公开(公告)号：US20210257816A1

公开(公告)日：2021-08-19

申请号：US17275054

申请日：2020-06-23

Applicant: NGK SPARK PLUG CO., LTD.

Inventor： Hiroki SHIMADA ,  Haruki YOSHIDA ,  Naoya HARATA

IPC: H01T13/20 ,  H01T21/02

Abstract: An insulator for a spark plug including a first portion; a second portion located on the rear side of the first portion, an outer diameter F at a front end of the second portion being smaller than an outer diameter of the first portion; a third portion located on the front side of the first portion, an outer diameter D at a rear end of the third portion being smaller than the outer diameter of the first portion and the outer diameter F at the front end of the second portion; a first slope portion connecting the first portion and the second portion; and a second slope portion connecting the first portion and the third portion. A length A of the second slope portion and a length B of the first slope portion satisfy 2.0≤A/B≤3.9, and 0.50≤D/F≤0.88 is satisfied.

公开(公告)号：US20230008031A1

公开(公告)日：2023-01-12

申请号：US17911859

申请日：2021-01-18

Applicant: NGK SPARK PLUG CO., LTD.

Inventor： Hiroki SHIMADA ,  Haruki YOSHIDA ,  Shota TAKAENOKI

IPC: H01T13/36 ,  H01T13/20

Abstract: A spark plug which includes an insulator having an axial hole extending along an axial line, a metallic shell disposed around the insulator, and a center electrode disposed in the axial hole to be located on the forward end side of the axial line is provided. The insulator has a step portion provided on the outer circumferential surface thereof and facing toward the forward end side. The metallic shell has a receiving surface provided on the inner circumferential surface thereof and facing toward the rear end side and with which the step portion is engaged via a packing. A portion of the step portion on the outer circumferential side is a first curved surface being convex toward the forward end side, and a portion of the step portion on the inner circumferential side of the first curved surface is a second curved surface which being convex toward the rear end side.

公开(公告)号：US20190312415A1

公开(公告)日：2019-10-10

申请号：US16373707

申请日：2019-04-03

Applicant: NGK SPARK PLUG CO., LTD.

Inventor： Hiroki SHIMADA

IPC: H01T13/36 ,  H01B17/58

Abstract: A spark plug having a metal shell and an insulator, wherein a stepped portion that includes a rear-end-side facing surface that retains an insulator either directly or via another member is provided at an inner periphery of a metal shell. The stepped portion includes a first convex portion that includes the rear-end-side facing surface, a second convex portion that is disposed on a front end side of the first convex portion and that is adjacent to the first convex portion, and a connection portion that connects the first convex portion and the second convex portion to each other.