| 摘要 |
PROBLEM TO BE SOLVED: To reduce the size of a motor in the radial direction, by so forming its shape that its stator yoke is extended in the axial direction within the spatial scope nearly equal to its fluid bearing, and by making utilizable effectively the space surrounding its fluid bearing. SOLUTION: Paired inner and outer yokes 16A, 16B, constituting a stationary yoke 16, form a magnetic gap in the direction of the rotational shaft of a motor, as their shapes extending in the direction of the rotational shaft. Furthermore, after fastening the stationary yoke 16 together with a circuit board 4 to the caulking portion 5b of a fluid bearing 5, a bobbin coil 17 is inserted into the inner yoke 16A. As a result, by adjusting the number of turns per layer of the bobbin coil 17 and the effective length of the magnetic gap of a molded rotor magnet 20, the design of the motor having various relations of its driving torque to its driving current is made possible. Also, by reducing the size of the motor in the radial direction, and concurrently. by increasing the number of turns of its winding, its necessary driving torque cab be secured without having to increase its driving current. |
