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:
Aug. 26, 2003
Filed:
Feb. 26, 2002
NGK Spark Plug Co., Ltd., Aichi, JP;
Abstract
A tip portion of a center electrode of a spark plug includes a tapered portion which is tapered such that the diameter reduces axially frontward. A convex portion is formed at an axially intermediate position of the tapered portion so as to project radially outward with respect to an axis The axially measured distance L between the vertex of the convex portion (the convex vertex P) and the tip face D of an insulator is set to less than 0.5 mm. A heat release acceleration metal portion , which is made of Cu or an alloy that contains a predominant amount of Cu, is present at a position located a distance L of 1.5 mm as measured axially rearward from the convex vertex P in order to suppress spark erosion by lowering the temperature of the center electrode The heat release acceleration metal portion is formed such that an electrode base material , which encloses the heat release acceleration metal portion , has a wall thickness W of not less than 0.6 mm as measured at a position located 1.5 mm axially rearward from the convex vertex P.