| 摘要 |
PROBLEM TO BE SOLVED: To provide a DC motor in which friction torque generated by core loss (compression stress) can be reduced and the ripple of the friction torque is minimized. SOLUTION: The DC motor 1 is configured such that a magnet 3 is attached to the internal peripheral surface 2a of a yoke 2, an armature core 5 laminated of a plurality of electromagnetic steel sheets is arranged inside the magnet 3 so as to oppose the inside thereof in a non-contact state with the magnet, an armature shaft 7 with a plurality of projections 8 formed at the periphery of the shaft at equal intervals is press-fitted and fixed to a round hole 5a at the center of the armature core 5, and the armature core 7 is rotatably supported to the yoke 2. When the number of the projections of the armature 7 is set as Np, a natural number is set as (n), the number of teeth of the armature core 5 is set as S, and the greatest common divisor of the number of the teeth S and the natural number Ns of the number of coverings of the teeth 5b of the armature core 5 relative to an angleθbetween edges of the magnet 3 is set as Ng; the number of the projections formed at the armature shaft 7 is set as a number that is obtained from a formula; Np = n x S/Ng. COPYRIGHT: (C)2004,JPO
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