| 摘要 |
PROBLEM TO BE SOLVED: To provide a spark plug for internal combustion engines, which is effective in prevention of a side lifted flame, generates normal spark discharge, and has good ignition nature of fuel-air mixture further. SOLUTION: The spark plug 10 for internal combustion engines equips with a main metallic component 13, to which a screw part 13b of a bearing number of M12 is formed, in its outside surface. The main metallic component 13 has an annular chamfered part 13c of C0.1 covering from the tip side end face 13d to the tip side inner side face 13e. Further, the spark plug for internal combustion engines of the embodiment 1 is made to have a projection size F in its diameter direction of welding-drop part 14b of 0.1 mm or less.
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