Torque transfer device having an electric motor/brake actuator and friction clutch

A torque transfer mechanism is provided for controlling the magnitude of a clutch engagement force exerted on a multiplate clutch assembly (80) that is operably disposed between a first rotary member (32) and a second rotary member (42). The torque transfer mechanism includes a clutch actuator assembly (82) for generating and applying a clutch engagement force on the clutch assembly. The clutch actuator assembly includes an electric motor/brake unit (110), a torque/force conversion mechanism (112), and a force amplification mechanism (114). The motor/brake unit (110) can be operated in either of a motor mode or a brake mode to cause bi-directional linear movement of an output member of the torque/force conversion mechanism (112). The thrust force generated by the torque/force conversion mechanism (112) is increased by the force amplification mechanism (114) with the resultant clutch engagement force applied to the clutch assembly (80). The dual mode feature of the electric motor/brake unit (110) significantly reduces the system power requirements.