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:
Jul. 06, 2004
Filed:
Feb. 26, 2003
NGK Spark Plug Co., Ltd., Aichi, JP;
Abstract
A spark plug having a tubular metallic shell ( ), an insulator ( ) fitted into the metallic shell ( ), a center electrode ( ) provided in the insulator ( ), and a ground electrode ( ), one end of the ground electrode ( ) being joined to the metallic shell ( ) by means of welding or a like process, and a spark discharge gap (g) being formed between the other end portion of the ground electrode ( ) and the center electrode ( ), the spark plug being further characterized in that: the ground electrode ( ) has an electrode base metal ( ), a Cu-based heat transfer acceleration element ( ) embedded in the electrode base metal ( ) and formed predominantly from Cu, and a noble metal chip ( ) welded to the electrode base metal ( ) at a position facing the spark discharge gap (g); and the electrode base metal ( ) is an Ni alloy containing Cr in an amount of 14%-17% by mass, Mo in an amount of 0.8%-3.5% by mass, and Ni in an amount of 68%-85.2% by mass. In a second embodiment, the ground electrode ( ) has a diffusion layer formed in a boundary between the electrode base metal ( ) and the Cu-based heat transfer acceleration element ( ), and the electrode base metal ( ) contains C in an amount not greater than 0.3% by mass.