A compressor includes a closed container, a compression element disposed in the closed container, and a motor disposed in the closed container to drive the compression element via a shaft. The compression element includes a first and second bearings supporting the shaft. At least one cylinder having at least one cylinder chamber is disposed between the first and second bearings, with at least one roller fitted to the shaft disposed in the at least one cylinder chamber. The first bearing is disposed closer to the motor than the second bearing. The first and second bearings have first and second annular grooves formed in first and second opposing surfaces opposed to end faces of the at least one roller. The first and second annular grooves are opened to the at least one cylinder chamber. A width of the second annular groove is larger than a width of the first annular groove.

A compressor is provided and may include a shell, an orbiting scroll, a driveshaft and an unloader counterweight. The orbiting scroll may be disposed within the shell and include a boss portion. The driveshaft may include an eccentric pin and rotate about a longitudinal axis. The unloader counterweight assembly may include a first, a second end, and a longitudinal opening extending therebetween. The eccentric pin of the driveshaft may be disposed within the longitudinal opening at the first end of the unloader counterweight assembly. The boss portion of the orbiting scroll may be disposed within the longitudinal opening at the second end of the unloader counterweight assembly.

A scroll compressor includes an orbiting scroll member disposed within a compressor housing. The orbiting scroll member has a substantially circular baseplate and a generally spiral wrap extending from its base. A first seal is disposed proximal to the outer periphery of the orbiting scroll baseplate to provide an external seal between the baseplate and the housing. A second seal is disposed radially inward from the first seal to provide an internal seal between the baseplate and the housing. A space between the internal seal and the external seal defines a balance piston chamber. The balance piston chamber is pressurized via a high or intermediate pressure oil source to reduce thrust loading on the baseplate caused by an axial pressure differential across the baseplate.

A scroll compressor is provided which is configured such that an arcuate section may be formed from a suction end of a wrap to a first point to increase a suction volume, and a logarithmic spiral section in which a wrap thickness increases may be formed from a second point to a discharge end of the wrap. This may increase a volume ratio of the compressor so as to increase a capacity of the compressor and prevent damage to the wrap due to a high compression ratio operation, thereby enhancing reliability of the compressor.

A scroll compressor is provided which is configured such that an arcuate section may be formed from a suction end of a wrap to a first point to increase a suction volume, and a logarithmic spiral section in which a wrap thickness increases may be formed from a second point to a discharge end of the wrap. This may increase a volume ratio of the compressor so as to increase a capacity of the compressor and prevent damage to the wrap due to a high compression ratio operation, thereby enhancing reliability of the compressor.

A compression mechanism that can suppress generation of galling and seizure is provided. The compression mechanism includes a bush 60 including a first sliding surface 61 sliding with an inner surface 45a of a bush hole 45 and a second sliding surface 63 sliding with a side surface 52a of a blade of a piston, and includes at least one of a first bulge 62 formed on one of the first sliding surface 61 and the inner surface 45a such that a gap X between the first sliding surface 61 and the inner surface 45a gradually decreases toward a direction in which lubricant Y is drawn between the first sliding surface 61 and the inner surface 45a along with rocking of the bush 60, and a second bulge 64 formed on the second sliding surface 63 such that the gap X between the second sliding surface 63 and the side surface 52a gradually decreases toward a direction in which the lubricant Y is drawn between the second sliding surface 63 and the side surface 52a along with forward and backward movement of the blade.