| 摘要 |
PROBLEM TO BE SOLVED: To reduce cogging torque of a DC brushless motor with a rotor comprising permanent magnet which is magnetized with N-poles and S-poles alternately in the circumferential direction. SOLUTION: In the DC brushless motor, comprising a stator 22 which is disposed with a stator yoke 25 comprising a plurality of core slots 26 on which coils 27 are wound, respectively; and a rotor 23, which has magnets 28, which are disposed rotatably facing the stator 22, and on which N-poles and S-poles are alternately magnetized in the circumferential direction, when an interval between the maximum value PH and the minimum value PL of magnetic flux density, which makes a boundary position P0 between the N-pole and the S-pole the center, is T1 , and a magnetizing period for a pair of N-pole and S-pole is T0 , magnetization distribution of magnets 28 is set so that a ratio (T1 /T0 ) between the interval T1 and the magnetizing period T0 becomes 1/3 to 1/2.
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