Patents by Inventor Yoshitaka Kojima

Yoshitaka Kojima 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).

  • Patent number: 6521293
    Abstract: A ceramic-coated blade of a gas turbine and a method of producing the same, in which the thickening of an Al2O3 layer at the interface between a ceramic layer and a primary layer is sufficiently prevented for a long period of time, thereby positively suppressing the separation of the ceramic layer. Using powder of MCrAlY alloy (Co—32%Ni—21%Cr—8%Al—0.5%Y), a primary layer (alloy coating layer) is formed on a surface of a substrate made of a heat-resistant Ni base alloy (Rene'-80). Further, a heat-resistant ceramic layer, comprising a mixture of ion-conductive ZrO2—8wt. %Y2O3 ceramic and insulative ceramic (e.g. Al2O3), is formed on the alloy coating layer. This mixture has a columnar structure in which columnar crystals are grown by a gas phase in a direction of a thickness of the coating, or a porous structure in which flattened particles brought about from molten particles caused to fly at high velocity are laminated.
    Type: Grant
    Filed: February 23, 2000
    Date of Patent: February 18, 2003
    Assignees: Hitachi, Ltd., The Tokyo Electric Power Co.
    Inventors: Yoshitaka Kojima, Hideyuki Arikawa, Mitsuo Haginoya, Katsuo Wada, Ryuta Watanabe, Yoshiaki Matsushita, Shin Yoshino
  • Patent number: 6452101
    Abstract: An object of the invention is to provide a multi-core conductive wire having the small number of manufacturing processes and a terminal with high strength, and a method of manufacturing the multi-core conductive wire. The multi-core conductive wire is provided with a terminal, at the end portion thereof, where individual strands of the multi-core conductive wire are entangled with each other and the terminal is molded by subjecting to pressure-molding. A method of manufacturing a multi-core conductive wire comprises a step of processing the multi-core conductive wire into a state where individual strands of the multi-core conductive wire are partially entangled with each other; a step of temporarily molding the processed portion; and a step of further applying pressure to the temporarily molded portion for pressure-molding or plastic working.
    Type: Grant
    Filed: February 4, 2000
    Date of Patent: September 17, 2002
    Assignee: Hitachi, Ltd.
    Inventors: Takashi Haramaki, Izumi Sakurai, Yoshitaka Kojima
  • Patent number: 6248969
    Abstract: Disclosed is a vacuum circuit breaker including a small-sized electrode structure capable of reducing deformation with age thereby enhancing the reliability and a vacuum bulb and a vacuum bulb electrode used for the breaker. In the vacuum circuit breaker, each of a fixed electrode and a movable side electrode includes an arc electrode made from particles of a refractory metal material, a high conductive metal material and a low melting point metal; an electrode supporting portion, made from the high conductive metal material, for supporting the arc electrode; a back conductor having a diameter smaller than the electrode supporting portion; and an external side connecting portion having a diameter larger than that of the back conductor. The arc electrode is integrated with the electrode supporting portion, back conductor, and external side connecting portion by the high conductive metal material, preferably, by melting of the highly conductive metal material.
    Type: Grant
    Filed: September 17, 1998
    Date of Patent: June 19, 2001
    Assignee: Hitachi, Ltd.
    Inventors: Katsuhiro Komuro, Yoshitaka Kojima, Noboru Baba, Ryo Hiraga, Toru Tanimizu, Yoshimi Hakamata, Katsumi Kuroda, Hitoshi Okabe, Shigeru Kikuchi
  • Patent number: 6048216
    Abstract: According to the present invention there are provided a highly reliable electrode of high strength which undergoes little change even with the lapse of time, and a method for making the same, as well as a vacuum valve using such electrode and a vacuum circuit breaker using such vacuum valve. The vacuum circuit breaker has a fixed electrode and a movable electrode, each comprising an arc electrode, an arc electrode support member for supporting the arc electrode, and a coil electrode contiguous to the arc electrode support member, the arc electrode, the arc electrode support member and the coil electrode being formed as an integral structure by melting, not by bonding, particularly the arc electrode support member and the coil electrode being constituted by a Cu alloy containing 0.05-2.5% by weight of at least one of Cr, Ag, W, V and Zr.
    Type: Grant
    Filed: October 5, 1998
    Date of Patent: April 11, 2000
    Assignee: Hitachi, Ltd.
