Spark plug for internal combustion engine
AssigneeNgk Spark Plug Co., Ltd.
InventorsMai Nakamura, Akira Suzuki
Life of this patent
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Abstract
A spark plug comprised of an insulator having a stepped portion on an outer circumferential portion thereof, the stepped portion tapering frontward in the direction of the axis of the spark plug, an annular sheet packing and a metallic shell having a taper portion provided on an inner circumferential portion thereof and tapering frontward in the direction of the axis of the spark plug, the metallic shell holding the insulator through a rear end portion thereof being crimped, the stepped portion being seated on the taper portion via the sheet packing, and the taper portion having a groove therein.
Claims9
A spark plug for an internal combustion engine comprising:
- an insulator having an axial hole extending in a direction of an axis and a stepped portion provided on an outer circumferential portion thereof and tapering frontward in the direction of the axis;
- an annular sheet packing;
- and
- a substantially tubular metallic shell having a taper portion provided on an inner circumferential portion thereof and tapering frontward in the direction of the axis, and holding the insulator through a rear end portion thereof being crimped with the stepped portion being seated on the taper portion via the sheet packing;
- the spark plug being characterized in that the taper portion has a groove.
Dependencies are inferred from the claim text.