To prevent angle errors due to center deviation while adopting a columnar permanent magnet in a rotation angle detection sensor.
The rotation angle detection sensor includes: regarding the columnar permanent magnet 1 as an anisotropic magnet magnetized on both face four poles in an axial direction for a columnar molding having magnetic anisotropy in the axial direction; arranging a plurality of magnetic sensors 2, 3 arranged on the same circumference at a position separated in the axial direction from one end face of the permanent magnet 1 in a radial region A of 55-80% of a permanent magnet radius from a center of the concentricity of the permanent magnet 1; and being detected with the plurality of the magnetic sensors 2, 3 in a region having loose change of magnetic flux density distribution of the axial direction by providing an interval g of 1.5-3 mm between the plurality of the magnetic sensors 2, 3 and one end face of the permanent magnet 1 in the axial direction.
Takayoshi Tagawa
Higashio Masahiro
Tounaga Mitsuhiro
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