| 摘要 |
PURPOSE:To obtain a position detector with a simple structure and a high detecting accuracy by providing first, second magnetic plates and a magnet plate respectively having N first teeth, N second teeth and N+M magnet teeth and making the opposite positions of the first and second teeth to the magnet teeth agree with each other in positions wherein the polarities of the magnet teeth are reversed. CONSTITUTION:First and second magnetic plates 4 and 5 having N first teeth 4a and N second teeth 5a, respectively, along a circumference, arranged in superposition and having phases shifted by 180 deg., a magnetic sensor 6 provided between the magnetic plates 4 and 5 and a magnet plate 3 opposite thereto and having N+M magnet teeth 3a with 2M magnetized poles are provided. Thus, since the opposite positions of the first teeth 4a and the second teeth 5a to the magnet teeth 3a take positions wherein the polarity of the magnet plate 3 is in reverse, the magnetic polarities of the magnetic plates 4 and 5 are also in reverse and the direction of magnetic flux flowing in the magnetic sensor 6 is inverted by prescribed times in accordance with the amount of the rotational movement of the magnet plate 3 constituting a rotor.
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