To provide a rotational position detecting device capable of improving the linearity of output properties of a magnetic sensor in relation to the rotational angle of a rotating body while permitting miniaturization and reduction of costs.
The rotational position detecting device, which is composed of a magnetic sensor 1 and a rotating body 2 having the magnetic field generator 3 and rotating together with an object to be measured, detects a rotational position of the rotating body by using the variation of outputs from the magnetic sensor caused by the direction of the magnetic field generated by the magnetic field generator. An auxiliary magnetic body 5 having such a shape of transverse section that the center is thick, and the thickness becomes thinner toward the both edges, is fixed between the magnetic sensor and the magnetic field generator, near the magnetic sensor, at the straddling positions on the side of the magnetic sensitive surface of the magnetic sensor, and together with the magnetic sensor.
DAIKOKU AKIHIRO
YOSHIZAWA TOSHIYUKI
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