| 摘要 |
PURPOSE:To increase the leakage magnetic field intensity, and to improve the linearity of an output characteristic by placing concentrically two pieces of circular rings consisting of a magnetic material, and forming a closed magnetic circuit by providing a permanent magnet on a bisected position of each circular ring. CONSTITUTION:A circular ring 10 of the outside and a circular ring 11 of the inside are both formed by using pure iron. As for permanent magnets 12, 13 for connecting both circular rings 10, 11, Alnico whose temperature characteristic is excellent is used. Also, as for a magnetic detecting element, a barber pole type magneto-resistance element is used, by which a rotational angle sensor 15 is formed. At the time of a state that the sensor 15 has rotated a little against the element 14, a closed magnetic circuit 16 indicated with an arrow is formed in the circular ring 10 and the circular ring 11, and also, a leakage magnetic field 17 is formed extending from the circular ring 11 to the circular ring 10. In the element 14, an electromotive force is generated by the leakage magnetic field 17.
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