PURPOSE: To facilitate manufacture of a motor having high torque and high output by burying a permanent magnet having high coercive force in the groove at the core tooth section of the motor and employing a permanent magnet having low coercive force as the main flux field magnet.
CONSTITUTION: Magnetic rotor steel boards are laminated to produce rotor core blocks 6a, 6b, non magnetized rare earth permanent rod magnets 16a, 16b are inserted into the groove in a rotor tooth 7 and secured in place, then the outer circumference thereof is polished. The permanent rod magnet 16a is magnetized radially and the permanent rod magnet 16b is magnetized in different direction. A non-magnetized Alnico disc permanent magnet is then sandwiched between two rotor cores provided with permanent rod magnets and fixed to a rotary shaft 11 thus assembling a rotor. Thus assembled rotor is then placed in a ceramics and subjected to a magnetic field in the axial direction thus magnetizing the permanent disc magnet.
MORINO ISAMU
NAKATSUKA HARUO
TAKEUCHI IWAO
TOSHIBA CORP