| 摘要 |
<p>Yoke plates 3a, 3b of magnetic material rotating in synchronization with a rotary shaft 2 are provided. An axially magnetized magnet 5 is disposed opposite to the yoke plates 3a, 3b through an air gap G1. The outer diameter R1 of the yoke plates 3a, 3b is larger than the outer diameter R2 of the magnet 5. The magnet 5 is fixed to a fixing plate 6 of magnetic material. Hall ICs 9a, 9b are attached to the front ends of the pole pieces 8a, 8b of the fixing plate 6. The Hall ICs 9a, 9b are disposed in a magnetic path M formed by the magnet 5. When the rotary shaft 2 rotates, the opposed areas S1, S2 between the magnet 5 and yoke plates 3a, 3b change, so that the density of magnetic flux passing through the Hall ICs 9a, 9b in the magnetic path M linearly changes in proportion to the rotation angle. The Hall ICs 9a, 9b catch this change and detect the rotation angle of the rotary shaft 2. Thereby, the cost of production of the rotation angle detection device is reduced without deteriorating the detection accuracy.</p> |
