Patent ID: 6708388
Filing Date: 2004-03-23
Classification: H01F,H02K,Y10S,Y10T

Abstract:
A method of making a permanent magnet field compact DC motor, the method comprising:fixing a pair of rare earth magnets composed of rare earth-iron based rapidly quenched and solidified flakes to a soft magnetic frame, so that the pair of rare earth magnets extend along an inner peripheral surface of said soft magnetic frame, and unsaturation-magnetizing the rare earth magnets so that demagnetization curves at circumferentially opposite end portions of the rare earth magnets are made smaller than a demagnetization curve at a central portion of a magnetic pole of each of the rare earth magnets, wherein the soft magnetic frame has portions that do not serve as a back yoke at outer peripheral surfaces of the circumferentially opposite end portions of the rare earth magnets, and the rare earth magnets are unsaturation-magnetized with a soft magnetic material having a round or oval section interposed therebetween.