Patent ID: 7686149

Claim:
A power transmission device, comprising: a first rotary member adapted to receive drive torque from a power source; a second rotary member adapted to provide drive torque to an output device; a torque transfer mechanism operable for transferring drive torque from said first rotary member to said second rotary member and including a transfer clutch disposed between said first and second rotary members and a clutch actuator for controlling engagement of said transfer clutch, said clutch actuator including an electric motor driving a geared drive unit for converting rotary movement of a clutch apply operator into translational movement of an actuator plate relative to said transfer clutch, said geared drive unit including a pinion gear driven by said electric motor that is meshed with a face gear fixed to said clutch apply operator and having a ramp angle adapted to accommodate translational movement of said face gear relative to said pinion gear; and a control system for actuating said electric motor to control the direction and amount of rotation of said face gear so as to concurrently control the direction and amount of translational movement of said actuator plate relative to said transfer clutch.