Abstract: A variable displacement mechanism for a scroll type compressor opens and closes a communication path between the suction chamber and a pair of intermediately located sealed spaces. The variable displacement mechanism includes a piston valve member slidably disposed within a cavity. The piston valve selectively opens and closes the communication path between the suction chamber and intermediately located sealed spaces. A conduit permanently links the discharge chamber to the upper end surface of the piston valve so that, even when the communication path is established, the upper end surface of the piston valve is constantly exposed to discharge pressure.

Abstract: A lubricating system for a scroll type compressor is described. The compressor unit includes a housing having a front end plate and a cup shaped casing. A fluid inlet port is formed on the cup shaped casing and has a step portion radially projecting from an inner surface thereof. A first oil passageway is formed through the cup shaped casing with one end opening at the inner wall of the inlet port adjacent to the step portion. A second oil passageway is formed through the front end plate and connects with the first oil passageway. One end of the second oil passageway opens to a shaft seal cavity formed on the front end plate. Therefore, the shaft seal cavity is connected with the fluid inlet port by the first and second oil passageways, and the shaft assembly is lubricated and cooled by lubricating oil and suction gas flowing through the oil passageway.