| 摘要 |
PURPOSE:To improve the productivity of a high quality anisotropic magnet, by extruding and forming a mixed material wherein a mixing medium and an additive are added to oxide magnetic powder as required at the specified portion of the magnetic poles of a cylindrical permanent magnet, and, therafter, performing sintering. CONSTITUTION:A mixed material comprising 100pts.wt. of Sr ferrite particles whose average diameter is about 1mu, 1pt.wt. of CaO, 1pt.wt. of SiO2, 15-25pts.wt. of water, and 1pt. of CMC (carboxylmethylcellulose) is charged into a hopper 6 of an extruding machine, mixed and compressed with a mixing screw 7, and the slurry is cut with a shredder 8. In this case, the air is evacuated by a vacuum pump 9 through a vaccum pipe 10. Then, the slurry is extruded by an extruding screw 11 through a tapered barrel 12, and a metal mold 13. The formed body is cut into a specified length at the outlet of the metal mold 13. Then, sintering is performed, and a development pole is obtained as a magnetic body to be fixed around a shaft 2. Only the portion of a magnetic pole N1 is made to be an anisotropic ferrite magnet 4, and the other portion is made to be an isotropic ferrite magnet 5. |
