公开(公告)号：US20170093132A1

公开(公告)日：2017-03-30

申请号：US15265152

申请日：2016-09-14

Applicant: NGK Spark Plug Co., LTD.

Inventor： Jumpei ISASA ,  Haruki YOSHIDA ,  Yutaka YOKOYAMA ,  Kuniharu TANAKA ,  Nobuyoshi ARAKI ,  Toshiki KON

IPC: H01T13/38

CPC classification number: H01T13/38

Abstract: A spark plug includes an insulator made of an alumina sintered body containing Al2O3 as a principal component and additional components including; an Si component, a Ba component, an Mg component, a Ca component, an Sr component, and a rare earth element component. When the additional components are expressed as oxides including RSiO2, RBaO, RMgO, RCaO, RSrO, and RRE2O3, contents (mass %) of the sub-component satisfy expressions (1) to (6) as follows: (1) 1.0≦RSiO2≦5.0; (2) 0.5≦RBaO≦5.0; (3) 0≦RMgO≦0.18; (4) 0≦RMgO/RBaO≦0.36; (5) 0.3≦(RMgO+RCaO+RSiO)≦1.8; and (6) 0≦RRE2O3≦0.1.

公开(公告)号：US20170093134A1

公开(公告)日：2017-03-30

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：US20170093133A1

公开(公告)日：2017-03-30

申请号：US15272561

申请日：2016-09-22

Applicant: NGK SPARK PLUG CO., LTD.

Inventor： Haruki YOSHIDA ,  Jumpei ISASA ,  Toshitaka HONDA ,  Yutaka YOKOYAMA ,  Kuniharu TANAKA ,  Nobuyoshi ARAKI ,  Toshiki KON

IPC: H01T13/38 ,  H01T13/18

CPC classification number: H01T13/38 ,  H01T13/18 ,  H01T13/60 ,  H01T21/02

Abstract: A spark plug includes an insulator, a center electrode, a metallic shell, and a ground electrode. The insulator contains not less than 90.0 mass % and not greater than 98.1 mass % of Al2O3 with respect to a total mass of elements, as reduced to oxides, contained in the insulator, and has a porosity not greater than 5%. Assuming that a porosity of the insulator after a heat treatment is B, a difference (B−A) of the porosities before and after the heat treatment is not greater than 3.5%. In the heat treatment, the insulator is placed in a furnace, and a temperature in the furnace is increased from a room temperature to 1400° C. at a temperature increase rate of 7° C./min and is held at 1400° C. for 30 minutes, and thereafter, the temperature is decreased from 1400° C. to 400° C. at a temperature decrease rate of 10° C. or less per 5 minutes and is decreased to the room temperature.

公开(公告)号：US20190131776A1

公开(公告)日：2019-05-02

申请号：US16095788

申请日：2017-05-25

Applicant: NGK SPARK PLUG CO., LTD.

Inventor： Jumpei ISASA ,  Seiji NAKANO ,  Hirokazu KURONO ,  Kuniharu TANAKA ,  Yutaka YOKOYAMA ,  Haruki YOSHIDA ,  Shun KONDO

IPC: H01T13/32 ,  H01T13/06

CPC classification number: H01T13/32 ,  H01T13/06 ,  H01T13/14 ,  H01T13/20

Abstract: Provided is a spark plug capable of ensuring fouling resistance with a simple configuration. An insulator includes a step portion formed on an outer circumferential surface thereof. A center electrode is arranged in an axial hole of the insulator. A cylindrical metal shell having a shelf portion formed on an inner circumferential surface thereof is arranged radially outside the insulator. The insulator further includes a front end portion located frontward of the step portion. An outer circumferential surface of the front end portion has an arithmetic average roughness of 0.5 μm or smaller in a circumferential direction. A recess is formed with a depth of 3 to 20 μm in at least part of an end surface and the outer circumferential surface of the front end portion so as to extend from the front toward the rear.

