| 摘要 |
PURPOSE:To obtain a thin ringed permanent magnet by a method wherein, when the ringed permanent magnet having a magnetic anisotropy is made in a magnetic field by an extrusion molding method, a tape made of resin-bonded rare earth magnet power is pushed out in a spiral form and after the tape is wound around on a ringed mandrel, the tape is cut in a ringed form along with the mandrel. CONSTITUTION:A hopper 1 is provided on one end of the upper part of a cylinder 2 provided with heaters 3 wound around on its outer periphery, a tapered barrel part 5 is provided on an aperture on the other end of the upper part and a screw 4 is housed in the interior of the cyliner 2. Moreover, a magnetic circuit 6 and a demagnetizing circuit 13, between both of which a cooling die 11 and a water cooling pipe 12 have been held, are provided on the side of the barrel part 5 and magnetic field coils 7 and 8, on which a magnetic line of force 9 generates through a gap 10, are arranged in the interior of the die 11. An extrusion molding device is constituted in such a way and magnet powder is thrown into the cylinder 2 from the hopper 1. The magnet powder is made to pass through the interior of the die 11 by the screw 4, is pushed out from a corrective die 14 being surrounded with a heating heater 15 and is formed into a tape of a spiral form. After that, the tape is wound around on a ringed mandrel and is ringed in a prescribed length along with the mandrel. |
