| 摘要 |
PROBLEM TO BE SOLVED: To improve linearity of output by a simple structure in a noncontact type rotation angle detection sensor using a Hall element. SOLUTION: The outer circumferential surface of a ring permanent magnet 15 fixed to a rotor 10 and having two poles of N and S in the radial direction is surrounded by a fixed side yoke 20 at a fixed interval. The fixed side yoke comprises the first and second outside yokes 30, 40 piled in the axial direction, and the Hall element 25 is arranged in a gap 32 of the first outside yoke. The height h3 in the axial direction of the first outside yoke is changed along the circumferential direction, and the height h4 of the second outside yoke has a complementary relation to the height h3 of the first outside yoke, and the first and second outside yokes 30, 40 are piled at a fixed interval Lh. The ratio between the quantity of a magnetic flux passing the gap and the quantity of a magnetic flux not passing the gap is changed corresponding to rotation of the ring permanent magnet 15, and additionally the magnetic flux quantity itself flowing in the first outside yoke is changed by the height change, and linearity of the output from the Hall element can be improved. COPYRIGHT: (C)2006,JPO&NCIPI
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