Biased drive mechanism for an orbiting fluid displacement member.

摘要

A fluid displacement apparatus is disclosed. The fluid displacement apparatus includes a housing, a fixed fluid displacement member (20) and an orbiting fluid displacement member (21) having an end plate from which an orbiting wall extends. The orbiting member interfits with the fixed member to make a plurality of line contacts to define at least one sealed-off fluid pocket. A drive shaft (14) is rotatably supported by the housing, and has a drive pin which is radially offset from the axis of the drive shaft. The end plate of orbiting piston member has a boss (213) and bushing (27) is rotatably supported within the boss. The bushing has an eccentric hole disposed eccentrically with respect to the center of the bushing, and the drive pin is inserted in the eccentric hole. A restriction device restricts the swing angle of the bushing and is coupled between the drive shaft and the bushing. The restriction device includes a spring to push the orbiting fluid displacement member in the direction to reduce the orbital radius of the orbiting member. The line contacts between fixed member and orbiting member are thereby separated until the orbiting member reaches a predetermined desired rotational frequency. The compressor thus starts up in an unloaded condition.