| 摘要 |
PROBLEM TO BE SOLVED: To provide an inexpensive spark plug for an internal combustion engine, and its manufacturing method, capable of restraining early wear and tear and penetration breakdown of an insulator due to semi-creeping discharge and easily performing a bending process of a creepage grounding electrode. SOLUTION: The spark plug for the internal combustion engine 100 is provided with an insulator 140, a center electrode 120, a main metal fitting 130, and a creepage grounding electrode 110. Out of them, the creepage grounding electrode 110 is provided with a base end part 113 extended from a tip end face 132 of the main metal fitting 130 and so structured to come closer to the center electrode 120 as it gets nearer to the tip end in an axis line C direction of the main metal fitting 130, a tip end face 113 located further toward the tip end in the axis line C direction than a tip end 141b of the insulator 140, and an inner side face 114 forming a semi-creeping gap G2 against the tip part of the insulator 141. COPYRIGHT: (C)2005,JPO&NCIPI
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