    Inventors: Katsuhiro Komuro, Yoshitaka Kojima, Yukio Kurosawa, Yoshio Koguchi, Toru Tanimizu, Yoshimi Hakamata, Shunkichi Endo
  • Patent number: 6042951
    Abstract: A ceramic-coated blade of a gas turbine and a method of producing the same, in which the thickening of an Al.sub.2 O.sub.3 layer at the interface between a ceramic layer and a primary layer is sufficiently prevented for a long period of time, thereby positively suppressing the separation of the ceramic layer. Using powder of MCrAlY alloy (Co-32% Ni-21% Cr-8% Al-0.5% Y), a primary layer (alloy coating layer) is formed on a surface of a substrate made of a heat-resistant Ni base alloy (Rene'-80). Further, a heat-resistant ceramic layer, comprising a mixture of ion-conductive ZrO.sub.2 -8 wt. % Y.sub.2 O.sub.3 ceramic and insulative ceramic (e.g. Al.sub.2 O.sub.3), is formed on the alloy coating layer. This mixture has a columnar structure in which columnar crystals are grown by a gas phase in a direction of a thickness of the coating, or a porous structure in which flattened particles brought about from molten particles caused to fly at high velocity are laminated.
    Type: Grant
    Filed: February 2, 1998
    Date of Patent: March 28, 2000
    Assignees: Hitachi, Ltd., The Tokyo Electric Power Co., Inc.
    Inventors: Yoshitaka Kojima, Hideyuki Arikawa, Mitsuo Haginoya, Katsuo Wada, Ryuta Watanabe, Yoshiaki Matsushita, Shin Yoshino
  • Patent number: 5852266
    Abstract: According to the present invention there are provided a highly reliable electrode of high strength which undergoes little change even with the lapse of time, and a method for making the same, as well as a vacuum valve using such electrode and a vacuum circuit breaker using such vacuum valve. The vacuum circuit breaker has a fixed electrode and a movable electrode, each comprising an arc electrode, an arc electrode support member for supporting the arc electrode, and a coil electrode contiguous to the arc electrode support member, the arc electrode, the arc electrode support member and the coil electrode being formed as an integral structure by melting, not by bonding, particularly the arc electrode support member and the coil electrode being constituted by a Cu alloy containing 0.05-2.5% by weight of at least one of Cr, Ag, W, V and Zr.
    Type: Grant
    Filed: May 5, 1997
    Date of Patent: December 22, 1998
    Assignee: Hitachi, Ltd.
    Inventors: Katsuhiro Komuro, Yoshitaka Kojima, Yukio Kurosawa, Yoshio Koguchi, Toru Tanimizu, Yoshimi Hakamata, Shunkichi Endo
  • Patent number: 5840434
    Abstract: A ceramic coated heat-resistant element comprises a heat resisting alloy base mainly composed of Ni and/or Co and a heat-resistant coating layer provided on the surface of the base and is characterized in that said heat-resistant coating layer comprises a metal layer of an alloy superior to the base in high-temperature corrosion and oxidation resistance and provided on the base, an Al.sub.2 O.sub.3 ceramic thin film layer provided on the metal layer, a ZrO.sub.2 ceramic coating layer having dense texture provided on the Al.sub.2 O.sub.3 ceramic thin film layer and a ZrO.sub.2 ceramic coating layer having columnar texture provided on the ZrO.sub.2 ceramic coating layer having dense texture cracks are present only in the ZrO.sub.2 ceramic coating layer having columnar texture in the direction of thickness along the boundary of the columns. A mixed layer composed of a metal superior to the base in high-temperature corrosion and oxidation resistance and a ZrO.sub.
    Type: Grant
    Filed: May 2, 1996
    Date of Patent: November 24, 1998
    Assignee: Hitachi, Ltd.
    Inventors: Yoshitaka Kojima, Hideyuki Arikawa, Mitsuo Haginoya, Akira Mebata, Tetsuo Sasada, Hajime Toriya
  • Patent number: 5756130
    Abstract: There is provided a stamper for producing a recording medium exhibiting excellent durability and capable of stably forming projections and pits and a method of producing the stamper. A stamper for producing a recording medium comprising projections and pits in a predetermined pattern on the surface thereof, wherein a value of tan .theta..sup.-1 obtainable from an enlargement angle .theta. of an output from a cartridge with respect to an enlargement of an output denoting a load measured by a test of scratching the surface having the projections and pits under conditions that a diameter of a stylus is 100 .mu.m and a loading speed of 1 .mu.m/second is 1.3 or more.
