Coreless-type BLDC motor and method of producing stator assembly having axial vibration attenuation arrangement

摘要

A double rotor-type brushless direct-current motor includes first and second annular-shaped rotors each having a plurality of north and south-polar magnets which are alternately disposed at a predetermined distance; a rotating shaft connected to a central portion of the rotors thorough a bushing; upper and lower cases receiving and rotatably supporting opposite ends of the rotating shaft; an annular-shaped stator having a plurality of stator coils supported by a molding filler to apply electromagnetic force to the first and second rotors in an opposite direction to each other, the stator being mounted between the first and second rotors at a predetermined clearance; and a control printed circuit board for applying a driving current with respect to the stator, the control printed circuit board being mounted one of the upper and lower cases; wherein the upper and lower cases, the control printed circuit board, the first and second rotors have a plurality of ventilating holes for circulating air from the outer side of the motor to the inside of the motor.