| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a cord-like heating wire being economically excellent, capable of obtaining stable a temperature control signal and an overheat prevention signal by providing a circuit in which a temperature detecting element wire and an overheat detecting element wire having no insulating cover are wound alternately around a polymer heat sensitive layer in spiral at a constant interval, to separate a temperature control signal from an overheat protection signal even if DC voltage and AC voltage are applied in convolution. <P>SOLUTION: A heating element wire 2 is wound around a core 1 in spiral. A polymer heat sensitive layer 3 is formed around it, an overheat detection element wire 5 and a temperature detection element wire 4 are alternately wound around the outer periphery in spiral at a constant pitch interval. Further an insulation coating layer 6 is formed over it. When an electric signal of the overheat detection element wire 5 is subtracted from an electric signal coming from the temperature detection element wire 4, a temperature control signal, with an AC impedance being eliminated, is calculated. Thus, temperature control by the temperature detection element wire 4 and overheat prevention control by the overheat detection element wire 5 are performed with high precision. <P>COPYRIGHT: (C)2013,JPO&INPIT |
