| 摘要 |
PURPOSE:To improve driving torque so that the space may be narrowed between a driving magnetic pole and a revolution-detecting magnetic pole. CONSTITUTION:A peripheral region 4a of an end face 4 is close to an exciting coil 11 and is formed into the shape corresponding to the coil form of an exciting coil 11. Consequently, an exciting coil 10 is wound up at a groove in circumference 8 so that it may creep under an exciting coil 11. With this magnetizing device, when an exciting coils 10 and 11 are excited, 8-poled driving magnetic pole and 120-poled revolution-detecting magnetic pole are magnetized to an end face of disk magnet, respectively. Besides, as there is no gap between exciting coils 10 and 11, it is possible to remove the non-magnetized portion so far come about. The space between the driving magnetic pole and revolution- detecting pole can therefore be narrowed. The driving magnetic pole can be formed in the wide parts of the magnet end face and the improvement of the driving torque be achieved.
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