| 摘要 |
The purpose of the present invention is to enhance the tenacity of an insulator in the main fittings of a spark plug. A spark plug (100) equipped with: an insulator (10) formed in a substantially tubular shape so as to have a through-hole (59) extending along the axial direction (OD), a central electrode (20) being provided at the axial-direction (OD) distal-end side of the through-hole (59); and main fittings (50) formed in a substantially tubular shape, the main fittings (50) having crimped parts (53) on the axial-direction (OD) trailing end, and the crimped parts (53) being crimped to hold the insulator (10) with the insulator (10) inserted therein. The crimped parts (53) are configured such that, in a cross-section along a plane that includes the axis (OL), the distance A between a nearest point (N) that is nearest to the insulator (10) and an intersection point (I) at which a first normal (Lv1) that is perpendicular to the axis (OL) and that passes through the nearest point (N) intersects the outer periphery (532) of the crimped parts (53) is such that A ≥ 1.7 mm, and the wall thickness t of the proximal end (534) of the crimped parts (53) is such that t ≥ 1.20 mm. |