    Type: Grant
    Filed: May 17, 1994
    Date of Patent: May 26, 1998
    Assignees: Hitaci Maxell, Ltd., Hitachi, Ltd.
    Inventors: Nobuhiro Umebayashi, Hiroshi Obara, Hiroshi Ishihama, Yoshitaka Kojima, Shoichi Nakashima, Shizuka Yamaguchi
  • Patent number: 5697150
    Abstract: According to the present invention there are provided a highly reliable electrode of high strength which undergoes little change even with the lapse of time, and a method for making the same, as well as a vacuum valve using such electrode and a vacuum circuit breaker using such vacuum valve. The vacuum circuit breaker has a fixed electrode and a movable electrode, each comprising an arc electrode, an arc electrode support member for supporting the arc electrode, and a coil electrode contiguous to the arc electrode support member, the arc electrode, the arc electrode support member and the coil electrode being formed as an integral structure by melting, not by bonding, particularly the arc electrode support member and the coil electrode being constituted by a Cu alloy containing 0.05-2.5% by weight of at least one of Cr, Ag, W, V and Zr.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: December 16, 1997
    Assignee: Hitachi, Ltd.
    Inventors: Katsuhiro Komuro, Yoshitaka Kojima, Yukio Kurosawa, Yoshio Koguchi, Toru Tanimizu, Yoshimi Hakamata, Shunkichi Endo
  • Patent number: 5691521
    Abstract: A vacuum switch having a fixed side electrode unit and a movable side electrode unit mounted in a vacuum vessel. Each electrode unit includes an arc electrode, an arc electrode supporting member for supporting the arc electrode, a coil electrode and a conducting rod. Joining portions between the arc electrode and the arc electrode supporting member, the coil electrode and the conducting rod are integrally and directly formed metallurgically by solid phase diffusion using a hot isostatic process. A vacuum circuit breaker may be constructed incorporating the vacuum switch.
    Type: Grant
    Filed: April 10, 1995
    Date of Patent: November 25, 1997
    Assignee: Hitachi, Ltd.
    Inventors: Katsuhiro Komuro, Yoshitaka Kojima, Yukio Kurosawa, Shunkichi Endoo, Tooru Tanimizu, Yoshimi Hakamata, Katsumi Kuroda
  • Patent number: 5630314
    Abstract: The present invention provides ceramic coated heat-resistant elements which suffer no damages even under high heat load conditions and can afford a thermal barrier effect stably for a long period of time and can be used, for example, as buckets and stationary blades of turbines. A method for making the elements is also provided. The ceramic coated heat-resistant element comprises a heat resisting alloy base mainly composed of Ni and/or Co and a heat-resistant coating layer provided on the surface of the base and is characterized in that said heat-resistant coating layer comprises a metal layer of an alloy superior to the base in high-temperature corrosion and oxidation resistance and provided on the base, an Al.sub.2 O.sub.3 ceramic thin film layer provided on the metal layer, a ZrO.sub.2 ceramic coating layer having dense texture provided on the Al.sub.2 O.sub.3 ceramic thin film layer and a ZrO.sub.2 ceramic coating layer having columnar texture provided on the ZrO.sub.
    Type: Grant
    Filed: October 11, 1994
    Date of Patent: May 20, 1997
    Assignee: Hitachi, Ltd.
    Inventors: Yoshitaka Kojima, Hideyuki Arikawa, Mitsuo Haginoya, Akira Mebata, Tetsuo Sasada, Hajime Toriya
  • Patent number: 5557083
    Abstract: According to the present invention there are provided a highly reliable electrode of high strength which undergoes little change even with the lapse of time, and a method for making the same, as well as a vacuum valve using such electrode and a vacuum circuit breaker using such vacuum valve. The vacuum circuit breaker has a fixed electrode and a movable electrode, each comprising an arc electrode, an arc electrode support member for supporting the arc electrode, and a coil electrode contiguous to the arc electrode support member, the arc electrode, the arc electrode support member and the coil electrode being formed as an integral structure by melting, not by bonding, particularly the arc electrode support member and the coil electrode being constituted by a Cu alloy containing 0.05-2.5% by weight of at least one of Cr, Ag, W, V and Zr.
