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:
Jul. 10, 2012
Filed:
Jun. 01, 2009
Tsutomu Shibata, Owariasahi, JP;
Keita Nakagawa, Nagoya, JP;
Tsutomu Shibata, Owariasahi, JP;
Keita Nakagawa, Nagoya, JP;
NGK Spark Plug Co., Ltd., Aichi, JP;
Abstract
A spark plug having sufficient durability for an internal combustion engine can restrain a sharp increase in resistance of a resistor in spite of its reduced size. The spark plug comprises an insulator having an axial hole, a metallic shell provided on the outer circumference of the insulator, a center electrode inserted into a front end portion of the axial hole, a terminal electrode inserted into a rear end portion of the axial hole, and a ground electrode. A circular columnar resistor is disposed within the axial hole between the center electrode and the terminal electrode, thereby electrically connecting the center electrode and the terminal electrode. The resistor is composed of carbon black that serves as a conductive material, a glass powder, and ceramic particles. Each of the ceramic particles has a maximum particle size of 0.5 μm or less.