Patent ID: 8118575

Claim:
A variable displacement vane pump, comprising: a rotor having a set of radially extending vanes; a control ring having an inner surface against which the vanes abut, adjacent vanes forming pumping chambers with the control ring and the rotor and the control ring being moveable about a pivot to alter the eccentricity between the rotation center of the vanes and the rotation center of the control ring to change the displacement of the pump; an inlet port to introduce working fluid from a pump inlet to the pumping chambers; a discharge port located downstream of the inlet port, with respect to the direction of rotation of the rotor, to transfer pressurized working fluid from the pumping chambers to a pump outlet; and a discharge recess formed in at least one of the upper and lower surfaces of the control ring adjacent the discharge port and in fluid communication with the discharge port to form an enhanced discharge port, wherein the discharge recess is in fluid communication with a second discharge port, the second discharge port being in fluid communication with the pump outlet.