US Patent 7394175 Integral motor and air bearing cooling path

A motor is provided including a housing having single and integral motor and bearing cooling inlets. The motor is arranged within the housing and includes a stator and a rotor assembly supported on air bearings. The cooling inlet is in fluid communication with the motor stator and with the air bearings. The motor cooling inlet provides and the bearing cooling inlet provides a uniform pressure on the rotor assembly. The uniform pressures exerted on the rotor assembly produce bearing loads that generally cancel one another. The source of the cooling flow is uncompressed air at low pressure. This may be achieved by providing a vent in the housing that is common to both the motor cooling inlet and the bearing cooling inlet. As a result, journal bearings and seals of substantially the same size may be used.