PERMANENT MAGNET ROTATING MACHINE

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PURPOSE : A permanent magnet rotating machine is provided to improve coercive force of an end portion of a permanent magnet not to easily demagnetize the permanent magnet in a high temperature. CONSTITUTION : A permanent magnet rotating machine includes a rotor(3) and a stator(13). The rotor has a plurality of permanent magnet segments on a side surface of a rotor core(1). The stator has a stator core(11) with a plurality of slots. Both widthwise ends of the permanent magnet segment are thinner than a center part thereof. The permanent magnet segment is a sintered magnetic body a R1-Fe-B composition, wherein R1 is at least one element selected among rare earth elements including Y and Sc. Powder including at least one element selected among oxide of R2, fluoride of R3, and oxyfluoride of R4 is applied on a surface of the magnetic body, wherein each of the R2, R3, and R4 is at least one element selected among rare earth element including Y and SC. The permanent magnet segment is obtained by heat-treating magnetic body and the powder under a vacuum or inert gas condition in a temperature below sintering temperature of the magnetic body. Coercive force at the both widthwise ends of the permanent magnet segment is higher than that of the center part. © KIPO 2008