| 摘要 |
PURPOSE:To strengthen the driving and detecting magnetism of a cylindrical magnet and to facilitate the manufacture of the magnet by magnetizing a driving pole at the outer periphery of the cylindrical part radially in anisotropy and magnetizing a detecting pole at the of isotropy. CONSTITUTION:A driving pole is magnetized radially in anisotropy at the outer periphery of the cylindrical part of a sintered cylindrical magnet 4 made of magnetic powder. The one end or both ends B of the cylindrical part are formed in isotropy, and the end C is magnetized in vertical direction to the radial pole as a detecting pole. Magnetic powder is supplied between a die 11 and a core 12 made of magnetic material, is pressed by upper and lower punches 14, 17, and is compression molded in the radial field. Nonmagnetic material 26 is disposed in the vicinity of one or both ends of the hole of the die of this case, thereby providing anisotropy to the molded product, and one or both ends are formed in isotropy. |
