公开(公告)号：US20180212405A1

公开(公告)日：2018-07-26

申请号：US15565776

申请日：2016-03-28

Applicant: NGK SPARK PLUG CO., LTD.

Inventor： Kentaro KIUCHI ,  Kazuhiko MORI ,  Hironobu MIZUTANI ,  Yuusuke TERANISHI

IPC: H01T13/36 ,  H01T13/02 ,  H01T21/02

CPC classification number: H01T13/36 ,  H01T13/02 ,  H01T21/02

Abstract: A spark plug having a ceramic insulator held by a crimp portion of a metallic shell. The crimp portion satisfies a relation of A≥1.7 mm and a relation of t≥1.20 mm in a cross section of the crimp portion taken along a plane containing the axial line, where A is the distance between a closest point which is a point within the cross section closest to the ceramic insulator and an intersection at which a first orthogonal line passing through the closest point and orthogonal to the axial line intersects with an outer circumference of the crimp portion, and t is a thickness of the proximal end of the crimp portion.