US Patent 9331552 Rotor assembly with heat pipe cooling system

An electric motor cooling system is provided in which at least one heat pipe is captured within at least one hollow region within the motor's rotor shaft. An end of the heat pipe that extends out and away from the end of the rotor shaft is coupled to a heat exchanger, for example a heat sink in which the fins of the heat sink are shaped as fan blades. During motor operation, as the rotor heats up thermal energy is absorbed by the heat pipe within the rotor shaft and transferred to the heat sink for efficient removal.