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. 10, 2012
Filed:
Mar. 26, 2009
Hirokazu Kurono, Nagoya, JP;
Toshitaka Honda, Nagoya, JP;
Hiroki Takeuchi, Aichi, JP;
Takeshi Mitsuoka, Kounan, JP;
Kuniharu Tanaka, Komaki, JP;
Katsuya Takaoka, Komaki, JP;
Hirokazu Kurono, Nagoya, JP;
Toshitaka Honda, Nagoya, JP;
Hiroki Takeuchi, Aichi, JP;
Takeshi Mitsuoka, Kounan, JP;
Kuniharu Tanaka, Komaki, JP;
Katsuya Takaoka, Komaki, JP;
NGK Spark Plug Co., Ltd., Aichi, JP;
Abstract
An object of the invention is to provide a spark plug including an insulator which is difficult to cause breakdown and exhibits higher withstand voltage characteristics. This invention relates to a spark plugincluding a center electrode, an insulatorand a grounding electrode, wherein the insulator is formed by an alumina-based sintered body which has a theoretical density ratio of 95.0% or more, which contains a rare earth element component, Si component, and at least two kinds of Group 2 element (2A) components, and in which the rare earth element being dispersed so as to satisfy the following condition: <Condition> when 7 places of measurement line (measurement length: 180 μm) are selected in the alumina-based sintered body and the rare earth element (RE) present in each of selected measurement lines is analyzed with an energy dispersion method, a total number of measurement lines in which 8 or more peaks derived from the rare earth element (RE) are observed is 4 places or more of the 7 places.