| 摘要 |
PURPOSE:To unnecessitate the use of a permanent magnet as another part, by uniting a spool with resin with a mixture of magnetic powder and providing a function of a permanent magnet consisting a part of a magnetic circuit in the spool. CONSTITUTION:A spool 10 is formed by uniting resin with a mixture of magnetic powder around an iron core 11. After an exciting coil 12 is wound around the spoo 10, a stronger magntic field than a saturated magnetic field of the iron core 11, and the spool 10 is magnetized in N and S poles. A movable iron piece 13 is installed on the side of the iron core 11, and a recovery spring 14 is provided to make an electromagnet. Magnetic flux phi1 produced at the iron core 11 is shortcircuited through the iron core 11, and does not pass the movable iron piece 13. The movable iron piece 13 is not influenced by the magnetic flux phi1. |
