Scroll type compressor with variable displacement mechanism

Abstract

A scroll type compressor with a variable displacement mechanism is disclosed and includes a housing having an inlet port and an outlet port. A fixed scroll is fixedly disposed within the housing and has a first circular end plate from which a first spiral element extends. An orbiting scroll includes a second spiral element interfitting with the spiral element. The first circular end plate partitions an inner chamber of the compressor housing into a front suction chamber linked to the inlet port, and a rear chamber. The rear chamber is further divided by a wall of said housing into a discharge chamber linked to the fluid outlet port and an intermediate pressure chamber. At least one pair of holes is formed through the circular end plate of the fixed scroll forming a fluid channel between fluid pockets formed between the spiral elements of the scrolls and the intermediate pressure chamber. A communicating channel is formed through the circular end plate of the fixed scroll providing a fluid channel which links the intermediate pressure chamber with the front chamber. A control mechanism is disposed in the housing of the compressor adjacent the intermediate pressure chamber and controls the link of the intermediate pressure chamber to the suction chamber. The control mechanism includes a piston slidably disclosed within a cylinder, and a bellows element disposed within the piston. The bellows element includes a bellows and a valve element and is responsive to the suction pressure to control the link between the suction chamber and the central fluid pocket. The piston element is responsive to the pressure in the central fluid pocket to control the link between the intermediate pressure chamber and the suction chamber to control the capacity of the compressor.