    Type: Grant
    Filed: June 27, 1994
    Date of Patent: September 17, 1996
    Assignee: Hitachi, Ltd.
    Inventors: Katsuhiro Komuro, Yoshitaka Kojima, Yukio Kurosawa, Yoshio Koguchi, Toru Tanimizu, Yoshimi Hakamata, Shunkichi Endo
  • Patent number: 5545484
    Abstract: A heat and oxidation resistive high strength material utilized in structural body parts subject to bleaching in high temperature/oxidative atmosphere, the body structure of a space vehicle, a combustor, the combustor for a gas turbine, a turbine blade, and a turbine nozzle, is presented. A method for producing this heat and oxidation resistive high strength material is also explained.
    Type: Grant
    Filed: December 8, 1994
    Date of Patent: August 13, 1996
    Assignee: Hitachi, Ltd.
    Inventors: Shizuka Yamaguchi, Yoshitaka Kojima, Sai Ogawa, Hideyuki Arikawa, Mitsuo Haginoya, Yukihiko Wada, Kyozo Iwao
  • Patent number: 5507623
    Abstract: A coated layer of this invention is composed of a lower alloy-coated layer 2 formed of an MCrAlY alloy whose principal element is Co or Co and Ni, an upper alloy-coated layer 1 formed of an MCrAlY alloy whose principal element is Ni and a portion 4 in which an Al content of the surface portion of the upper coated layer 1 is largest and is reduced gradually towards a more internal part. Manufacturing thereof involves the steps of forming the lower and upper coated layers and effecting an Al diffusion treatment into the upper coated layer. The upper coated layer having the portion which exhibits the large Al content contributes to a high-temperature anticorrosive property. A gas turbine blade is provided with the alloy-coated layer, wherein the lower coated layer incorporates a composite function to prevent a high-temperature corrosion of a base material when cracks are caused in the upper coated layer due to thermal stress.
    Type: Grant
    Filed: April 4, 1994
    Date of Patent: April 16, 1996
    Assignee: Hitachi, Ltd.
    Inventors: Yoshitaka Kojima, Kiyoshi Otake, Akira Mebata, Hideyuki Arikawa, Tetsuo Sasada, Hajime Toriya
  • Patent number: 5242264
    Abstract: The disclosure is concerned with a thermal land machine which comprises a heat resistant wall for confining a chamber; a heat resistant composite structure disposed in the chamber and in contact with a hot flowing gas; and an apparatus for introducing the hot gas toward the surface of the composite structure. The composite structure including a heat resistant substrate and a continuous refractory coating formed on the substrate and made of a ceramic material. The refractory coating includes at least two layers in a laminated structure each having fine cracks substantially extended in the direction of the thickness of each of the layers and filled with a refractory material in such a manner that the filled cracks in one layer are disconnected with the filled cracks in the adjacent layer. Therefore, the hot gas cannot permeate into the surface of the substrate.
    Type: Grant
    Filed: August 8, 1990
    Date of Patent: September 7, 1993
    Assignee: Hitachi, Ltd.
    Inventors: Yoshitaka Kojima, Noriyuki Ohnaka, Shizuka Yamaguchi, Shoichi Nakashima, Sai Ogawa, Masayuki Doi, Seishin Kirihara
  • Patent number: 5209645
    Abstract: A gas turbine bucket and a gas turbine nozzle applied with a ceramic coating comprises a base material of the bucket and the nozzle made of a heat resisting alloy; a plurality of coating layers for the front portion consisting of, a mixture layer which comprises a ceramic material and metal and which is formed on the base material, an alloy layer which comprises an alloy material exhibiting excellent resistance to high temperature oxidation and corrosion and which is formed on the mixture layer, and a ceramic layer which comprises ceramic material and formed on the alloy layer. Such ceramic coating has a satisfactory thermal barrier effect on the base material of the gas turbine bucket and nozzle.
    Type: Grant
    Filed: June 15, 1990
    Date of Patent: May 11, 1993
    Assignees: Hitachi, Ltd., The Tokyo Electric Power Company, Ltd.
