To dispense with the process of cutting the outside periphery of a rotor iron core by preventing the shrinkage distortion of the outside periphery of the rotor iron core after die-casting of the rotor of a self-starting permanent magnet type of synchronous motor.
In addition to a section where the width of the bridge part A7 between the adjacent permanent magnet burying holes 6 of a rotor iron core 2 is large, this rotor iron core 2 is provided with a wide section so as to raise the strength of the bridge part, thereby removing the distortion of the outside periphery of the rotor iron core 2 after aluminum die-casting. This dispenses with the process of cutting the outside periphery of the rotor iron core, by forming the rotor iron core where electromagnetic steel plates are die-cut in advance and are stacked so that the air gap between it and the inside periphery of the stator iron core may come to specified dimensions.
TAMURA TERUO
YOSHIDA MICHIHIRO
MATSUSHITA REFRIGERATION
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