公开(公告)号：US20170256917A1

公开(公告)日：2017-09-07

申请号：US15507893

申请日：2015-07-23

Applicant: NGK SPARK PLUG CO., LTD.

Inventor： Kengo FUJIMURA ,  Toshitaka HONDA ,  Hirokazu KURONO ,  Ryuji NAGAE

IPC: H01T13/38 ,  H01B3/12 ,  H01T13/32 ,  H01B17/58

CPC classification number: H01T13/38 ,  H01B3/12 ,  H01B17/56 ,  H01B17/58 ,  H01T13/20 ,  H01T13/32 ,  H01T21/02

Abstract: An insulator is rendered less breakable. A spark plug insulator is a tube-shaped spark plug insulator having a through hole extending in a direction of an axial line. The spark plug insulator contains alumina as a main component and mullite at at least part of the insulator. Mullite is contained in only an inner circumferential surface of the tube-shaped spark plug insulator and in at least part of the inner circumferential surface of the spark plug insulator in an area extending toward a distal end from a portion having a largest outer diameter.