    Inventors: Yoshitaka Kojima, Akira Mebata, Noriyuki Ohnaka, Akihiko Chiba, Ryoichiro Ohoshima, Norio Watanabe, Yukiyoshi Hara
  • Patent number: 5203984
    Abstract: A plant operational status monitoring supervisory system comprising; means for extracting information directly relating to water quality of an objective portion consecutively for a period of time by means of an electrochemical water quality sensor installed in an objective portion to monitor in-situ in a plant; means for evaluating water quality based on thus extracted information; means for comparing an obtained water quality evaluation result with a reference value for a predetermined plant operation procedure; and means for displaying or storing necessary portion out of said comparison results; is disclosed.
    Type: Grant
    Filed: August 28, 1990
    Date of Patent: April 20, 1993
    Assignee: Hitachi, Ltd.
    Inventors: Masanori Sakai, Katsumi Mabuchi, Toshiaki Arato, Takuya Takahashi, Masakiyo Izumiya, Isao Masaoka, Yoshitaka Kojima, Masahisa Inagaki, Katsumi Ohsumi, Makoto Hayashi, Fumio Sato, Masateru Suwa, Kimihiko Akahori
  • Patent number: 5009070
    Abstract: A surface, of an inner sleeve of a combustion apparatus for a gas turbine, which is subjected to a flame radiation heat is coated with a ceramic coating. A coating which is superior in high temperature corrosion resistant characteristics to a metal material forming the inner sleeve is provided on the opposite surface of the inner sleeve. Thus, heat transferred to the inner sleeve by the radiation from the flame is shielded by the ceramic coating. A formation of oxides on the coating of the corrosion resistant metal material formed on the opposite surface of the sleeve is prevented. A heat release through the surface from the metal material forming the inner sleeve is enhanced, whereby a thermal stress generated in the inner sleeve is suppressed to thereby prevent a generation of a cracks.
    Type: Grant
    Filed: April 9, 1987
    Date of Patent: April 23, 1991
    Assignee: Hitachi, Ltd.
    Inventors: Nobuyuki Iizuka, Fumiyuki Hirose, Naotatsu Asahi, Yoshitaka Kojima
  • Patent number: 4966820
    Abstract: A ceramic-coated heat resisting alloy member comprises a base metal mainly composed of at least one of nickel, cobalt and iron; a mixture layer which is deposited on the external surface of the base metal and which comprises a ceramics and a metal; an alloy layer which is formed between the mixture layer and a ceramic coating layer formed as an outermost layer and which comprises an alloy material exhibiting excellent resistance to high temperature oxidation and excellent resistance to high temperature corrosion. It is therefore possible to prevent any high temperature oxidation and high temperature corrosion of the mixture layer and to enable the mixture layer to have a satisfactory function of reducing the thermal stress produced between the ceramic coating layer and the base metal. The ceramic coating thus has a satisfactory thermal barrier effect on the base metal.
    Type: Grant
    Filed: May 3, 1989
    Date of Patent: October 30, 1990
    Assignees: Hitachi, Ltd., The Tokyo Electric Power Company
    Inventors: Yoshitaka Kojima, Akira Mebata, Akihiko Chiba, Ryoichiro Ohoshima, Norio Watanabe, Yukiyoshi Hara
  • Patent number: 4873150
    Abstract: A wear-resistant metal member comprises a surface that has a sprayed layer consisting essentially of, by weight, 2 to 10% C, 18 to 60% Cr, 0.3 to 20% V, 25% or less Mo, 25% or less W, 10% or less Nb, 10% or less Ti, 10% or less Zr, 10% or less Hf and the balance being Fe in a proportion of 20% or greater. The sprayed layer has a martensite-phase matrix containing carbide particles, nitride particles or carbonitride particles. In addition, the member of the present invention is produced by the steps of: plasma-spraying the above-described metal in a reduced pressure atmosphere; and quenching the thus-sprayed metal layer from a predetermined temperature to form a materisite phase in that layer. In addition, the sprayed metal layer may be subjected to carburizing, nitriding or carbonitriding to form a carburized, nitrided or carbonitrided layer in the sprayed metal layer.
    Type: Grant
    Filed: October 26, 1987
    Date of Patent: October 10, 1989
    Assignee: Hitachi, Ltd.
    Inventors: Masayuki Doi, Naotatsu Asahi, Yoshitaka Kojima, Hisanobu Kanamaru, Susumu Aoyama