| 摘要 |
PROBLEM TO BE SOLVED: To suppress a detection error, even when a structure is adopted, wherein a tangential direction magnetic detection means is arranged between the outer fringe and the inner fringe of a discoid magnet as a view from a rotating shaft direction. SOLUTION: The discoid magnet 2 is provided elliptically as a view from the rotating shaft direction, and a completely-round shaft insertion hole 5 is provided on the rotation center, and further the tangential direction magnetic detection means is always arranged on a middle portion between the outer fringe and the inner fringe of the discoid magnet 2 by a sensor support means 4. Consequently, distortion of lines of magnetic force on a sensor locusαdrawing an ellipse can be suppressed, and the detection error of a rotation angle can be suppressed. Since the detection error can be suppressed, correction of the detection error in a subsequent stage can be abolished or simplified, and reliability can be heightened, and cost can be suppressed. Further, a correction value of each angle is not required to be measured at a shipping time, to thereby shorten an adjustment time and heighten productivity. COPYRIGHT: (C)2009,JPO&INPIT
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