Abstract: A scroll compressor includes a stationary scroll member accommodated in a closed housing and having a stationary end plate and a stationary scroll wrap protruding axially from the stationary end plate, and also includes an orbiting scroll member accommodated in the closed housing and having an orbiting end plate and an orbiting scroll wrap protruding axially from the orbiting end plate so as to engage with the stationary scroll wrap to define a plurality of working pockets therebetween. A volume ratio indicating a ratio of the volume of the working pockets at an end of suction to that at an end of compression is set to be smaller than a value corresponding to a compression ratio determined by an evaporation pressure and a condensation pressure at a performance half a rated performance during heating.

Abstract: A scroll compressor includes a stationary scroll member accommodated in a closed housing and having a stationary end plate and a stationary scroll wrap protruding axially from the stationary end plate, and also includes an orbiting scroll member accommodated in the closed housing and having an orbiting end plate and an orbiting scroll wrap protruding axially from the orbiting end plate so as to engage with the stationary scroll wrap to define a plurality of working pockets therebetween. A crankshaft is provided to drive the orbiting scroll member, and the crankshaft includes a main shaft and an auxiliary shaft on opposite sides thereof. A main bearing supports the main shaft of the crankshaft. A bearing frame is secured to an inner surface of the closed housing, and an auxiliary bearing is mounted to the bearing frame to support the auxiliary shaft of the crankshaft.

Abstract: A scroll compressor comprises a generally cylindrical casing and stationary and orbiting scrolls both accommodated in the casing. The stationary and orbiting scrolls engage with each other to define a plurality of compression chambers therebetween. The orbiting scroll is driven by a drive shaft which is in turn supported by a frame having a thrust bearing formed thereon. One of an orbiting end plate of the orbiting scroll and the thrust bearing has an annular groove defined therein in which an annular seal member is received. The orbiting scroll is disposed between the stationary scroll and the frame with an axial gap defined therebetween. First, second, and third back chambers are formed on the opposite side of the compression chambers with respect to the orbiting end plate. The first and second back chambers are partitioned by the annular seal member.