Patents by Inventor Yoshitomo IWASAKI
Yoshitomo IWASAKI has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 10777975Abstract: Disclosed is a spark plug including: an insulator having an axial through hole formed with a first hole region and a second hole region larger in inner diameter than the first hole region; a center electrode having a collar portion disposed in the second hole region; a resistor disposed in the second hole region, with a front end of the resistor being located apart from a rear end of the center electrode; and a conductive seal material arranged at least between the center electrode and the resistor within the second hole region, wherein the center electrode has a recess recessed from the rear end thereof toward the front, wherein the recess is provided at least at a location of a maximum outer diameter section of the collar portion, and wherein the conductive seal material is filled into the recess from the rear end of the center electrode.Type: GrantFiled: March 27, 2019Date of Patent: September 15, 2020Assignee: NGK SPARK PLUG CO., LTD.Inventors: Yoshitomo Iwasaki, Hironori Uegaki
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Publication number: 20190305523Abstract: Disclosed is a spark plug including: an insulator having an axial through hole formed with a first hole region and a second hole region larger in inner diameter than the first hole region; a center electrode having a collar portion disposed in the second hole region; a resistor disposed in the second hole region, with a front end of the resistor being located apart from a rear end of the center electrode; and a conductive seal material arranged at least between the center electrode and the resistor within the second hole region, wherein the center electrode has a recess recessed from the rear end thereof toward the front, wherein the recess is provided at least at a location of a maximum outer diameter section of the collar portion, and wherein the conductive seal material is filled into the recess from the rear end of the center electrode.Type: ApplicationFiled: March 27, 2019Publication date: October 3, 2019Applicant: NGK SPARK PLUG CO., LTD.Inventors: Yoshitomo IWASAKI, Hironori UEGAKI
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Patent number: 9843167Abstract: An electrically-conductive seal portion of a spark plug includes a large-diameter seal portion, a small-diameter seal portion having an outer diameter smaller than an outer diameter of the large-diameter seal portion, and a tapered seal portion disposed between the large-diameter seal portion and the small-diameter seal portion. An insulator includes a flange portion, a first middle-body portion having an outer diameter smaller than an outer diameter of the flange portion, a second middle-body portion having an outer diameter smaller than an outer diameter of the first middle-body portion, and a leg portion having an outer diameter that tapers toward a tip end of the spark plug. The tapered seal portion is disposed inside the first middle-body portion.Type: GrantFiled: October 12, 2016Date of Patent: December 12, 2017Assignee: NGK SPARK PLUG CO., LTD.Inventors: Hironori Uegaki, Yoshitomo Iwasaki
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Patent number: 9711951Abstract: A spark plug having a resistor disposed within a through hole of an insulator and between a center electrode and a metal terminal so as to be spaced apart from the center electrode in a direction of an axial line; and a conductive glass seal layer provided between the resistor and the center electrode and electrically connecting the resistor and the center electrode to each other, the conductive glass seal layer has a diameter of 3.9 mm or less, and a joined surface of the conductive glass seal layer and the resistor has a convex shape toward the center electrode side. A length ? from a rear end to a front end of the joined surface and a maximum length ? of the conductive glass seal layer in the direction of the axial line meets a relation of ?/??0.4.Type: GrantFiled: March 16, 2016Date of Patent: July 18, 2017Assignee: NGK SPARK PLUG CO., LTD.Inventors: Yoshitomo Iwasaki, Haruki Yoshida, Toshitaka Honda
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Publication number: 20170110854Abstract: An electrically-conductive seal portion of a spark plug includes a large-diameter seal portion, a small-diameter seal portion having an outer diameter smaller than an outer diameter of the large-diameter seal portion, and a tapered seal portion disposed between the large-diameter seal portion and the small-diameter seal portion. An insulator includes a flange portion, a first middle-body portion having an outer diameter smaller than an outer diameter of the flange portion, a second middle-body portion having an outer diameter smaller than an outer diameter of the first middle-body portion, and a leg portion having an outer diameter that tapers toward a tip end of the spark plug. The tapered seal portion is disposed inside the first middle-body portion.Type: ApplicationFiled: October 12, 2016Publication date: April 20, 2017Applicant: NGK Spark Plug Co., LTD.Inventors: Hironori Uegaki, Yoshitomo Iwasaki
