A power transmission device includes 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 to transferring drive torque from the input member to
the output member. The torque transfer mechanism includes a friction
clutch assembly operably disposed between the input member and the output
member and a hydraulic clutch actuation system operable for applying a
clutch engagement force to the friction clutch assembly. The hydraulic
clutch actuation system includes an electric motor drivingly coupled to a
first piston. The first piston is slidably positioned within the housing
for supplying pressurized fluid to an accumulator. The pressurized fluid
within the accumulator is in communication with a second piston to
provide the clutch engagement force.