| 摘要 |
PROBLEM TO BE SOLVED: To attain tendency to grow high efficient by preventing a permanent magnet as high as possible from being demagnetized. SOLUTION: In a through hole 13 formed in the inside of a rotor core 12, when a permanent magnet 16 for forming a magnetic pole is built in, the through hole 13 is constituted in such a manner that both end parts of the permanent magnet 16 are formed with a space part 17 in a manner as positioned within an extension surface extending a surface in an external peripheral side of the rotor core 12 in the permanent magnet 16. Accordingly, the both end parts of the permanent magnet 16 are contiguous to an air layer of low magnetic permeability. Consequently, passing of reverse magnetic flux in the permanent magnet 16 can be extremely prevented. Especially, the length dimension of the space part 17 is set to 20% to 50% the thickness dimension of the permanent magnet 16. COPYRIGHT: (C)2007,JPO&INPIT
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