| 摘要 |
<p>PURPOSE:To detect with a high resolution an absolute rotational position extending over the whole periphery of one rotation, by providing two kinds of patterns on a rotor part. CONSTITUTION:In accordance with an opposed area of a good conductor rectangular piece 3a of a rotor part 3 to be end part of each phase pole part of a detecting head 1, an eddy current flows to its part, and a magneto-resistance variation caused by this eddy current loss occurs in a magnetic circuit of pole parts 1A-1D. In accordance with a value of this magneto-resistance, a relative rotational position of the rotor part 3 to the head 1 is detected by an absolute value within an angle range of one pitch of the first pattern. Subsequently, when a magnetic flux of pole parts 2A-2D of a detecting head 2 passes through a part of a spiral wire 3b, an eddy current flows, and by a magneto-resistance value corresponding to its current, a rotational position of the rotor part 3 to the head 2 is detected by an absolute value within a range of one cycle of a variation of the second pattern. By combining these first and second rotational position detecting data, an absolute rotational position detecting data of a high resolution can be obtained extending over a wide range by a vernier theory.</p> |
