Patents by Inventor Koji Hirao

Koji Hirao 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: 7018722
    Abstract: The present invention provides an aluminum alloy fin material for heat exchangers which has a thickness of 80 ?m (0.08 mm) or less and excels in joinability to a tube material and in intergranular corrosion resistance. The aluminum alloy fin material is an aluminum alloy bare fin material or a brazing fin material which has a thickness of 80 ?m or less and is incorporated into a heat exchanger made of an aluminum alloy manufactured by brazing through an Al—Si alloy filler metal. The structure of the core material before brazing is a fiber structure, and the crystal grain diameter of the structure after brazing is 50–250 ?m. The Si concentration in the Si dissolution area on the surface of the fin material and at the center of the thickness of the fin material after brazing is preferably 0.8% or more and 0.7% or less, respectively.
    Type: Grant
    Filed: June 23, 2003
    Date of Patent: March 28, 2006
    Assignees: Denso Corporation, Sumitomo Light Metal Industries, Ltd.
    Inventors: Taketoshi Toyama, Koji Hirao, Takashi Hatori, Yuji Hisatomi, Yasunaga Itoh, Yoshifusa Shoji
  • Patent number: 6849136
    Abstract: An object of the present invention is to provide a filler metal for an aluminum brazing sheet for heat exchangers capable of preventing or controlling occurrence of a melting hole during heating for brazing, and a method of manufacturing the same. In an Al—Si alloy filler metal which is clad on the aluminum brazing sheet and melted during heating for brazing, the maximum particle diameter of a coarse Si particle crystallized in the eutectic structure of the filler metal is 20 ?m or less. Provided that an average value and a standard deviation in a normal distribution of the particle diameter of the coarse Si particle in the filler metal are respectively ? and ?, (?+3?) is preferably 10 ?m or less. This brazing sheet is obtained by a method of adding a specific amount of Na, Sr, or Sb to the filler metal, a method of limiting the amount of impurities in the filler metal within a specific range, a method of specifying a cooling rate during the casting of the filler metal, or the like.
    Type: Grant
    Filed: July 25, 2002
    Date of Patent: February 1, 2005
    Assignees: Denso Corporation, Sumitomo Light Metal Industries, Ltd.
    Inventors: Yoshiharu Hasegawa, Koji Hirao, Hiroshi Nishikawa, Yasunaga Itoh, Naoki Yamashita, Shinichi Tani, Keiichi Sakai, Eiichi Kashima
  • Publication number: 20040028940
    Abstract: The present invention provides an aluminum alloy fin material for heat exchangers which has a thickness of 80 &mgr;m (0.08 mm) or less and excels in joinability to a tube material and in intergranular corrosion resistance. The aluminum alloy fin material is an aluminum alloy bare fin material or a brazing fin material which has a thickness of 80 &mgr;m or less and is incorporated into a heat exchanger made of an aluminum alloy manufactured by brazing through an Al—Si alloy filler metal. The structure of the core material before brazing is a fiber structure, and the crystal grain diameter of the structure after brazing is 50-250 &mgr;m. The Si concentration in the Si dissolution area on the surface of the fin material and at the center of the thickness of the fin material after brazing is preferably 0.8% or more and 0.7% or less, respectively.
    Type: Application
    Filed: June 23, 2003
    Publication date: February 12, 2004
    Inventors: Taketoshi Toyama, Koji Hirao, Takashi Hatori, Yuji Hisatomi, Yasunaga Itoh, Yoshifusa Shoji
  • Patent number: 6625886
    Abstract: In a manufacturing method of a heat exchanger including a core portion having a plurality of tubes and a plurality of radiation fins connected to surfaces of the tubes, and a tank portion communicating with the tubes, a preheating step, a brazing step, a gradual cooling step and a cooling step are performed in this order. In the preheating step, temperature of the tank portion having a large heat capacity is increased earlier than that of the core portion having a small heat capacity. Therefore, the temperature of the tank portion is rapidly increased, and the temperature of the core portion is obediently increased in accordance with the temperature increase of the tank portion.
    Type: Grant
    Filed: June 17, 2002
    Date of Patent: September 30, 2003
    Assignee: Denso Corporation
    Inventors: Syoji Iriyama, Koji Hirao, Hiroshi Ogawa, Takanori Takeda, Hiroshi Nishikawa, Satoshi Nohira
  • Publication number: 20030051342
    Abstract: An object of the present invention is to provide a filler metal for an aluminum brazing sheet for heat exchangers capable of preventing or controlling occurrence of a melting hole during heating for brazing, and a method of manufacturing the same. In an Al—Si alloy filler metal which is clad on the aluminum brazing sheet and melted during heating for brazing, the maximum particle diameter of a coarse Si particle crystallized in the eutectic structure of the filler metal is 20 &mgr;m or less. Provided that an average value and a standard deviation in a normal distribution of the particle diameter of the coarse Si particle in the filler metal are respectively &mgr; and &sgr;, (&mgr;+3&sgr;) is preferably 10 &mgr;m or less.
