| 摘要 |
PURPOSE:To strongly couple a magnet with a boss by composing the boss of a nonmagnetic material of a nonmagnetic rod piece having substantially the same thermal expansion coefficient as the magnet and a die cast material of zinc which fills the space between the magnet coated with the piece and the piece. CONSTITUTION:A cylindrical rod piece 5 of aluminum is formed in the outer diameter slightly smaller than the inner diameter of a cylindrical magnet 1, and a rotational shaft 3 is penetrated through the central portion. The piece 5 is mounted in the magnet 1, zinc is supplied to a space 6 between the magnet 1 and the piece 5 to die cast a boss, thereby completing a rotor. Thus, since the rotor has a small radial size of the zinc die cast part 30 buried between the magnet 1 and the piece 5, the thermal expansion is controlled by the thermal expansion coefficient of the piece 5 and the difference of the thermal expansion from the magnet 1 is suppressed to small value, no gap is formed, and the magnet 1 and the boss are rigidly secured with each other. |
