| 摘要 |
PROBLEM TO BE SOLVED: To provide a structure for fixing a ring magnet in a rotor wherein the relative rotation between a rotor shaft and a ring magnet is inhibited and further degradation in the performance of a rotary machine can be prevented even when breakage or cracking occurs in the ring magnet, and a motor for electric power steering. SOLUTION: According to the structure for fixing a ring magnet, engaging protrusions 22A provided on a rotor shaft 21 and engaging grooves 23A provided in a ring magnet 23 are engaged with each other. Thus, the relative rotation between the rotor shaft 21 and the ring magnet 23 is inhibited. The structure is so constructed that even if breakage or cracking occurs in the ring magnet 23, it occurs in any of the engaging grooves 23A formed between adjacent magnetic poles of the ring magnet 23. Therefore, the breakage or cracking has little or a very little impact on the magnetic flux density distribution of the ring magnet 23, and degradation in the performance of the motor 10 can be prevented. COPYRIGHT: (C)2008,JPO&INPIT
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