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Patent number: 9614354Abstract: A resistor element of a spark plug containing ZrO2, wherein a target region is defined by a rectangular region where the size in the direction perpendicular to an axial line is 1800 ?m and the size in the direction of the axial line is 2400 ?m. In the case where the target region is divided into a plurality of square regions having lengths of 200 ?m on a side, a transverse line-shaped region is defined by a region in a line shape that is constituted of nine square regions arranged in the direction perpendicular to the axial line. A first type region is defined by the square region where a proportion of an area of ZrO2 is 25% or more, and a second type region is defined by the square region where a proportion of an area of ZrO2 is less than 25%.Type: GrantFiled: June 2, 2014Date of Patent: April 4, 2017Assignee: NGK SPARK PLUG CO., LTD.Inventors: Haruki Yoshida, Jumpei Kita, Yoshitomo Iwasaki, Toshitaka Honda
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Patent number: 9484718Abstract: A spark plug includes an insulator having an axial hole, a center electrode inserted into a forward portion of the axial hole, a terminal electrode inserted into a rear portion of the axial hole, and an interelectrode insert which contains glass and electrically conductive carbon and is disposed in the axial hole between the center electrode and the terminal electrode. The interelectrode insert has a resistance of 1.0 k? to 3.0 k?, and the interelectrode insert has a carbon content of 1.5% by mass to 4.0% by mass at a forward portion located forward of a center point between the rear end of the center electrode and the forward end of the terminal electrode. Furthermore, the forward portion is lower in resistance than a rear portion of the interelectrode insert located rearward of the center point.Type: GrantFiled: August 8, 2014Date of Patent: November 1, 2016Assignee: NGK SPARK PLUG CO., LTD.Inventors: Haruki Yoshida, Takamitsu Mizuno, Masaaki Kumagai, Jumpei Kita, Yoshitomo Iwasaki, Toshitaka Honda
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Publication number: 20160285242Abstract: A spark plug having a resistor disposed within a through hole of an insulator and between a center electrode and a metal terminal so as to be spaced apart from the center electrode in a direction of an axial line; and a conductive glass seal layer provided between the resistor and the center electrode and electrically connecting the resistor and the center electrode to each other, the conductive glass seal layer has a diameter of 3.9 mm or less, and a joined surface of the conductive glass seal layer and the resistor has a convex shape toward the center electrode side. A length ? from a rear end to a front end of the joined surface and a maximum length ? of the conductive glass seal layer in the direction of the axial line meets a relation of ?/??0.4.Type: ApplicationFiled: March 16, 2016Publication date: September 29, 2016Applicant: NGK SPARK PLUG CO., LTD.Inventors: Yoshitomo IWASAKI, Haruki YOSHIDA, Toshitaka HONDA
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Publication number: 20160204580Abstract: A spark plug includes an insulator having an axial hole, a center electrode inserted into a forward portion of the axial hole, a terminal electrode inserted into a rear portion of the axial hole, and an interelectrode insert which contains glass and electrically conductive carbon and is disposed in the axial hole between the center electrode and the terminal electrode. The interelectrode insert has a resistance of 1.0 k? to 3.0 k?, and the interelectrode insert has a carbon content of 1.5% by mass to 4.0% by mass at a forward portion located forward of a center point between the rear end of the center electrode and the forward end of the terminal electrode. Furthermore, the forward portion is lower in resistance than a rear portion of the interelectrode insert located rearward of the center point.Type: ApplicationFiled: August 8, 2014Publication date: July 14, 2016Applicant: NGK SPARK PLUG CO., LTD.Inventors: Haruki YOSHIDA, Takamitsu MIZUNO, Masaaki KUMAGAI, Jumpei KITA, Yoshitomo IWASAKI, Toshitaka HONDA
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Publication number: 20160204579Abstract: A resistor element of a spark plug containing ZrO2, wherein a target region is defined by a rectangular region where the size in the direction perpendicular to an axial line is 1800 ?m and the size in the direction of the axial line is 2400 ?m. In the case where the target region is divided into a plurality of square regions having lengths of 200 ?m on a side, a transverse line-shaped region is defined by a region in a line shape that is constituted of nine square regions arranged in the direction perpendicular to the axial line. A first type region is defined by the square region where a proportion of an area of ZrO2 is 25% or more, and a second type region is defined by the square region where a proportion of an area of ZrO2 is less than 25%.Type: ApplicationFiled: June 2, 2014Publication date: July 14, 2016Applicant: NGK SPARK PLUG CO., LTD.Inventors: Haruki YOSHIDA, Jumpei KITA, Yoshitomo IWASAKI, Toshitaka HONDA
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Publication number: 20150318672Abstract: A spark plug includes an insulator with an axial through hole, a center electrode disposed in a front side of the through hole and a metal terminal disposed in a rear side of the through hole. The spark plug further includes a front conductive glass seal layer, a first resistor, a rear conductive glass seal layer, a seal contact member, a second resistor and a conductive elastic material arranged, in this order from the front to the rear, between the center electrode and the metal terminal within the through hole. The first resistor is formed containing at least a conductive material and a glass material. The second resistor is formed as a wire wound resistor having 30 or more turns of wire.Type: ApplicationFiled: April 30, 2015Publication date: November 5, 2015Applicant: NGK SPARK PLUG CO., LTD.Inventors: Yoshitomo IWASAKI, Haruki YOSHIDA