Pump motor having fluid cooling system

Abstract

A brushless water pump motor includes a pump housing having an impeller chamber with an impeller disposed therein, and a motor assembly coupled at a first end thereof to the pump housing. The motor assembly includes a stator assembly having laminations and windings, the stator having an interior portion defining a rotor chamber in which a rotor assembly is disposed. There is a partition structure provided between the rotor assembly and the stator assembly for isolating the stator assembly from the rotor chamber, and the partition structure has a wall in communication with the rotor chamber. The pump/motor assembly further includes a hollow shaft in communication with the rotor chamber, such that the rotor assembly and impeller are mounted on the hollow shaft. A bearing structure is operatively associated with the hollow portion of the shaft for supporting the shaft for rotational movement. The pump motor further includes an electronic control unit coupled to a second end of the motor assembly and has an upper surface in communication with the rotor chamber. A fluid flow path structure is arranged to permit fluid to pass from a high pressure portion of the impeller chamber to enter the rotor chamber to submerge the rotor assembly in the fluid and fluid may contact the upper surface of the electronic control unit to cool the electronic control unit. By contacting the wall of the partition structure, the fluid cools the laminations and windings, and by entering the hollow portion of the shaft, the fluid cools the bearing structure.