Patent ID: 7097019

Claim:
A power transmission device comprising: a rotary input member adapted to receive drive torque from a source of torque; a rotary output member adapted to provide drive torque to an output device; and a torque transfer mechanism operable for transferring drive torque from said input member to said output member, said torque transfer mechanism including a friction clutch assembly operably disposed between said input member and said output member and a hydraulic clutch actuation system operable for applying a clutch engagement force to said friction clutch assembly, said hydraulic clutch actuation system including an actuator and an accumulator operable to store pressurized fluid supplied by said actuator, said actuator having a housing, an electromagnet coupled to said housing and a piston slidably positioned within said housing, said piston being biased toward a retracted position by a spring and selectively moveable toward an advanced position during energization of said electromagnet, said actuator being operable to supply pressurized fluid to provide said clutch engagement force.