| 摘要 |
PROBLEM TO BE SOLVED: To provide a stepping motor intended to reduce noise which is produced when the motor is driven and enhance the accuracy of rotational angle. SOLUTION: A cylindrical magnet 2 is fixed on a shaft 1 to form a rotor. A pair of bobbins 4A and 4B in phase A and phase B with coils 6A and 6B wound on them are placed on both sides of the rotor in the axial direction. Yokes 8A, 8B, 10A, and 10B which make pole teeth are fixed at both the ends of the bobbins, opposite to the circumferential surface of the magnet 2. With axial deflection produced in the position of the magnet 2, a difference is made between the clearance between the yokes in either phase and the magnet in the axial direction and the clearance between the yokes in the opposite phase and the magnet in the axial direction. Thus, magnetic attractive force in the axial direction is produced between the yokes and the magnet with the smaller clearance. A notch 11 in the circumferential direction is formed in the center portion of the magnet 2. Thus, the area of opposition between the magnet 2 and the pole teeth is kept constant against deflection of the rotor in the axial direction. COPYRIGHT: (C)2004,JPO
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