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:
Nov. 04, 2014
Filed:
Feb. 09, 2012
Daisuke Sumoyama, Nagoya, JP;
Tomoo Tanaka, Kitanagoya, JP;
Tsutomu Shibata, Owariasahi, JP;
NGK Spark Plug Co., Ltd., Aichi, JP;
Abstract
A spark plug having an insulator that can be restrained from cracking in an environment of heating and cooling cycles. The spark plug includes an insulator having an axial bore extending in the direction of the axis, and a center electrode held in one end portion of the axial bore. The center electrode has an outer layer, and a core provided within the outer layer and formed from a material higher in thermal conductivity than the outer layer. After a heat treatment, the outer layer has a high-hardness region having a hardness of 190 Hv or higher and a thickness of 30 μm to 200 μm, and an element supply region having a thickness of 50 μm or more.