| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a magnet reducing a magnetic flux density fluctuation that a sensor detects, with respect to a cavity distance fluctuation between a magnetized magnet and a sensor detecting the magnetic flux density of the magnet, and magnetization means therefor.SOLUTION: So-called surface magnetization for dividing and magnetizing a surface is applied to a magnet, and a sensor is disposed on the magnetized surface. Magnetization formed from an area (a) which is magnetized in a narrow pitch and an area (b) which is magnetized over a wider area is applied to the magnet. When a sensor having sensitivity in a parallel direction with respect to the magnetized surface is disposed right on the magnetized surface of the magnet, at a side where a cavity between the magnet and the sensor is narrow, a magnetic flux (c) in the narrow magnetized area is dominant and the sensor detects the magnetic flux density. At a side where the cavity is wide, on the other hand, a magnetic flux (d) is dominant and the sensor detects a magnetic flux density in a direction inverse to the magnetic flux (c). As a result, in a cavity area where the magnetic flux (c) and the magnetic flux (d) are interfered with each other, the magnetic flux density change to be detected by the sensor becomes moderate and the magnetic flux density change with the cavity distance fluctuation is reduced.</p> |
