Variable displacement vane pump, component parts and method

Abstract

A durable, single action, variable displacement vane pump capable of undervane pumping, components thereof, and pressure balancing method. The pump comprises a cylindrical barstock rotor member having large diameter journal ends and central vane slots uniformly spaced therearound. The vane slots are elongate and have a central vane-supporting portion of maximum depth surrounded at each end by extension portions having depths which decrease axially to the surface of rotor member. The vaned rotor is rotatably supported within a unitary cam member having opposed faces and a circular bore therethrough forming a cam chamber having a continuous interior circular cam surface. The vane slot extensions in the rotor project outwardly beyond the cam chamber. An opposed pair of manifold bearings rotatably support the journal ends of the rotor and overlap the vane slot extensions to admit fluid to expanding vane bucket areas of the rotating vaned rotor and also into the vane slot extensions and undervane areas for pressure balancing purposes. Fluid passages and pressures within the pump are arranged to balance forces acting on various parts to reduce stress, improve sealing, and permit sharing of a fluid pressure source.