| 摘要 |
PURPOSE:To make the fixing of a case secure and firm by holding the protecting case, which covers the exposed surface of a permanent magnet, between the flange portion provided around a pole piece and the permanent magnet. CONSTITUTION:An iron cup 2 is fixed to a flange portion 11 of a center piece 1 by rivets 21. Permanents magnets 3 are provided on the inner surface of the iron cup 2, and pole pieces 31 are provided on the inner-diameter side thereof, so that different polarities are alternately formed in the circumferential direction, and are fixed by screws 4. A plastic protecting case 5 has an opening into which the magnetic poles 31 is coupled. The side of the portion held by the permanent magnet 3 and the flange portion of pole piece 31 is the same as the size of difference in levels for holding the pole piece 31, or slightly thinner than said size. Very small convex portions are provided on the portion to be held. In this way, the permanent magnet 3 is inserted into the protecting case 5, and the pole piece 31 is inserted into the opening from the other direction so as to hold the protecting case 5 together with the permanent magnet 3. |
