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. 22, 2013
Filed:
Jun. 23, 2010
Hirokazu Kurono, Nagoya, JP;
Toshitaka Honda, Nagoya, JP;
Katsuya Takaoka, Ichinomiya, JP;
Hiroki Takeuchi, Aichi, JP;
Kuniharu Tanaka, Komaki, JP;
Takeshi Mitsuoka, Konan, JP;
Hirokazu Kurono, Nagoya, JP;
Toshitaka Honda, Nagoya, JP;
Katsuya Takaoka, Ichinomiya, JP;
Hiroki Takeuchi, Aichi, JP;
Kuniharu Tanaka, Komaki, JP;
Takeshi Mitsuoka, Konan, JP;
NGK Spark Plug Co., Ltd., Aichi, JP;
Abstract
A spark plug that is equipped with an insulator that has a stem portion on a front end side, a center electrode, and a main metal member that retains the insulator at an engaging projection portion, wherein an inner diameter Dof the engaging projection portion, the maximum outer diameter dof the stem portion, which faces an inner circumferential surface of the engaging projection portion, its inner diameter d, and dielectric constant ∈ of the insulator satisfy the condition of '(D−d)/2≦0.40 (mm)', '(d−d)/2≦1.65 (mm)', and “∈≧9.4”.