Patent ID: 8763777

Claim:
A torque transfer coupling for use in a motor vehicle driveline, the coupling comprising: first and second rotary members; a transfer clutch operatively connected between said first and second rotary members; a piston disposed in a piston chamber and actuable to engage said transfer clutch; a hydraulic pump having a pump inlet in fluid communication with a sump containing hydraulic fluid and a pump outlet in fluid communication with said piston chamber, said hydraulic pump having a first pump member fixed for rotation with said first rotary member and a second pump member fixed for rotation with said second rotary pump member, wherein said first pump member and said second pump member are disposed in eccentric engagement, with said first pump member disposed inward of said second pump member, to define a rotating gap therebetween such that relative rotation between said first and second pump members generates a fluid pumping action for communicating hydraulic fluid from said pump inlet to said pump outlet; a control valve for regulating the pressure of said hydraulic fluid within said piston chamber, said control valve having a valve inlet and a valve outlet in fluid communication with said sump; a first flow path extending at least in part through said hydraulic pump via said rotating gap defined between said first pump member and said second pump member for communicating said hydraulic fluid from said pump inlet to said pump outlet and said piston chamber; and a second flow path extending at least in part through said hydraulic pump including at least one pump member passageway extending through said first pump member for communicating said hydraulic fluid from said piston chamber to said valve inlet of said control valve.