| 摘要 |
PURPOSE:To prevent the boundary portion between a wide terminal portion and a heating portion from being disconnected, by decreasing the resistance value of the boundary portion in its longitudinal direction sequentially with the approach to the terminal portion, or covering the surface of the boundary portion with a vitreous protective film. CONSTITUTION:A boundary portion 22 is widened sequentially with the approach to a terminal portion 23, and an electric heating body 2 at this boundary portion decreases in electric resistance in its longitudinal direction with the approach to the terminal portion 23. Accordingly, the temperature gradient of the boundary portion 22 is eased. Or an attempt is made to ease the temperature gradient of the boundary portion 22 by covering the surface of the boundary portion 22 with a vitreous protective film 3 and letting heat generated in the end portion of a heating portion 21 escape to the terminal portion 23 via the protective film 3. In consequence of this structure, a heating body can be obtained with the low incidence of disconnection even in case of being put to repeated working use in its large power output condition. |
