Title:
SPARK PLUG
Document Type and Number:
WIPO Patent Application WO/2021/106243
Kind Code:
A1
Abstract:
Provided is a spark plug that is capable of improving fouling resistance. The spark plug comprises a cylindrical insulator, a central electrode disposed in an axial hole in the insulator, and a cylindrical main metal fitting disposed at an outer periphery of the insulator. A shoulder of the main metal fitting comprises a distal-end-facing surface that faces a distal end side, a rear-end-facing surface that faces a rear end side, and a connecting surface that connects the rear-end-facing surface and the distal-end-facing surface. The rear-end-facing surface locks into place with a stepped section of the insulator. The main metal fitting comprises a distal cylindrical section that links to the distal end side of the shoulder. An inner circumferential surface of the distal cylindrical section links to the distal-end-facing surface of the shoulder via a C surface or an R surface, and a corner, at which the connecting surface and the distal-end-facing surface are linked, is positioned to the distal end side of the distal end of the insulator.
Inventors:
TSUGA SHUNSUKE (JP)
OZEKI KEIJI (JP)
OZEKI KEIJI (JP)
Application Number:
PCT/JP2020/017969
Publication Date:
June 03, 2021
Filing Date:
April 27, 2020
Export Citation:
Assignee:
NGK SPARK PLUG CO (JP)
International Classes:
H01T13/20; H01T13/32; H01T13/54
Foreign References:
| JP2013503447A | 2013-01-31 | |||
| JPS5553895U | 1980-04-11 |
Attorney, Agent or Firm:
PATENT FIRM SHINMEI CENTURY (JP)
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