VARIABLE DISPLACEMENT PUMP WITH MULTIPLE PRESSURE CHAMBERS

摘要

A variable displacement vane pump has a plurality of seals between the inner surface defining the housing's internal chamber and an outer surface of the control ring. The seals define pressure regulating chambers. A first chamber is defined between a pair of seals located in a circumferential direction of the ring on opposing sides of the pivotal mounting of the ring and has at least one inlet for receiving pressurized fluid. The circumferential extent of the first chamber is greater along a portion for applying force to the ring in a second pivotal direction than along a portion for applying force in the first pivotal direction such that a net force is applied in the second pivotal direction. A second chamber has at least one outlet for receiving pressurized fluid such that the entire circumferential extent of the second chamber applies force to the ring in the second pivotal direction.