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:
Jun. 09, 2015
Filed:
Aug. 31, 2012
Kengo Fujimura, Ichinomiya, JP;
Hirokazu Kurono, Nagoya, JP;
Toshitaka Honda, Nagoya, JP;
NGK SPARK PLUG CO., LTD., Nagoya, JP;
Abstract
A spark plug includes: a center electrode including a rod portion and a head portion and having a diameter larger than the diameter of the rod portion; an insulator having an axial bore, the center electrode being disposed in the axial bore at its front end; and a seal portion for fixing the center electrode in the axial bore. The insulator comprises: a leg portion inner circumferential surface; a cylindrical trunk portion inner circumferential surface which surrounds the head portion; and a support surface which supports the head portion. The seal portion has: a seal portion outer circumferential surface; a seal portion abutment surface; and a connecting surface. In a cross section of the seal portion, a curve, which is part of the contour of the seal portion and is included in the connecting surface, has a radius of curvature R of 0.1 mm or more.