| 摘要 |
<p>PURPOSE:To make it easy to insert a magnet into a mold and also make it easy to assemble a rotor gear, by providing a resin charging surface of the mold with a conical surface as a guide for the magnet, and allowing part of the conical surface to serve as a path for a molten resin. CONSTITUTION:In case the toroidal magnet is inserted in the mold, then the outer surface of the magnet is covered partly with the resin, and a rotor gear is produced by the insert injection molding method, the mold into which the magnet 3 will be introduced is provided with the conical section 6, which is allowed to serve as the feeding guide for the magnet 3 into the mold. When a plurality of rotor gears 4 are should be molded, the feeding can be considerably improved by the provision of the conical section 6. The conical section 6 also serves to facilitate the throwing of the resin. The outer circumference of the magnet 3 is partly covered with the resin so that the magnet 6 is positioned in place with respect to the rotor gear and the magnet 6 is prevented from being cracked.</p> |
