Patent ID: 8421292
Filing Date: 2013-04-16
Classification: H01F,H02K,Y10T

Abstract:
1. A permanent magnet motor comprising: a rotor; a stator; and a plurality of permanent magnets located on either the rotor or the stator; wherein the permanent magnet is an R—Fe—B based rare-earth sintered magnet including light rare-earth element RL including at least one of Nd and Pr as a rare-earth element R, and partially includes a high coercivity portion in which a heavy rare-earth element RH including at least one element selected from the group consisting of Dy, Ho and Tb is diffused from a selected area of a surface of the permanent magnet in a relatively higher concentration than in other portions, the selected area of the surface of the permanent magnet defining a location of the high coercivity portion of the permanent magnet, the high coercivity portion and a portion other than the high coercivity portion being arranged at the surface of the permanent magnet; and an angle of the permanent magnet formed with respect to a rotation axis of the motor is A°, an angle of the high coercivity portion formed with respect to the rotation axis of the motor is B°, and B°/A° is between more than 0% and not more than 40%.