公开(公告)号：US20210249846A1

公开(公告)日：2021-08-12

申请号：US16973599

申请日：2020-03-19

Applicant: NGK SPARK PLUG CO., LTD.

Inventor： Yusuke TANAHASHI ,  Naoki NISHIO ,  Yusuke KAWASHIMA

IPC: H01T13/34

Abstract: A spark plug including a center electrode that has a large-diameter portion having an outside diameter that is largest in the center electrode. The large-diameter portion is retained at a rear facing surface in an axial hole of an insulator. A metal shell has a diameter increased portion on a rear end side with respect to the center electrode, the diameter increased portion having an inside diameter that is increased toward the rear end side. The insulator has a first portion which is a portion of the insulator in a region from a rear end of the rear facing surface to a front end of the diameter increased portion. The first portion has a thickness that is the largest in the region, and is disposed at least on an outer periphery of the large-diameter portion.