| 摘要 |
PROBLEM TO BE SOLVED: To provide a glost firing method and a glost firing device for an electrical porcelain for a spark plug, capable of reducing temperature difference of a barrel part and a rear end part of the electrical porcelain heated in glost firing, and to provide a manufacturing method for the spark plug manufactured by the glost firing method. SOLUTION: The electrical porcelain 1, supported by a support member 330 with the barrel part 72 abutted on an edge part of an upper end 331, is heated in a glost firing part 315 of a furnace 310 of an electric furnace 300 by the radiation heat emitted from a heater unit 320 with an arch cross-section provided to its right and left side faces. In the heater unit 320, the degree of curvature is adjusted so that the radiation heat is concentrated near the barrel part 72 of the electrical porcelain 1. Although heat tends to accumulate in a rear end part 73 where heat is conducted, since there is no place for heat to dissipate, the temperature difference between the rear end part 73 and the barrel part 72 can be made small, by intensively heating near the barrel part 72 where the heat can escape to the support member 330. COPYRIGHT: (C)2006,JPO&NCIPI
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