Patent ID: 6971494

Claim:
A power transmission device comprising: a rotary input member adapted to receive drive torque from a source of drive torque; a rotary output member adapted to transmit drive torque to an output device; and a torque transmission unit operable for transferring drive torque from said input member to said output member, said torque transmission unit including a friction clutch operably disposed between said input member and said output member and a clutch actuator for controlling engagement of said friction clutch, said clutch actuator including a fluid pump, a rotary operator and a thrust mechanism, said fluid pump is operable for generating fluid pressure in proportion to the magnitude of a rotary speed differential between said input and output members, said rotary operator including first and second components defining an actuation chamber therebetween that is adapted to receive the fluid pressure generated by said pump, said first component being fixed for rotation with one of said input and output members and said second component adapted to rotate relative to said first component in response to the fluid pressure in said actuation chamber, and said thrust mechanism is operable for applying a clutch engagement force on said friction clutch in response to rotation of said second component relative to said first component.