engaging with each other; and   a self-rotation-preventing device disposed between the housing and the orbiting scroll, the thrust-offsetting shaft rotating to allow the orbiting scroll to orbit while the orbiting scroll is prevented by the self-rotation-preventing device from rotating on the second axis.   
     
     
         2 . The scroll fluid machine of  claim 1 , further comprising a bearing for supporting the thrust-offsetting shaft rotatably in the driven pulley. 
     
     
         3 . The scroll fluid machine of  claim 1  wherein a cover for covering an outer circumference of the driven pulley in the housing has an opening enabling the transmitting member to be wound on the driven pulley from outside of the housing. 
     
     
         4 . The scroll fluid machine of  claim 3  wherein a part that has no opening of the cover acts as a connection connecting the two fixed scrolls, a relief being formed close to and in parallel with an inner surface of the transmitting member. 
     
     
         5 . The scroll fluid machine of  claim 3  wherein a reinforcement member is provided in the cover of the housing to cover the opening. 
     
     
         6 . The scroll fluid machine of  claim 1  wherein the transmitting member comprises a belt.