Use of an involute shaped housing surrounding shaft(s) to promote shaft annulus fluid flow

摘要

The powertrain includes a sump and an electric motor-generator configured to convert electrical energy into mechanical energy. The electric motor-generator includes a stator and a rotor. The rotor includes a rotor shaft and is configured to rotate about a shaft axis relative to the stator. The powertrain further includes an output shaft rotatable about the shaft axis and extending through the rotor shaft along the shaft axis. The output shaft and the rotor shaft jointly define a substantially annular gap therebetween. The electric motor-generator also includes a motor housing covering the stator and the rotor. The motor housing defines a housing passageway in fluid communication with the sump and the substantially annular gap. The housing passageway includes a substantially involute shaped portion in order to facilitate flow of the cooling fluid from the sump to the substantially annular gap.