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:
May. 15, 2012
Kaori Suzuki, Ohbu, JP;
Kaori Suzuki, Ohbu, JP;
NGK SPARK PLUG CO., LTD., Aichi, JP;
Abstract
A spark plug includes a center electrode, a ceramic insulator provided with an axial hole, a metal shell, and a ground electrode having a facing surface that faces a leading end surface of the center electrode. An annular space is formed between an outer peripheral surface of the center electrode and an inner peripheral surface of the axial hole and is opened toward a leading end side, and when C (mm) is a distance between the outer peripheral surface of the center electrode and the inner peripheral surface of the axial hole in the opening of the annular space, C≧0.2 mm is satisfied. In a cross-section which includes the axial line and is orthogonal to the center axis of the ground electrode, a contour line of lateral surfaces of the ground electrode has a curved shape convexed outward.