| 摘要 |
PROBLEM TO BE SOLVED: To improve both the durability of a grounding electrode and the joining strength of a tip to the grounding electrode and firmly prevent exfoliation of a plated layer in association with contact with the tip and the like.SOLUTION: A spark plug 1 includes an insulator 2, a center electrode 5, a main metal fitting 3, a grounding electrode 27, and a grounding electrode-side tip 32 whose one face is joined to the grounding electrode 27 and whose other face forms a spark discharge gap 33 with a tip portion of the center electrode 5. On a surface of the grounding electrode 27, a gap 37 is formed with a portion including a constituting material of the grounding electrode-side tip 32 on the surface where the grounding electrode-side tip 32 is joined, and a plated layer 35 covering a surface other than a region forming the gap 37, of the surface of the grounding electrode 27, is provided. The size A of the gap is 0.01 mm or more and 0.5 mm or less. |
