US Patent 7759828 Integrated electric motor driven compressor

A motor driven compressor assembly includes a motor housing having a fluid inlet and a fluid outlet. A motor is disposed within the motor housing and includes a rotor that is coupled to a rotatable shaft and a stator. Several passages fluidly connect the fluid inlet and the fluid outlet. One passage is located radially outward of the stator and another passage extends through the rotatable shaft. A compressor is in fluid communication with the fluid outlet of the motor housing. Operation of the compressor produces a fluid stream through the motor housing. The fluid stream transfers heat away from the motor to cool the motor.