Rotational Coupling Device With Improved Actuator Assembly

A rotational coupling device is provided having an improved actuator for compressing friction discs coupled to an input ring and an output hub disposed about a rotational axis. The actuator includes a pole structure and a field shell housing a conductor, each with aligned, axially extending, radially spaced inner and outer poles. An armature is coupled for rotation with the input ring, but axially movable relative thereto and axially aligned with an end wall of the pole structure extending between the inner and outer actuator poles. First and second axially spaced actuator discs are disposed radially between the pole structure and the output hub with the first actuator disc rotatably coupled to the pole structure. The discs define cam surfaces along which a plurality of balls move to expand and contract the actuator discs upon relative rotation of the actuator discs.