Patent ID: 6692396
Filing Date: 2004-02-17
Classification: B60K,F16H,Y10T

Abstract:
A differential assembly in a motor vehicle, said differential assembly comprising:a differential case to be rotated by an outside drive torque; at least one output shaft drivingly connected to said differential case through a differential gear mechanism; a friction clutch pack for selectively engaging and disengaging said differential case and said output shaft, said clutch pack comprising at least one inner friction plate coupled to rotate with said at least one output shaft and at least one outer friction plate coupled to rotate with said differential case; and a hydraulic clutch actuator for selectively frictionally loading said clutch pack, said actuator comprising: a hydraulic pump for generating a hydraulic pressure to frictionally load said clutch pack; and a variable pressure relief valve assembly to selectively control said friction clutch pack, said variable pressure relief valve assembly including a valve closure member, a valve seat complementary to said valve closure member, and an electro-magnetic actuator for engaging said valve closure member and generating a variable electro-magnetic force urging said valve closure member against said valve seat so as to selectively vary a release pressure of said pressure relief valve assembly based on a magnitude of an electric current supplied to said electro-magnetic actuator, wherein said valve closure member is movable between a closed position when said valve closure member engages said valve seat and an open position when said valve closure member is axially spaced from said valve seat.