Variable capacity type vane pump with a variable restriction orifice

Abstract

A variable capacity type vane pump comprising a cam ring, a rotor placed for rotation within the cam ring. The rotor has a number of radial slots, and vances placed for radial inward and outward movement in the receptive slots each having a bottom. A pump chamber is defined between the cam ring and the rotor and it has an inlet and outlet port. The outlet port is connected through a conduit to the bottom of at least one of the slots having vanes moving inwardly in the respective slots. A restriction orifice is placed in the conduit. The cam ring is moved with respect to the rotor to vary the capacity of the vane pump in response to a pressure differential across the restriction orifice.