| 摘要 |
PURPOSE:To allow an annular magnet to be simply configurated and manufactured at low cost by making molten plastic mixed with magnetic powder pass through an annular passage continuously and making a magnetic line of force pass through the molten plastic in the radial direction via members forming inner and outer periphery surfaces of the passage, thereby magnetizing the magnetic powder and giving orientation to the magnetic powder. CONSTITUTION:Material obtained by mixing plastic and magnetic powder at the fixed rate is supplied to a cylinder 10 from a hopper 14, made to melt while it is transferred, sent out and supplied to a passage 40 of a die 4 through a hole 20 of a non-magnetic cylinder member 2 continuously. Simultaneously, a solenoid 9 is energized to generate a magnetic line of force 19, generate a magnetic field in the molten material passing through the passage 40, to magnetize the magnetic powder and give orientation to the magnetic powder. A cylindrical magnet 30 is continuously pushed out from the die 4, cooled by a proper cooling device and solidified. This cylindrical magnet 30 is magnetized in the radial direction. Accordingly, this magnet is cut by a proper cutting device to form an annular magnet of the fixed dimension. |
