| 摘要 |
PURPOSE:To reduce the size and cost of processing by introducing a rare-earth group cobalt system resin bonded magnet as a permanent magnet rotor of a motor. CONSTITUTION:An upper magnetic circuit 25, an upper coil 26, an upper punch 14 and an upper core 27 are ascended by an upper cylinder 16 and a space 13 is filled with a mixture of rare-earth magnetic powder and plastic binder. Then, while a current is applied to coils 26, 20 which generate attractive magnetic field each other, the punch 14 is descended to compress the mixture and an end surface C which is made anisotropic in parallel to the axial direction is formed. This surface portion becomes a speed detection magent. Then, a die is opened by the cylinder 16 and the space 13 is again filled with the mixture and after the space 13 is closed up by the punch 14, while a radial magnetic field is applied by the coils 26, 20 which are connected so as to generate a repulsive magnetic field each other, the mixture is compressed. With this constitution, a cylindrical part 4 which is made anisotropic along the radial direction can be formed. |
