Patent ID: 7857723

Claim:
A transaxle unit comprising: a differential assembly having a differential mechanism disposed in a differential case and two opposite output axle shafts outwardly extending from said differential case; a power take-off unit drivingly coupled to said differential case; a torque-coupling device for selectively restricting differential rotation of said differential mechanism; said torque-coupling device including: a friction clutch assembly for selectively frictionally engaging and disengaging said differential case and one of said output axle shafts, said clutch assembly comprising at least one first friction member non-rotatably coupled to said differential case and at least one second friction member non-rotatably coupled to one of said output shafts, said friction members being frictionally engageable with one another; and a hydraulic clutch actuator for selectively frictionally loading said friction clutch assembly, said actuator comprising: a hydraulic pump to generate a hydraulic pressure to frictionally load said friction clutch assembly; and a variable pressure relief valve assembly fluidly communicating with said hydraulic pump to selectively control said hydraulic pressure, 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 power take-off unit is mounted between said differential assembly and said torque-coupling device.