    Type: Application
    Filed: July 25, 2002
    Publication date: March 20, 2003
    Inventors: Yoshiharu Hasegawa, Koji Hirao, Hiroshi Nishikawa, Yasunaga Itoh, Naoki Yamashita, Shinichi Tani, Keiichi Sakai, Eiichi Kashima
  • Publication number: 20030033715
    Abstract: In a manufacturing method of a heat exchanger including a core portion having a plurality of tubes and a plurality of radiation fins connected to surfaces of the tubes, and a tank portion communicating with the tubes, a preheating step, a brazing step, a gradual cooling step and a cooling step are performed in this order. In the preheating step, temperature of the tank portion having a large heat capacity is increased earlier than that of the core portion having a small heat capacity. Therefore, the temperature of the tank portion is rapidly increased, and the temperature of the core portion is obediently increased in accordance with the temperature increase of the tank portion.
    Type: Application
    Filed: June 17, 2002
    Publication date: February 20, 2003
    Inventors: Syoji Iriyama, Koji Hirao, Hiroshi Ogawa, Takanori Takeda, Hiroshi Nishikawa, Satoshi Nohira
  • Publication number: 20020078566
    Abstract: A manufacturing method for an evaporator made of aluminum alloy. First, a three-layer aluminum alloy plate having a core made of Al—Mn alloy, a sacrifice anode layer made of aluminum alloy which is electro-chemically base with respect to the core and clad on one side of the core, and a brazing layer made of Al—Si alloy and clad on the other side of the core is uniformly rolled to be work-hardened. Next, the thin work-hardened aluminum alloy plate is bent to form a tube so that the sacrifice anode layer is disposed outside the tube to face air and the brazing layer is disposed inside the tube to face refrigerant. Then, plural tubes and outer fins are alternately laminated and are integrally brazed to tanks to form the evaporator. As a result, a thickness of the tube is reduced without deteriorating corrosion resistance of the tube, thereby decreasing a weight and a size of the evaporator.
    Type: Application
    Filed: December 21, 2001
    Publication date: June 27, 2002
    Inventors: Eiichi Torigoe, Koji Hirao, Masamichi Makihara, Toshiya Nagasawa
  • Patent number: 6234377
    Abstract: A brazing composition for aluminum materials capable of functioning as a flux and a brazing material with a single component and providing a solid brazed joint exhibiting little local fusion. The brazing composition for aluminum materials which has the function of removing the oxide film on the surface of the aluminum material to be joined at a temperature lower than the melting point of the aluminum material and forming a eutectic aluminum alloy braze which fuses at such a low temperature by reaction with the aluminum materials, wherein the brazing composition comprises a first powder comprising at least one or more M—Si—F compounds comprising, in addition to at least Si and F, hydrogen or an alkaline metal or hydrates thereof or comprises this first powder as an component.
    Type: Grant
    Filed: June 30, 1999
    Date of Patent: May 22, 2001
    Assignees: Denso Corporation, Sumitomo Light Metal Industries, Ltd.
    Inventors: Shoei Teshima, Koji Hirao, Yuji Hisatomi, Hiroshi Ikeda
  • Patent number: 6129143
    Abstract: A brazing sheet which has an excellent corrosion resistance and cladding rolling property, and is formed from a four layer aluminum alloy cladding member, and a heat exchanger of aluminum alloy, in which the brazing sheet is used, are provided. The brazing sheet is suitable for use as a member in the fluid path of an aluminum heat exchange for a car, and particularly, as a core plate of a drawn cup type heat exchanger. In the brazing sheet, one side of a core member is cladded with an intermediate member less noble than a core member, and the other side of both the core member and the intermediate member are cladded with Al--Si--Mg type cladding member, wherein the core member is of an aluminum alloy containing 0.5 to 1.6% of Mn, 0.15 to 0.35% of Cu, 0.05 to 0.50% of Mg, 0.06 to 0.30% of Ti, and the remainder being Al and unavoidable impurities, and the intermediate member contains 0.5 to 1.2% of Mn and the remainder being aluminum and unavoidable impurities, and 0.05 to 1.
    Type: Grant
    Filed: August 5, 1997
    Date of Patent: October 10, 2000
    Assignees: Denso Corporation, Sumitomo Light Metal Industries, Ltd.
    Inventors: Yoshiharu Hasegawa, Haruhiko Miyachi, Yuji Suzuki, Hiroshi Ikeda, Hirokazu Tanaka, Takahiro Koyama, Koji Hirao
  • Patent number: 4337978
    Abstract: A hinge fitting mechanism especially for motor vehicle seats in which a fixed seat plate fixedly connected to the seat and a tiltable plate fixedly connected to the back rest are articulatedly connected to each other and which includes a mechanism for gradually adjusting the position of the plates relative to each other, and a quick tilting of the tiltable plate and hence the seat back connected thereto relative to the fixed seat plate connected to the actual seat portion.
    Type: Grant
    Filed: April 23, 1980
    Date of Patent: July 6, 1982
    Assignee: Aisin Seiki Kabushiki Kaisha
    Inventors: Kenichi Kazaoka, Koji Hirao, Hideki Takahasi