Patent ID: 7111716

Claim:
A power transmission device comprising: a rotary input member adapted to receive drive torque from a power source; a rotary output member adapted to provide drive torque to an output device; a torque transfer mechanism operable for transferring drive torque from said input member to said output member, said torque transfer mechanism including a clutch assembly operably disposed between said input member and said output member and a clutch actuator assembly for applying a clutch engagement force to said clutch assembly, said clutch actuator assembly including an electric motor driving a geared drive unit for controlling said clutch engagement force applied to said clutch assembly by a clutch apply operator, said geared drive unit includes a drive gear driven by said electric motor and first and second face gears with said drive gear in meshed engagement therebetween so as to cause said first and second face gears to rotate in opposite directions in response to driven rotation of said drive gear, said clutch apply operator including a first cam plate fixed for rotation with said first face gear, a second cam plate fixed for rotation with said second face gear and rollers disposed between said first and second cam plates; and a control system for actuating said electric motor so as to control the direction and amount of opposite rotary movement between said first and second face gears which, in turn, controls the direction and amount of translational movement of said first cam plate relative to said clutch assembly so as to vary the clutch engagement force exerted on said clutch assembly.