| 摘要 |
PROBLEM TO BE SOLVED: To more surely prevent a chip from being peeled off and cracked by effectively reducing stress difference generated between the chip and an annular part.SOLUTION: A spark plug 1 includes: an insulator 2 having an axial bore 4; a center electrode 3 inserted in the axial bore 4; a main body metal filling 3 provided in the outer periphery of the insulator 2; a ground electrode 27 which has an annular part 27A having the center electrode 5 arranged in the inner periphery at the tip itself and in which a base end part itself is fixed to the main body metal fitting 3; and an annular chip 32 which is joined to the inner periphery of the annular part 27A and forms a spark discharge clearance 28 between the inner peripheral surface itself and the center electrode 5. A recess 35 is provided in at least one of the inner periphery and the outer periphery of the annual part 27A. |
