公开(公告)号：US20160218486A1

公开(公告)日：2016-07-28

申请号：US15025609

申请日：2014-08-20

Applicant: NGK SPARK PLUG CO., LTD.

Inventor： Shinya MITSUDA ,  Yuichi YAMADA

IPC: H01T13/20

CPC classification number: H01T13/20 ,  H01T13/38

Abstract: A spark plug includes an insulator having a through hole formed in the direction of an axis, a rod-shaped center electrode inserted in the through hole and extending in the direction of the axis, a metal shell disposed around an outer circumference of the insulator, and a ground electrode electrically conducted with the metal shell and adapted to define a gap between the ground electrode and the center electrode. A front end part of the insulator has a front end surface, an outer circumferential surface and a curved surface region formed between the front end surface and the outer circumferential surface. In a cross section including the axis, a front end of an inner circumferential surface of the metal shell faces the curved surface region in a direction perpendicular to the axis. The curved surface region has a curvature radius of 0.2 mm to 0.8 mm.

Abstract translation: 火花塞包括绝缘体，该绝缘体具有沿轴线方向形成的通孔，插入在该通孔中并在该轴线方向上延伸的棒状中心电极，设置在该绝缘体的外周周围的金属壳， 以及接地电极，与所述金属壳电连接并且适于限定所述接地电极和所述中心电极之间的间隙。 绝缘体的前端部具有形成在前端面和外周面之间的前端面，外周面和曲面区域。 在包括轴线的横截面中，金属壳体的内周面的前端在与轴线垂直的方向上面对弯曲表面区域。 曲面区域的曲率半径为0.2mm〜0.8mm。