Patent ID: 7862306
Filing Date: 2011-01-04
Classification: F04C

Abstract:
1. A variable displacement engine oil vane pump comprising: pumping chambers defined by slide vanes carried by a rotor rotatable in a housing for pumping engine oil from an inlet to a pressurized outlet; a displacement control for controlling displacement of the pumping chambers, the displacement control including: a cam ring in the housing pivotally connected to a wall of the housing by a pivot, the cam ring being internally engaged by the vanes; a control chamber defined by the cam ring and the housing wall; a control orifice for communicating control oil to the control chamber; a vent chamber generally opposite the control chamber and defined by the cam ring and the housing wall, the vent chamber being generally at atmospheric pressure; a dump chamber defined by the cam ring and the housing wall and being generally disposed between the control chamber and the vent chamber; a dump orifice providing communication between the control chamber and the dump chamber; and a vent orifice providing communication between the vent chamber and the dump chamber; wherein pivotal movement of the cam ring in the housing opens and closes the dump orifice and vent orifice independent of each other at specific positions of the cam ring relative to the housing.