| 摘要 |
PURPOSE:To improve safety for working and reliability for products by changing the material of a winding core from metal to plastic material which is large in thermal expansion coefficients, excellent in mold releasing performance and small in specific gravity. CONSTITUTION:The wound core 11 of a coil body 13 is made from plastic material such as polyplopylene, teflon, acetal resin, etc. which is large in thermal expansion coefficient, excellent in mold releasing performance and small in specific gravity. It may be good to coat resin excellent in mold releasing performanc on polyamide resin, etc. When the coil body 13 is heated preliminarily, thereby, the expanding force of the coil body 13 is acted on its internal side by thermal expansion of the wound coil 11, the coil body 13 becomes higher in dinsity, the voids in the body are decreased and the wound core becomes smaller in weight. So, reliability for the article and safety for the working can be improved and the working processes can be simplified. |
