Patents by Inventor Manabu Kubota

Manabu Kubota 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).

  • Publication number: 20210041631
    Abstract: A fiber module (1B) according to the present disclosure includes an input-side optical fiber (11), an output-side optical fiber (12), a ferrule (20) in which the input-side optical fiber and the output-side optical fiber are insertable in both ends and a groove (32) is formed in a direction orthogonal to a longitudinal direction (D1) in the middle of the longitudinal direction, a dielectric multilayer film filter (30) inserted in the groove, and an input-side GI fiber (15) and an output-side GI fiber (16) joined by fusion to respective terminal portions of the input-side optical fiber and the output-side optical fiber. The dielectric multilayer film filter is interposed between an end surface (15f) of the input-side GI fiber and an end surface (16f) of the output-side GI fiber in the longitudinal direction.
    Type: Application
    Filed: February 28, 2019
    Publication date: February 11, 2021
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Kengo HORIKOSHI, Takashi YAMADA, Hisao YOSHINAGA, Shunsuke KANAI, Manabu KUBOTA
  • Patent number: 10889870
    Abstract: In this steel component, the concentration of C in a surface layer is 0.85 mass % or more to 1.2 mass % or less, which is higher than the concentration of C in a starting material steel, the surface layer has a volume ratio of a retained-austenite structure higher than 0% and lower than 10%, the remainder of the surface layer is a martensitic structure, the area fraction of grain boundary carbides in the surface layer is lower than 2%, a layer inside the surface layer is higher than the surface layer in a volume ratio of a retained-austenite structure, and in the layer inside the surface layer, the remainder is a martensitic structure.
    Type: Grant
    Filed: March 8, 2017
    Date of Patent: January 12, 2021
    Assignees: AISIN AW CO., LTD., NIPPON STEEL CORPORATION
    Inventors: Koji Obayashi, Kazuaki Okada, Keisuke Matsuzaka, Masashi Sakakibara, Manabu Kubota, Kei Miyanishi, Tatsuya Koyama
  • Patent number: 10844466
    Abstract: There is provided a hot forging steel including, by mass %, C: more than 0.30% and less than 0.60%, Si: 0.10% to 0.90%, Mn: 0.50% to 2.00%, S: 0.010% to 0.100%, Cr: 0.01% to 1.00%, Al: more than 0.005% and 0.100% or less, N: 0.0030% to 0.0200%, Bi: more than 0.0001% and 0.0050% or less, Ti: 0% or more and less than 0.040%, V: 0% to 0.30%, Ca: 0% to 0.0040%, Pb: 0% to 0.40%, and a remainder including Fe and impurities, in which P and O in the impurities are respectively P: 0.050% or less and O: 0.0050% or less, an expression d+3?<20 is satisfied, and a presence density of MnS having an equivalent circle diameter of smaller than 2.0 ?m is 300 pieces/mm2 or more in a cross section parallel to a rolling direction of a steel.
    Type: Grant
    Filed: September 30, 2016
    Date of Patent: November 24, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Akira Shiga, Suguru Yoshida, Manabu Kubota, Hajime Hasegawa, Hideo Mizukami
  • Publication number: 20200269632
    Abstract: To provide a railway wheel which is excellent in corrosion fatigue resistance. The railway wheel according to the present embodiment has a chemical composition consisting of: in mass %, C: 0.65 to 0.80%, Si: 0.10 to 1.0%, Mn: 0.10 to 1.0%, P: not more than 0.030%, S: not more than 0.030%, Cr: 0.05 to 0.20%, Sn: 0.005 to 0.50%, Al: 0.010 to 0.050%, N: 0.0020 to 0.015%, Cu: 0 to 0.20%, Ni: 0 to 0.20%, Mo: 0 to 0.20%, V: 0 to 0.20%, Nb: 0 to 0.030%, and Ti: 0 to 0.030%, with the balance being Fe and impurities. A plate portion has a matrix structure composed of pearlite.
    Type: Application
    Filed: February 28, 2017
    Publication date: August 27, 2020
    Inventor: Manabu Kubota
  • Patent number: 10752969
    Abstract: Steel for a suspension spring including, as a chemical composition, by % by mass: C: more than 0.40% and 0.65% or less; Si: 1.00% to 3.50%; Mn: more than 2.00% and 3.00% or less; Cr: 0.01% to 2.00%; V: 0.02% to 0.50%; P: 0.020% or less; S: 0.020% or less: N: 0.0100% or less; and a remainder of Fe and impurities, in which Kf is 280 or more, in which a structure contains a tempered martensite of which an area ratio is 90% or more, in which a Fe-based carbide precipitated in the tempered martensite is a cementite, and in which an average of an area ratios of prior austenite grains which stretch in a longitudinal direction of the steel and of which an aspect ratio exceeds 3.0, is 80% or more in a case of depths of 0.1 mm, 0.2 mm, and 0.3 mm in a sheet thickness direction from a surface of the steel.
