Radical actuator for a de-orbiting scroll in a scroll type fluid handling machine

摘要

A scroll compressor (10) with a fixed scroll (18) and orbital scroll (20) has an axial thrust and anti-rotation assembly (22), a drive assembly (24), a balance assembly (26) and a control system (28). The drive assembly (24) includes a crankshaft (116) and a bushing assembly (108). The bushing assembly includes a bushing body (146) with a slot (154) journaled on the orbital scroll and a drive lug (150) positioned in the slot and non-rotatably secured to the crankshaft (116). Springs (156) bias the bushing body toward a position in which the axis of the bushing body (178) coincides with the axis (176) of the crankshaft and the crankshaft can rotate without moving the orbital scroll. The bushing body (146) can be moved by compressed fluid to a position in which the springs (156) are compressed, the scroll wraps (34 and 56) are in sealing contact and the drive assembly will drive the orbital scroll in a circular orbit with a radius R.sub.0. The balance assembly includes two weight assemblies (184 and 186) with four weights (192, 196, 210 and 214) that are rotated about the axis of a cylindrical extension (182) in response to movement of the drive lug (150) relative to the bushing body (146) between a position in which the orbital scroll (20) is balanced and a position in which the weights balance themselves when the crankshaft (116) rotates without driving the orbital scroll. The control system (28) includes a trigger compressor (242) and a solenoid valve (246) which directs compressed fluid to the sump (88) when the solenoid valve is open and to the chamber (162) in the bushing assembly (108) when the solenoid valve is closed.