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:
Oct. 27, 2015
Filed:
Aug. 02, 2013
Ngk Spark Plug Co., Ltd., Nagoya, JP;
NGK SPARK PLUG CO., LTD., Nagoya, JP;
Abstract
A spark plug includes a tip joined to a center electrode. The coefficient of linear thermal expansion of the center electrode is greater than that of the tip. The tip has a gap-forming portion having a maximum width of 1.2 mm or greater and forming a gap in cooperation with the ground electrode and a to-be-joined portion joined to the center electrode. At a position A which is shifted 0.1 mm from the forward end of the outer surface of the fusion portion toward the forward end side, the width of the to-be-joined portion measured on the cross section is smaller than the width of the gap-forming portion. The to-be-joined portion satisfies Dtw/Dw≦1.1, where Dtw represents the width of the to-be-joined portion at the position A, and Dw represents the width of the fusion portion at the forward end of the outer surface thereof.