| 摘要 |
While gastightness is improved through increase in crimping force, deformation of a sheet packing associated with increase in crimping force is restrained, and in turn, breakage of an insulator is more reliably prevented. A spark plug 1 includes an insulator 2 having a stepped portion 14 provided on an outer circumferential portion thereof and tapering frontward in the direction of the axis CL1; an annular sheet packing 22; and a metallic shell 2 having a taper portion 21 provided on an inner circumferential portion thereof and tapering frontward in the direction of the axis CL1, and holding the insulator 2 through a rear end portion thereof being crimped with the stepped portion 14 being seated on the taper portion 21 via the sheet packing 22. The taper portion 21 has a groove 40. Thus, a portion of the sheet packing 22 which, in the case of the taper portion 21 being flat, would spread radially outward or inward can at least partially bulge into the groove 40. |