    Type: Grant
    Filed: March 10, 2016
    Date of Patent: August 25, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Manabu Kubota, Koichi Banno, Keisuke Chiba, Ryuuichi Seki
  • Patent number: 10724125
    Abstract: Spring steel includes: as a chemical composition, by mass %, C: 0.40% to 0.60%, Si: 0.90% to 2.50%, Mn: 0.20% to 1.20%, Cr: 0.15% to 2.00%, Ni: 0.10% to 1.00%, Ti: 0.030% to 0.100%, B: 0.0010% to 0.0060%, N: 0.0010% to 0.0070%, Cu: 0% to 0.50%, Mo: 0% to 1.00%, V: 0% to 0.50%, Nb: 0% to 0.10%, P: limited to less than 0.020%, S: limited to less than 0.020%, Al: limited to less than 0.050%, and a remainder including Fe and impurities, in a case where [Ti] represents a Ti content and [N] represents a N content by mass %, the chemical composition satisfies ([Ti]?3.43×[N])>0.03, and a total number density of a Ti carbide and a Ti carbonitride having a diameter of 5 nm to 100 nm is more than 50 piece/?m3.
    Type: Grant
    Filed: May 13, 2016
    Date of Patent: July 28, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Takahisa Suzuki, Manabu Kubota, Shuji Kozawa, Hirotsugu Miyamoto
  • Publication number: 20200102623
    Abstract: A railway wheel in which formation of pro-eutectoid cementite is suppressed is stably produced. After heating an intermediate product containing, in mass %, C: 0.80 to 1.15% to a temperature not less than Acm transformation point, the intermediate product is cooled such that the cooling rate (° C./sec) in a range from 800 to 500° C. satisfies the following conditions: Surface other than the tread and the flange surface: not more than Fn1 defined by Formula (1), Cooling rate in a region in which cooling rate is slowest: not less than Fn2 defined by Formula (1), and Tread and flange surface: not less than Fn2: Fn1=?5.0+exp(5.651?1.427×C?1.280×Si?0.7723×Mn?1.815×Cr?1.519×Al?7.798×V)??(1) Fn2=0.515+exp(?24.816+24.121×C+1.210×Si+0.529×Mn+2.458×Cr?15.116×Al?5.
    Type: Application
    Filed: March 30, 2018
    Publication date: April 2, 2020
    Inventors: Taketo MAEJIMA, Manabu KUBOTA
  • Patent number: 10597765
    Abstract: A steel according to an aspect of the present invention has a chemical composition within a predetermined range, in which a hardenability index Ceq ranges from greater than 7.5 to smaller than 44.0, a metallographic structure includes ferrite ranging from 85 to 100 area %, an average distance between sulfides, which are observed in a cross section parallel to a rolling direction of the steel and have an equivalent circle diameter ranging from 1 ?m or greater to smaller than 2 ?m, is shorter than 30.0 ?m, and a presence density of the sulfides, which are observed in the cross section parallel to the rolling direction of the steel and have an equivalent circle diameter ranging from 1 ?m or greater to smaller than 2 ?m, is 300 pieces/mm2 or more.
    Type: Grant
    Filed: November 25, 2016
    Date of Patent: March 24, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Akira Shiga, Manabu Kubota, Hajime Hasegawa, Hideo Mizukami
  • Publication number: 20200070569
    Abstract: Provided is a railway wheel capable of suppressing formation of pro-eutectoid cementite even if the C content is high. A railway wheel according to an embodiment of the present invention has a chemical composition consisting of: in mass %, C: 0.80 to 1.15%; Si: 0.45% or less; Mn: 0.10 to 0.85%; P: 0.050% or less; S: 0.030% or less; Al: 0.120 to 0.650%; N: 0.0030 to 0.0200%; Cr: 0 to 0.25%; and V: 0 to 0.12%, with the balance being Fe and impurities, wherein an amount of pro-eutectoid cementite, which is defined by Formula (1), in a microstructure of the railway wheel is not more than 1.50 pieces/100 ?m: Amount of pro-eutectoid cementite (pieces/ 100 ?m)=a total sum of the number of pieces of pro-eutectoid cementite which intersect with two diagonal lines in a square visual field of 200 ?m×200 ?m/(5.
