| 摘要 |
PURPOSE:To improve linearity relationship between a magnetic sensor output and an angle of rotation, by sandwiching the magnetic sensor with a closed magnetic path structural body and an annular magnetic member on the same center axis from both side. CONSTITUTION:A closed magnetic path structural body 3 and a magnetic member 7 are fixed non-rotatable while a magnetic sensor 6 therebetween is arranged rotatably on the center axis C with the rotation of an object to be measured fixed on a shaft 4. A magnetic flux is generated within a magnetic member 1 of the structural body 3 turning from N to S pole of a permanent magnet 2 while a leakage magnetic flux is generated inside the member 1 growing weaker as it is separated from the magnet 2. With the existence of the member 7 inside the member 1, the leakage magnetic flux develop large between the members 1 and 7. As a result, there is a substantial change obtained in the magnetic flux following variations in the angle of rotation in an area other than near the magnet 2, indicating 1 to 1 linearity in the relationship between an output of the sensor 6 and the angle of rotation (angle position). Thus, angle position of the sensor is detected accurately from output results of the sensor 6.
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