| 摘要 |
PURPOSE:To obtain a construction wherein no magnetic powder is exposed on the surface of a magnet and to give it a function to be substituted for a brass case, by making a permanent magnet of synthetic resin having magnetic powder, by forming a ferromagnetic member integrally with the permanent magnet made of synthetic resin, and by preventing the magnetic powder from being exposed on the surface of the permanent magnet. CONSTITUTION:A permanent magnet 1 has a hole 1a provided between a magnetic pole surface (a) and a magnetic pole surface (b), and a ferromagnetic member 2 is incorporated into and formed integrally with the magnetic pole surface (a) simultaneously when the permanent magnet 1 is injection-molded. On the other magnetic pole surface (b) of the permanent magnet 1, a ferromagnetic member 3 is attracted removably, and a ferromagnetic projection 3a of the ferromagnetic member 3 and a projection 2a of the ferromagnetic member 2 are in contact with each other inside the hole 1a of the permanent magnet 1 so that a closed circuit of magnetism is formed by the permanent magnet 1, a ferromagnetic plate 2b, the projection 2a, the projection 3a and a ferromagnetic plate 3b. The permanent magnet 1 is made of synthetic resin containing magnetic powder (m), and the surface thereof is covered with a resin material (p) (in the form of a resin-skin layer, in particular) and moreover is formed to be a fine and smooth plane. The permanent magnet 1 to be employed as a fitting for engagement needs to have a skin film (s) of plating, coating or the like. |
