US Patent 7315099 Cooled electric drive unit for a motor vehicle

An electric drive unit for a motor vehicle, comprising:(a) a stub axle;(b) an electric motor having a stator that is fixed with respect to the stub axle and having a rotor that is rotatably supported with respect to the stub axle;(c) a gear system having its input connected to the rotor for torque transmission;(d) a wheel carrier that is rotatably supported with respect to the stub axle and is connected to the output of the gear system for torque transmission;characterized in(e) that air cooling with air circulation is provided for cooling the rotor of the electric motor;(f) and in that the electric motor has provided therein a heat sink for taking up heat from the circulating air.