| 摘要 |
PURPOSE:To manufacture a cylindrical multipolar anisotropic magnet with magnetic characteristics by a method wherein multipolar electrostatic field is formed on the surface of a cylindrical cavity in such a manner that north pole and south pole are alternately arranged by arranging a large number of permanent magnets in such a manner that magnetic poles opposing to each other have same polarity and, after that, a mixture is poured in the cylindrical cavity and subjected to anisotropic molding for the predetermined period of time. CONSTITUTION:Permanent magnets are arranged in the periphery of a magnet molding cavity 10 in such a manner that magnetic poles opposing to each other of the permanent magnets adjacent to each other have same polarity. As a result, magnetic poles, the polarities of which are alternately opposite to each other such as N, S and N, appear at the tips of yokes 45a, 45b and 45c. The resultant alternate magnetic poles form multipolar electrostatic field on the surface of the cavity 10. In this case, because each permanent magnet has an arc segment shape, few magnetic flux gathers on a back-up member 7 side and consequently magnetic flux can efficiently be gathered on the molding space 10 side. The mixture of magnetic powder and resin is poured from a nozzle hole 16 in order to be injected through a sprue 18 and runners 20 and 22 into the cylindrical cavity. After being cooled, an anisotropic molded composite magnet is released from a core 8 in order to be recovered by shifting a movable mold 4 downwards and by pushing up a rod 38 by means of the piston of a cylinder so as to raise an ejector pin 34. |
