| 摘要 |
PROBLEM TO BE SOLVED: To provide a spindle motor wherein uneven rotation can be suppressed even if the magnetization strength of an arbitrary pole of a rotor magnet is made different from that of the other pole for the purpose of detecting the rotational position of a disk to be rotatably driven. SOLUTION: The magnetization width of a demagnetized pole 4d is made larger than the magnetization width of the other pole. Further, magnetization widths of next poles 4c and 4e on both sides of the demagnetized pole 4d are uniformly made smaller than the magnetization widths of the other poles. At the same time, the summed magnetization width of the demagnetized pole 4d and the poles 4c and 4e next thereto is made equal to the summed magnetization width of the other three poles. Thus, the time width of the output signal of a Hall element 6 can be made uniform, and irregular rotation can be suppressed. COPYRIGHT: (C)2003,JPO
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