| 摘要 |
PROBLEM TO BE SOLVED: To provide a radial anisotropic ring magnet having proper magnetic characteristics through pressure forming. SOLUTION: The method of forming a radial anisotropic ring magnet, having an angle not smaller than 80°and not larger than 100°between the direction of the center axis of a ring magnet and the direction of radial anisotropy given for the magnet as a whole, includes a step of pressure forming a magnetic powder by relatively rotating it, while applying a magnetic field to the magnetic powder from a plurality of direction rather than a direction for forming the magnetic powder filled in the cavity of a metal mould by a horizontal magnetic field vertical forming method. At least a portion of the material of the core of the metal mold used for forming the cylindrical magnet is a ferromagnetic body, having a flux density of not lower than 5 kG. The magnetic powder is rotated from 60 to 120°for the magnetic field direction prior to the rotation of the magnetic powder; while a magnetic field of 0 to 0.5 kOe, generated from a coil, is applied. A magnetic field of not lower than 1/20 and not higher than 1/3 of the magnetic field that is applied prior to rotation is applied, and the magnetic powder is formed, after or during the application of the magnetic field. COPYRIGHT: (C)2008,JPO&INPIT |
