The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 25, 2018
Filed:
May. 16, 2016
Ngk Spark Plug Co., Ltd., Nagoya-shi, Aichi, JP;
Takehito Kuno, Nagoya, JP;
NGK SPARK PLUG CO., LTD., Aichi, JP;
Abstract
A spark plug includes a tube-shaped metal shell, an insulator having an outer circumference, at least part of which is held by the metal shell, the insulator including an axial hole extending along an axial line, a center electrode disposed in the axial hole, and a ground electrode fixed to the metal shell. The ground electrode includes an outer layer and an inner layer covered with the outer layer, the inner layer having a thermal conductivity higher than a thermal conductivity of the outer layer. A ratio L of L2 to L1 (=L2/L1) falls within a range of 5% to 50% where a width of the inner layer in a width direction of the ground electrode is denoted with L1 and a dimension of an oxide located in an interlayer portion between the outer layer and the inner layer in the width direction is denoted with L2.