| 摘要 |
PURPOSE:To lighten an apparatus by making a magnetic circuit of a necessary minimum electromagnetic steel sheet and a circuit outer periphery of a lightweight insulating base material. CONSTITUTION:A capstan motor is formed by a rotor 5 composed of an annular permanent magnet 1, a yoke 2 fitted to said permanent magnet and a boss 3 fastening a rotating shaft 4 and by a stator 6 composed of an electromagnetic steel sheet 7 becoming a part of magnetic path and an insulating layer 8 covering the top face of said steel sheet. Also, an armature 10 radially formed by a plurality of coils 10a is fastened to the top surface of the stator 6. In this case, an outer diameter of yoke 13 is caused to correspond with that of the permanent magnet 1, a detent projection 13a is formed in the outer peripheral portion of said yoke and an insulating base material 14 is fitted to the outer peripheral portion of the yoke 13. Further, stepped portions 13b, 14b are formed in the fitting portion of both the yoke and base material. Thus, this apparatus is lightened, because the magnetic circuit is formed by a necessary minimum electromagnetic steel sheet 7.
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