Differential unit

A differential unit comprising:

• a housing;
• a drivable differential carrier supported in the housing for rotation about an axis;
• p1 two output elements rotatable about said axis relative to the differential carrier and connected to respective output shafts;
• differential gears rotatably supported by the differential carrier and having driving connection with the output elements to permit differential rotation thereof;
• a friction assembly axially supported by one rotatable element of the differential, and axially loadable by an actuating means to cause a frictional restriction of said differential rotation of the output elements;
• the actuating means comprising an abutment ring axially fixed relative to the housing;
• an actuating ring movable relative thereto, one of the abutment and actuating rings being movable angularly relative to the other;
• means for producing an axial movement of the actuating ring upon said relative angular movement between the rings, said means comprising cooperating surfaces provided on said abutment ring and actuating ring, and rolling members disposed therebetween;
• wherein the cooperating surfaces provided on the abutment ring and actuating ring, and the rolling members disposed therebetween, are designed such that no self-inhibition of relative movement occurs therebetween;
• and
• further comprising an electric motor and a reduction gearing for effecting said angular movement of said one of the abutment and actuating rings, the differential unit being of a planetary type comprising differential gears supported for rotation about axes parallel to said differential carrier axis, the axial thrust exerted by the actuating means being transmitted at least through hollow journals of planetary wheels and into the friction assembly, the friction assembly being connected directly between the output elements of the differential unit.