    Type: Application
    Filed: March 30, 2018
    Publication date: March 5, 2020
    Inventors: Taketo MAEJIMA, Manabu KUBOTA
  • Publication number: 20200038959
    Abstract: A sintered friction material is formed by pressure sintering mixed powder at 800° C. or above, the mixed powder consisting of, in mass %, Cu and/or Cu alloy: 40.0 to 80.0%, Ni: 0% or more and less than 5.0%, Sn: 0 to 10.0%, Zn: 0 to 10.0%, VC: 0.5 to 5.0%, Fe and/or Fe alloy: 2.0 to 40.0%, lubricant: 5.0 to 30.0%, metal oxide and/or metal nitride: 1.5 to 30.0%, and the balance being impurity.
    Type: Application
    Filed: April 7, 2017
    Publication date: February 6, 2020
    Applicants: NIPPON STEEL CORPORATION, FINE SINTER CO., LTD.
    Inventors: Manabu KUBOTA, Naomitsu MIZUI, Fumio ISHIMOTO, Kazutaka ASABE, Osamu KANDA, Satoru NAKANO, Takeshi NAKANO, Kazumichi KAWASAKI, Isao SHIMAZOE
  • Publication number: 20190292634
    Abstract: There is provided a sintered friction material for railway vehicles that has excellent frictional properties and wear resistance even in a high speed range of 280 km/hour or more. The sintered friction material for railway vehicles is a green compact sintered material containing, in mass %, Cu: 50.0 to 75.0%, graphite: 5.0 to 15.0%, one or more selected from the group consisting of magnesia, zircon sand, silica, zirconia, mullite, and silicon nitride: 1.5 to 15.0%, one or more selected from the group consisting of W and Mo: 3.0 to 30.0%, and one or more selected from the group consisting of ferrochromium, ferrotungsten, ferromolybdenum, and stainless steel: 2.0 to 20.0%, with the balance being impurities.
    Type: Application
    Filed: November 30, 2017
    Publication date: September 26, 2019
    Inventors: Manabu KUBOTA, Kazutaka ASABE, Yuki ICHIKAWA, Takeshi NAKANO, Tokitake OKAHIRA, Isao SHIMAZOE
  • Publication number: 20190264305
    Abstract: A steel for cold forging has a predetermined chemical composition, satisfies d+3??10.0 and SA/SB<0.30, includes 1200/mm2 or more of sulfides having an equivalent circle diameter of 1.0 to 10.0 ?m in a microstructure, and has an average distance between the sulfides of less than 30.0 ?m. Here, d is an average value of equivalent circle diameters of sulfides having an equivalent circle diameter of 1.0 ?m or more, ? is a standard deviation of the equivalent circle diameters of the sulfides having an equivalent circle diameter of 1.0 ?m or more, SA is the number of sulfides having an equivalent circle diameter of 1.0 ?m or more and less than 3.0 ?m, and SB is the number of the sulfides having an equivalent circle diameter of 1.0 ?m or more.
    Type: Application
    Filed: September 30, 2016
    Publication date: August 29, 2019
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Akira SHIGA, Manabu KUBOTA, Hajime HASEGAWA
  • Patent number: 10391742
    Abstract: A steel for a carburizing and a carburized steel component having a steel portion and a carburized layer with a thickness of more than 0.4 mm to less than 2 mm which is formed on an outside of the steel portion. A chemical composition of the steel for the carburizing and the steel portion of the carburized steel component satisfies simultaneously equations of a hardness parameter, a hardenability parameter, and an AlN precipitation parameter.
    Type: Grant
    Filed: June 14, 2017
    Date of Patent: August 27, 2019
    Assignee: NIPPON STEEL CORPORATION
    Inventor: Manabu Kubota
  • Patent number: 10392707
    Abstract: A steel for a carburizing and a carburized steel component having a steel portion and a carburized layer with a thickness of more than 0.4 mm to less than 2 mm which is formed on an outside of the steel portion. A chemical composition of the steel for the carburizing and the steel portion of the carburized steel component satisfies simultaneously equations of a hardness parameter, a hardenability parameter, and a TiC precipitation parameter.
    Type: Grant
    Filed: June 16, 2017
    Date of Patent: August 27, 2019
    Assignee: NIPPON STEEL CORPORATION
    Inventor: Manabu Kubota
  • Publication number: 20190256957
    Abstract: A steel according to an aspect of the present invention includes, as a chemical composition, by unit mass %, C: 0.15% to 0.40%, Mn: 0.10% to 1.50%, S: 0.002% to 0.020%, Ti: 0.005% to 0.050%, B: 0.0005% to 0.0050%, Bi: 0.0010% to 0.0100%, P: 0.020% or less, N: 0.0100% or less, Si: 0% or more and less than 0.30%, Cr: 0% to 1.50%, Al: 0% to 0.050%, Mo: 0% to 0.20%, Cu: 0% to 0.20%, Ni: 0% to 0.20%, Nb: 0% to 0.030%, and a remainder including Fe and impurities.
