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:
Jan. 14, 2014
Filed:
Apr. 30, 2010
Kohei Katsuraya, Nagoya, JP;
Hiroyuki Kameda, Nagakute, JP;
Katsutoshi Nakayama, Nagoya, JP;
NGK Spark Plug Co., Ltd., Nagoya, JP;
Abstract
A spark plug includes a center electrode extending in an axial direction; an insulator formed externally of the outer circumference of the center electrode; a metallic shell formed externally of the outer circumference of the insulator and having a ledge which supports the insulator; and a ground electrode joined to the metallic shell. The insulator has a support portion which faces the ledge. A 'frontward direction' is defined as the direction parallel to the axial direction toward a spark portion formed between the center electrode and the ground electrode. The insulator has a diameter reduction portion whose outside diameter reduces along the frontward direction from the support portion, and a diameter increase portion whose outside diameter increases along the frontward direction from the front end of the diameter reduction portion. This restrains the generation of leak current while maintaining heat resistance of the spark plug.