| 摘要 |
<p>PURPOSE:To prolong the service life of a tip cartridge of the electric soldering iron using induction coils by forming a coil wire of a lower layer consisting of a mixture mainly composed of a silicone resin and fine inorg. powder and an upper layer consisting of an arom. polyimide resin and specifying the film thickness ratio of the lower layer/the upper layer. CONSTITUTION:The coil wires 3 of the induction coils 4 are composed of the double coated wires formed by using the mixture mainly composed of the silicone resin, such as ordinary methyl silicone, and the inorg. powder, such as alumina, as the lower layer and the arom. polyimide resin, such as arom. tetracarboxylic dianhydride, as the upper layer and specifying the film thickness ratio of the lower layer/the upper layer to a 1/6 to 6/1 range. The heat resistance of the insulating films of the coil wires 3 is improved even if the heater 5 formed by using copper as the inside layer winding an alloy magnetic material around this inner layer is heated to a high temp. of the Curie temp. of the alloy magnetic material by passing a high-frequency current to the induction coils 4. The layer shorting between the induction coils 4 or the dielectric breakdown between the induction coils 4 and heater 5 is prevented.</p> |
