公开(公告)号：US10348061B2

公开(公告)日：2019-07-09

申请号：US16018949

申请日：2018-06-26

Applicant: NGK SPARK PLUG CO., LTD.

Inventor： Hideto Yamada ,  Haruki Yoshida ,  Kuniharu Tanaka ,  Michitaka Yamada ,  Yusuke Nomura

IPC: H01T13/38 ,  H01T13/60 ,  B82Y30/00 ,  C04B35/64 ,  C04B35/111 ,  C04B35/117 ,  C04B35/626

Abstract: The spark plug includes an insulator formed of an alumina-based sintered body, and the insulator contains Si, Ba, and a rare earth element. In an analysis of the insulator by using a scanning transmission electron microscope having an electron-probe diameter of 1 nm, Si and a rare earth element are detected at a crystal grain boundary having a thickness of 15 nm or less, a content of an alkaline earth metal is less than a detection limit at the crystal grain boundary, and a diffraction spot is present in an electron diffraction pattern of a portion where Ba is detected.

公开(公告)号：US10586627B2

公开(公告)日：2020-03-10

申请号：US16015967

申请日：2018-06-22

Applicant: NGK SPARK PLUG CO., LTD.

Inventor： Haruki Yoshida ,  Kuniharu Tanaka ,  Shun Kondo ,  Yutaka Yokoyama ,  Yusuke Nomura ,  Michitaka Yamada

IPC: H01B3/12 ,  C04B35/117 ,  H01T13/38 ,  H01T13/60 ,  C04B35/111

Abstract: The spark plug includes an insulator made from an alumina-based sintered body, and the insulator contains 90 to 98 wt % of an Al component in oxide equivalent. The insulator contains 1 to 5 wt % of an Si component, 0.1 to 1 wt % of an Mg component, 2 wt % or less of a Ca component, 0.3 to 6 wt % of a Ba component, and 0.11 to 5 wt % of a rare earth component, in oxide equivalent. In analysis using a scanning transmission electron microscope with a probe diameter of an electron beam set at 1 nm, Si and a rare earth element are detected at a crystal grain boundary having a thickness of 15 nm or less, and an alkaline earth metal at the crystal grain boundary is less than a detection limit.

公开(公告)号：US10193311B2

公开(公告)日：2019-01-29

申请号：US15669536

申请日：2017-08-04

Applicant: NGK Spark Plug Co., LTD.

Inventor： Yutaka Yokoyama ,  Kuniharu Tanaka ,  Nobuyoshi Araki ,  Hirokazu Kurono ,  Toshimasa Saji ,  Yusuke Nomura ,  Jumpei Isasa

IPC: C04B35/10 ,  H01T13/18 ,  H01T13/38 ,  H01B3/12 ,  C04B35/111 ,  C04B35/626 ,  C04B35/634

Abstract: An alumina-based sintered body includes 92 mass % to 96 mass % of Al in terms of an oxide, and at least three elements selected from Group II elements, one of the at least three elements being 1.90 mass % or more of Ba in terms of an oxide. The alumina-based sintered body includes the following phases in a grain boundary phase present between alumina crystal grains: a first crystal phase containing Si and at least one of the Group II elements, and a second crystal phase containing Al and at least one of the Group II elements. In X-ray diffraction of the alumina-based sintered body, the maximum relative intensity of the first crystal phase and the maximum relative intensity of the second crystal phase are both 2 or above relative to the maximum diffraction intensity of the alumina crystal.

公开(公告)号：US09653888B2

公开(公告)日：2017-05-16

申请号：US15272807

申请日：2016-09-22

Applicant: NGK SPARK PLUG CO., LTD.

Inventor： Yutaka Yokoyama ,  Kuniharu Tanaka ,  Katsuya Takaoka ,  Shun Kondo ,  Nobuyoshi Araki ,  Toshiki Kon ,  Haruki Yoshida ,  Jumpei Isasa ,  Hirokazu Kurono ,  Hironori Uegaki ,  Toshimasa Saji ,  Yusuke Nomura

IPC: H01T13/38

CPC classification number: H01T13/38 ,  H01T13/60

Abstract: A spark plug including an insulator containing not less than 92 mass % and not greater than 96 mass % of Al component in terms of oxide, wherein the insulator is formed from an alumina sintered body comprising alumina crystal and a grain boundary phase present between crystal grains of the alumina crystal. Assuming that mass contents of an Si component, an Mg component, a Ba component, and a Ca component in terms of oxide are represented by MSiO2, MMgO, MBaO, and MCaO, respectively, and a sum of MSiO2, MMgO, MBaO, and MCaO is represented by Mt, the grain boundary phase contains these components so as to satisfy conditions (1) to (4) as follows: (1) 0.17≦MSiO2/Mt≦0.47; (2) 0.005≦MMgO/Mt≦0.07; (3) 0.29≦MBaO/Mt≦0.77; (4) 0.03≦MCaO/Mt≦0.19.

公开(公告)号：US11183819B2

公开(公告)日：2021-11-23

申请号：US16574170

申请日：2019-09-18

Applicant: NGK SPARK PLUG CO., LTD.

Inventor： Yutaka Yokoyama ,  Nobuyoshi Araki ,  Kuniharu Tanaka ,  Haruki Yoshida ,  Hironori Uegaki ,  Toshiki Kon ,  Yusuke Nomura

IPC: H01T13/38 ,  H01B3/12 ,  C04B35/111

Abstract: A spark plug according to one embodiment of the present invention includes an insulator formed of an alumina-based sintered body, wherein the insulator contains 90 wt % or more of an aluminum component in terms of oxide, and wherein crystal grains of the insulator has an average grain size of 1.5 mm or smaller and a grain size standard deviation of 1.2 μm or smaller.

公开(公告)号：US10305260B2

公开(公告)日：2019-05-28

申请号：US16033661

申请日：2018-07-12

Applicant: NGK SPARK PLUG CO., LTD.

Inventor： Haruki Yoshida ,  Kuniharu Tanaka ,  Toshinori Takeichi ,  Michitaka Yamada ,  Yusuke Nomura

IPC: H01T13/34 ,  H01T13/52 ,  H01T13/46

Abstract: Disclosed is a spark plug including: an insulator having an axial hole formed along an axis of the spark plug; a center electrode disposed in a front end side of the axial hole; and a metal shell fixed around an outer circumference of the insulator, with a front end portion of the insulator protruding frontward from a front end of the metal shell. The front end portion of the insulator consists only of a first section and a second section located adjacent to and frontward of the first section and having an inner diameter larger than that of the first section. The second section has a chamfered area formed on an inner circumferential surface thereof so as to continue to a front end of the insulator.