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. 01, 2016
Filed:
Jul. 16, 2013
Ngk Spark Plug Co., Ltd., Nagoya, JP;
Keiji Ozeki, Konan, JP;
Tomoaki Kato, Nagoya, JP;
Naoyuki Mukoyama, Nisshin, JP;
Tsutomu Kobayashi, Inazawa, JP;
NGK SPARK PLUG CO., LTD., Nagoya, JP;
Abstract
A spark plug includes a ceramic insulator having an engagement portion, and a metallic shell provided around the ceramic insulator and having a protrusion. The protrusion has a diameter-decreasing portion, which seats on the engagement portion via an annular seat packing. On a cross section including an axial line, θs>θp is satisfied, where θp represents an acute angle (°) between a straight line orthogonal to the axial line and the contour of the engagement portion, and θs represents an acute angle (°) between a straight line orthogonal to the axial line and the contour of the diameter-decreasing portion. In the aforementioned cross section, Hvo>Hvi is satisfied, where Hvo represents the Vickers hardness (Hv) of the seat packing at the midpoint of a first line segment, and Hvi represents the Vickers hardness (Hv) of the seat packing at the midpoint of a second line segment.