DIFFERENTIALGETRIEBE UND KUGEL-RAMPEN- BETÄTIGUNGSEINRICHTUNG

A differential gear mechanism including a clutch assembly (35) for retarding rotation between a side gear (23) and a gear case (11,45), and a ball ramp actuator for actuating the clutch assembly. The ball ramp actuator includes an inner actuating plate (49) within the gear case, and an outer actuating plate (51) disposed external to the gear case. In order to initiate ramp up of the ball ramp device, an electromagnetic coil assembly (67) includes an annular coil (75) which is disposed in face-to-face relationship with the outer actuating plate (51). An annular drive plate (83) is disposed between the coil (75) and the outer actuating plate (51), and is drawn into frictional engagement with a layer of friction material (81) upon energization of the coil. The drive plate (83) is connected by pins (89) to be axially movable relative to the outer actuating plate, but fixed to rotate therewith, such that frictional engagement of the drive plate (83) retards rotation of the outer actuating plate (51).