COMPOSITE BONDED MAGNET AND MANUFACTURING METHOD THEREOF, AND ROTOR OF DC BRUSHLESS MOTOR HAVING CO

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PROBLEM TO BE SOLVED : To solve the problem that in conventional technology, when inserted rare earth permanent magnet is a bonded magnet, the rare earth bonded magnet is subjected twice to thermal hysteresis upon injection molding and further the injection temperature upon the molding of a ferrite-based bonded magnet is as high as about 260-300°C, so that the magnetic characteristics of the rare earth bonded magnet are deteriorated because this magnet is oxidized and deteriorated by the high temperature to reduce the coercive force thereof, etc. SOLUTION : A primary bonded magnet is provided compact containing ferrite or soft magnetic iron content, a secondary bonded magnet compact containing magnetically anisotropic rare earth magnetic substance is disposed inside or outside the primary boded magnet compact, and those two layers are bonded together by fusing thermoplastic resin between them to form a magnetic circuit in a metal mold so that a magnetic field is continuously oriented to insert the primary bonded magnet and to carry out two-stage injection molding. COPYRIGHT : (C)2006, JPO&NCIPI