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:
Sep. 17, 2024
Filed:
Jun. 14, 2022
Niterra Co., Ltd., Aichi, JP;
Noriyuki Tamura, Aichi, JP;
Haruki Yoshida, Aichi, JP;
Hiroki Shimada, Aichi, JP;
Tomoya Kukino, Aichi, JP;
Takuto Koba, Aichi, JP;
Kengo Fujimura, Aichi, JP;
NITERRA CO., LTD., Nagoya, JP;
Abstract
A spark plugof the present invention includes: an insulatormade from an alumina-based sintered body; a center electrode being a bar-like electrode inserted in the insulatorand having, on a rear end side of the center electrode, a diameter-enlarged portion enlarged in a radial direction and engaged with an inner wall of the insulator; and a conductive sealing material provided on the rear end side of the center electrodeinside the insulator. In a mirror-polished surface obtained by mirror-polishing a cut surface obtained by cutting the insulator in a direction perpendicular to the axial line direction, at a position 2 mm from a portion having a maximum diameter of the diameter-enlarged portion to the rear end side along the axial line direction, when 20 observation regions each being 192 μm×255 μm are set so as to each overlap a reference position being a center position between an inner peripheral surface and an outer peripheral surface of the insulator and so as not to overlap each other, an average of a proportion (porosity) of pores included in each observation region is not greater than 3.5% and, with respect to a variation in the proportion (porosity), when a standard deviation is defined as σ, σ is not greater than 0.36.