| 摘要 |
PURPOSE:To obtain an anisotropic permanent magnet without decrasing the extrusion capacity by a method wherein, when the resin-bonded rare earth permanent magnet made of a mixture, wherein a thermoplastic resin has been used as a bonding material, is extrusion-molded, draw-out units which synchronize with the extrusion rate, are provided at the point of the molding metal mold of the extrusion molding device. CONSTITUTION:A mixture of 65vol% of magnet powder of a rare earth intermetallic compound, whose particle size is 2-80mum, and 35vol% of nylon, which is a thermoplastic resin, is thrown in a cylinder 2 built-in with a screw 4 through a hopper 1. The mixture is mixed by the screw 4 while being heated by heaters 3 provided on the outer periphery of the cylinder 2 at about 300 deg.C and is pushed out to a tapered barrel part 5 by the turning force of the screw 4. After that, the mixture is made to pass through a magnetic circuit part 6 combined with a molding die, is made to orientate by a magnetic field, and then is cooled in a cooling part 7. After this, the mixture is made to pass through a demagnetizing circuit 8 and is pushed out after being subjected to a demagnetization. Moreover, draw-out rollers 9 with the surfaces coated with rubber are provided on the rear stage of the circuit 8 in this extrustion molding device constituted in such a way and a desired extrusion molded product 10 is obtained by making the rotation of the rolllers 9 synchronize with the extrusion rate. |