公开(公告)号：US20180048126A1

公开(公告)日：2018-02-15

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: H01T13/38 ,  C04B35/10 ,  H01B3/12

CPC classification number: H01T13/38 ,  C04B35/10 ,  C04B35/111 ,  C04B35/62655 ,  C04B35/63416 ,  C04B2235/3206 ,  C04B2235/3208 ,  C04B2235/3213 ,  C04B2235/3215 ,  C04B2235/3217 ,  C04B2235/3222 ,  C04B2235/3418 ,  C04B2235/3481 ,  C04B2235/5436 ,  C04B2235/5445 ,  C04B2235/6565 ,  C04B2235/6567 ,  C04B2235/85 ,  H01B3/12

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：US20180374601A1

公开(公告)日：2018-12-27

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 ,  H01T13/38 ,  C04B35/117

CPC classification number: H01B3/12 ,  C04B35/111 ,  C04B35/117 ,  C04B2235/3201 ,  C04B2235/3206 ,  C04B2235/3208 ,  C04B2235/3215 ,  C04B2235/3217 ,  C04B2235/3227 ,  C04B2235/3418 ,  C04B2235/72 ,  C04B2235/725 ,  C04B2235/77 ,  C04B2235/781 ,  C04B2235/785 ,  C04B2235/85 ,  C04B2235/96 ,  H01T13/38 ,  H01T13/60

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：US20170353013A1

公开(公告)日：2017-12-07

申请号：US15607714

申请日：2017-05-30

Applicant: NGK SPARK PLUG CO., LTD.

Inventor： Haruki YOSHIDA ,  Kuniharu TANAKA ,  Yutaka YOKOYAMA ,  Shun KONDO ,  Hirokazu KURONO ,  Toshimasa SAJI

IPC: H01T13/20 ,  H01T13/39 ,  H01T13/06

Abstract: A spark plug having an insulator with a leg portion whose outer circumferential surface has an arithmetic mean roughness Ra of 0.5 μm or less. The leg portion has a first section, a second section, and a third section. The first section has an outer diameter that decreases toward the forward end of the first section. The second section is located forward of and adjacent to the first section and its outer diameter decreases toward the forward end of the second section. The outer circumferential surface of the second section is located inward of a first straight line passing through the base and forward ends of the outer circumferential surface of the first section. The third section is located forward of and adjacent to the second section. The outer diameter of the third section is equal to or less than a forward end outer diameter Ds of the second section over the entire third section.

公开(公告)号：US20140336035A1

公开(公告)日：2014-11-13

申请号：US14273026

申请日：2014-05-08

Applicant: NGK SPARK PLUG CO., LTD.

Inventor： Katsuya TAKAOKA ,  Yutaka YOKOYAMA ,  Kengo FUJIMURA ,  Hironori UEGAKI ,  Hiroki TAKEUCHI ,  Hirokazu KURONO ,  Toshitaka HONDA ,  Kuniharu TANAKA ,  Takeshi MITSUOKA

IPC: H01T13/38 ,  C04B35/50 ,  C04B35/505

CPC classification number: H01T13/38 ,  C04B35/111 ,  C04B2235/3206 ,  C04B2235/3208 ,  C04B2235/3213 ,  C04B2235/3215 ,  C04B2235/3224 ,  C04B2235/3225 ,  C04B2235/3227 ,  C04B2235/3229 ,  C04B2235/3232 ,  C04B2235/3241 ,  C04B2235/3244 ,  C04B2235/3251 ,  C04B2235/3262 ,  C04B2235/3272 ,  C04B2235/3418 ,  C04B2235/786 ,  C04B2235/85

Abstract: An insulator for spark plug with a main constituent of alumina and containing silicon includes a grain boundary phase positioned between alumina particles. The grain boundary phase contains: a group 2A element; a rare earth element; and at least one kind of zirconium, titanium, chrome, niobium, manganese, and iron (a first element). Assuming that a total amount of the rare earth element is X (mass %), a total amount of the group 2A element is Y (mass %), and a total amount of the first element is Z (mass %), the following are met: 0.40≦Y/X≦2.00 0.10≦Z/X≦0.40.

Abstract translation: 具有主要成分为氧化铝和含硅的火花塞的绝缘体包括位于氧化铝颗粒之间的晶界相。 晶界相包含：2A族元素; 稀土元素; 和至少一种锆，钛，铬，铌，锰和铁（第一元素）。 假设稀土元素的总量为X（质量％），则2A族元素的总量为Y（质量％），第一元素的总量为Z（质量％），以下为 满足：0.40＆nlE; Y / X＆nlE; 2.00 0.10＆nlE; Z / X＆lt;