A torque transfer mechanism is provided for controlling the magnitude of a clutch
engagement force exerted on a multi-plate clutch assembly that is operably disposed
between a first rotary and a second rotary member. The torque transfer mechanism
includes a clutch actuator assembly for generating and applying a clutch engagement
force on the clutch assembly. The clutch actuator assembly includes an electric
motor/brake unit, a torque/force conversion mechanism, and a force amplification
mechanism. The motor/brake unit 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. The thrust force generated by the torque/force conversion
mechanism is increased by the force amplification mechanism with the resultant
clutch engagement force applied to the clutch assembly. The dual mode feature of
the electric motor/brake unit significantly reduces the power requirements.