Patent ID: 7546895
Filing Date: 2009-06-16
Classification: B62D,F04C

Abstract:
1. A variable displacement pump comprising: a rotor fixed to a pump shaft inserted to a pump casing so as to be rotationally driven, and structured such that a plurality of vanes are accommodated in grooves so as to be movable in a radial direction; a cam ring fitted to a fitting hole within a pump casing so as to be movable and displaceable, forming a pump chamber with respect to an outer peripheral portion of the rotor; an energizing force applied to the cam ring to maximize a volumetric capacity of the pump chamber; a side plate accommodated within the pump casing and brought into slidable contact with one side of the rotor and the cam ring; a cover closing an opening of the pump casing and brought into slidable contact with the other of the rotor and the cam ring; a high pressure chamber formed at a position facing to a discharge region of the pump chamber between a back surface of the side plate and the pump casing and introducing a pump discharge side pressure oil; a low pressure chamber formed at a position facing a suction region of the pump chamber between the back surface of the side plate and the pump casing, and communicating with the suction region of the pump chamber; and an annular seal member interposed between the back surface of the side plate and the pump casing, and surrounding the low pressure chamber together with a lubricating oil path around the pump shaft, wherein the annular seal member is provided with a bridge portion connecting both ends of a U-shape of an approximately U-shaped portion of the annular seal member along the lubricating oil path around the pump shaft.