Disconnecting differential mechanisms for motor vehicles

A disconnectable differential assembly for a vehicle, comprising:

• a power transfer mechanism driven by an electric motor;
• a differential mechanism drivingly connected to a pair of ground-engaging wheels;
• a power-operated disconnect mechanism operable in a disconnected mode to uncouple the power transfer mechanism from the differential mechanism and in a connected mode to couple the power transfer mechanism to the differential mechanism;
• and
• a control system for controlling operation of the electric motor and the power-operated disconnect mechanism;
• wherein the power transfer mechanism includes a ring gear driven by the electric motor and an outer housing fixed to the ring gear to define an internal cavity, wherein the differential mechanism is rotatably supported within the internal cavity and includes a differential carrier and a gearset driven by the differential carrier, and wherein the power-operated disconnect mechanism includes a clutch unit operably disposed between the outer housing and the differential carrier and an electromagnetic actuator unit operable for shifting the clutch unit between a released state whereat the disconnect mode is established and an engaged state whereat the connected mode is established;
• wherein the clutch unit includes a first clutch member associated with the differential carrier and having clutch teeth, and a second clutch member having dog teeth and being coupled for common rotation with the outer housing and axially moveable relative to the differential carrier between retracted and extended positions, the clutch unit being operable in its released state when the second clutch member is located in its retracted position such that its dog teeth are disengaged from the clutch teeth and further operable in its engaged state when the second clutch member is located in its extended position such that its dog teeth are engaged with the clutch teeth, and wherein the clutch unit further includes a biasing arrangement for normally biasing the second clutch member towards its retracted position.