Patent ID: 6570288
Filing Date: 2003-05-27
Classification: H02K

Abstract:
An outer rotor type brushless direct current motor, comprising:a stator fixed so as to surround an outer periphery of a rotating shaft; and an outer rotor arranged so as to surround the outer periphery of the stator and to rotate around the rotating shaft, wherein the outer rotor is formed from an annular yoke and a plurality of permanent magnets attached along the inner periphery of the yoke, each said permanent magnet having an N magnetic pole and an S magnetic pole on either end and oriented in a circumferential direction such that the N magnetic pole of each permanent magnet faces the S magnetic pole of an adjacent one of said permanent magnets, and wherein the radially outer periphery of the two end sections in the circumferential direction of each of the permanent magnets has a thickness less than a center section of the permanent magnet so as to form thin sections, and magnetic flux passage sections of the yoke providing connection between the thin sections of adjacent permanent magnets have a thickness greater than sections of the yoke adjacent center sections of said permanent magnets.