    Type: Application
    Filed: September 28, 2016
    Publication date: August 22, 2019
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Manabu KUBOTA, Akira SHIGA, Hajime HASEGAWA
  • Patent number: 10344363
    Abstract: There is a hot-rolled steel according to one aspect of the invention including predetermined chemical compositions including 0.0001 to 0.0050 mass % of Bi, in which 90 area % or more of a metallographic structure is configured with a ferrite and a pearlite, and an average number density of Mn sulfides extending along a rolling direction and having an aspect ratio exceeding 10 and equal to or smaller than 30, which is measured on a cross section parallel to the rolling direction, is 50 to 200 number/mm2.
    Type: Grant
    Filed: October 19, 2016
    Date of Patent: July 9, 2019
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Suguru Yoshida, Shinya Teramoto, Akira Shiga, Manabu Kubota, Hajime Hasegawa, Hideo Mizukami
  • Publication number: 20190078171
    Abstract: In this steel component, the concentration of C in a surface layer is 0.85 mass % or more to 1.2 mass % or less, which is higher than the concentration of C in a starting material steel, the surface layer has a volume ratio of a retained-austenite structure higher than 0% and lower than 10%, the remainder of the surface layer is a martensitic structure, the area fraction of grain boundary carbides in the surface layer is lower than 2%, a layer inside the surface layer is higher than the surface layer in a volume ratio of a retained-austenite structure, and in the layer inside the surface layer, the remainder is a martensitic structure.
    Type: Application
    Filed: March 8, 2017
    Publication date: March 14, 2019
    Applicants: AISIN AW CO., LTD., NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Koji OBAYASHI, Kazuaki OKADA, Keisuke MATSUZAKA, Masashi SAKAKIBARA, Manabu KUBOTA, Kei MIYANISHI, Tatsuya KOYAMA
  • Patent number: 10202677
    Abstract: A production method of a carburized steel, which improves a gas carburizing property of a steel having a high Si content and suppress deterioration of productivity, includes preliminary and main gas carburizing processes. In the preliminary gas carburizing process, a steel having a chemical composition that contains C, Si, Mn, and Cr and, in mass %, satisfies Formula (1) is subjected to a gas carburizing treatment at a carburizing temperature Tp° C. that satisfies Formula (A) for 10 minutes to less than 20 hours. In the main gas carburizing process, a gas carburizing treatment is performed at a carburizing temperature Tr(° C.) that satisfies Formula (B) for a carburizing time tr minutes. 6.5<3.5[Si %]+[Mn %]+3[Cr %]?18??(1) 800?Tp<163×ln(CP+0.6)?41×ln(3.5×[Si %]+[Mn %]+3×[Cr %])+950??(A) 4<13340/(Tr+273.15)?ln(tr)<7??(B) Where, CP in the formula is substituted by a carbon potential during carburization in the preliminary carburizing process.
    Type: Grant
    Filed: December 24, 2014
    Date of Patent: February 12, 2019
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Tatsuya Koyama, Manabu Kubota
  • Patent number: 10196720
    Abstract: Steel for nitrocarburizing includes, by mass %, C: 0% to less than 0.15%; Si: 0.01% to 1.00%; Mn: 0.01% to 1.00%; S: 0.0001% to 0.050%; Al: 0.0001% to 0.050%; Ti: more than 0.50% to 1.50%; N: 0.0005% to 0.0100%; and the balance consisting of Fe and inevitable impurities, in which P is limited to 0.050% or less; O is limited to 0.0060% or less; and the amount of Ti [Ti %], the amount of C [C %], the amount of N [N %], and the amount of S [S %] satisfy 0.48<[Ti %]?47.9×([C %]/12+[N %]/14+[S %]/32)?1.20.
    Type: Grant
    Filed: February 10, 2016
    Date of Patent: February 5, 2019
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventor: Manabu Kubota
  • Publication number: 20180371603
    Abstract: A steel according to an aspect of the present invention has a chemical composition within a predetermined range, in which a hardenability index Ceq ranges from greater than 7.5 to smaller than 44.0, a metallographic structure includes ferrite ranging from 85 to 100 area %, an average distance between sulfides, which are observed in a cross section parallel to a rolling direction of the steel and have an equivalent circle diameter ranging from 1 ?m or greater to smaller than 2 ?m, is shorter than 30.0 ?m, and a presence density of the sulfides, which are observed in the cross section parallel to the rolling direction of the steel and have an equivalent circle diameter ranging from 1 ?m or greater to smaller than 2 ?m, is 300 pieces/mm2 or more.
    Type: Application
    Filed: November 25, 2016
    Publication date: December 27, 2018
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Akira SHIGA, Manabu KUBOTA, Hajime HASEGAWA, Hideo MIZUKAMI