| 摘要 |
PROBLEM TO BE SOLVED: To provide a rotation angle detection device having a linear magnetic flux change to the rotation angle. SOLUTION: This rotation angle detection device is equipped with: a ring magnet connected to a rotating shaft and forming a magnetic field; a ring yoke having a pair of gaps arranged in the magnetic field on the circumferential side of the magnet, forming a magnetic circuit between itself and the magnet, and arranged so that, when a relative angle to the magnet is changed by rotation of the rotating shaft, the magnetic flux density is changed; and a magnetic detector arranged on one of the pair of gaps, for detecting the magnetic flux density. A magnetic flux distribution curve spreading over the whole circumference on the yoke inner circumferential surface has at least one section of flat angle sections F<SB>X</SB>, F<SB>Y</SB>having the approximately constant magnetic flux quantity, and has a characteristic wherein the section length of an N-pole side angle section X which is an N-pole side part of the magnetic flux distribution curve is different from the section length of an S-pole side angle section Y which is an S-pole side part of the magnetic flux distribution curve. COPYRIGHT: (C)2005,JPO&NCIPI
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