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:
Mar. 03, 2015
Filed:
Sep. 19, 2014
Ngk Spark Plug, Co., Ltd., Nagoya, JP;
NGK Spark Plug Co., Ltd., Nagoya, JP;
Abstract
An ignition plug includes an insulator having an axial hole extending therethrough in the direction of an axis, a center electrode inserted into a forward end portion of the axial hole, and a metallic shell disposed externally of the insulator. The insulator includes a step portion engaged with an inner circumferential portion of the metallic shell and a leg portion extending forward from the forward end of the step portion. The porosity of the leg portion is 3.0% or less. Among three regions of the leg portion that are radially trisected in a cross section perpendicular to the axis, the outermost region is defined as a first region and the innermost region is defined as a second region. The porosity of the first region is equal to or more than 1.20 times the porosity of the second region.