Patents by Inventor Sachihiro Isogawa

Sachihiro Isogawa 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: 7730755
    Abstract: The present invention relates to a process of producing a permanent magnet, which includes extruding a preform to form a plate-shaped permanent magnet, in which the preform is extruded in such a way that a dimension of a cross section of the preform is reduced in an X-direction and enlarged in a Y-direction perpendicular to the X-direction. The present invention also relates to a plate-shaped permanent magnet formed by extruding a preform, in which the preform is extruded in such a way that a dimension of a cross section of the preform is reduced in an X-direction and enlarged in a Y-direction perpendicular to the X-direction, whereby the permanent magnet has a strain ratio ?2/?1 with respect to the preform in a range of 0.2 to 3.5, in which ?1 is a strain in the direction of the extrusion of the preform and ?2 is a strain in the Y-direction.
    Type: Grant
    Filed: August 31, 2007
    Date of Patent: June 8, 2010
    Assignee: Daido Tokushuko Kabushiki Kaisha
    Inventors: Junichi Esaki, Hiroaki Yoshida, Sachihiro Isogawa
  • Publication number: 20080055031
    Abstract: The present invention relates to a process of producing a permanent magnet, which includes extruding a preform to form a plate-shaped permanent magnet, in which the preform is extruded in such a way that a dimension of a cross section of the preform is reduced in an X-direction and enlarged in a Y-direction perpendicular to the X-direction. The present invention also relates to a plate-shaped permanent magnet formed by extruding a preform, in which the preform is extruded in such a way that a dimension of a cross section of the preform is reduced in an X-direction and enlarged in a Y-direction perpendicular to the X-direction, whereby the permanent magnet has a strain ratio ?2/?1 with respect to the preform in a range of 0.2 to 3.5, in which ?1 is a strain in the direction of the extrusion of the preform and ?2 is a strain in the Y-direction.
    Type: Application
    Filed: August 31, 2007
    Publication date: March 6, 2008
    Applicant: DAIDO TOKUSHUKO KABUSHIKI KAISHA
    Inventors: Junichi Esaki, Hiroaki Yoshida, Sachihiro Isogawa
  • Patent number: 7325434
    Abstract: A method for manufacturing a ring-shaped magnet includes arranging, in a penetrating hole formed in a die, a mandrel having a cylinder tip portion of a diameter d1, a cylinder base end portion of a diameter d2, provided d1<d2, and a taper portion positioned between the cylinder tip portion and the cylinder base end portion. The penetrating hole includes a first penetrating hole portion of a diameter D1, a second penetrating hole portion of a diameter D2, provided D1<D2, and a tapered hole portion of a positioned between the first penetrating hole portion and the second penetrating hole portion. The cylinder tip portion is loaded with a preform, and plastic-working is performed on the preform in a gap formed by the penetrating hole and the mandrel by pressing the preform with a pressing punch.
    Type: Grant
    Filed: August 31, 2005
    Date of Patent: February 5, 2008
    Assignee: Daido Tokushuko Kabushiki Kaisha
    Inventors: Junichi Esaki, Sachihiro Isogawa, Takashi Sako
  • Publication number: 20060042342
    Abstract: A method for manufacturing a ring-shaped magnet material, the method comprising: in a penetrating hole formed in a die, arranging a mandrel having a cylinder tip portion of a diameter d1, a cylinder base end portion of a diameter d2 (provided d1<d2), and a taper portion of a taper angle ?2 positioned between the cylinder tip portion and the cylinder base end portion; loading the cylinder tip portion with a preform from which a ring-shaped magnet material is made, the preform being a circular-ring column shaped body whose inner diameter is d1; and plastic-working the preform in a gap, which the penetrating hole and the mandrel form, by pressing the preform with a pressing punch whose inner diameter is d1 and whose outer diameter is the same as that of the penetrating hole, the manufacturing method providing more freedom for design with respect to the magnetic properties and allowing the ring-shaped magnet material having excellent magnetic properties and high dimension accuracy to be manufactured continuous
    Type: Application
    Filed: August 31, 2005
    Publication date: March 2, 2006
    Applicant: DAIDO TOKUSHUKO KABUSHIKI KAISHA
    Inventors: Junichi Esaki, Sachihiro Isogawa, Takashi Sako
  • Patent number: 6478900
    Abstract: An improved method of forging a precipitation hardening type stainless steel. The method comprises the steps of soaking the precipitation hardening type stainless steel at a temperature of austenitizing range, cooling the steel to a temperature in the range of 200-700° C., preferably 400-600° C., and subjecting the steel to forging at the temperature in this range. Conventional lubricants and die cooling oils can be used without being deteriorated due to high temperature. It is preferable to forcibly cool the soaked steel to adjust the temperature of the steel at which it is forged. The forged steel is then age hardened to exhibit inherent hardness.
    Type: Grant
    Filed: July 1, 1996
    Date of Patent: November 12, 2002
    Assignee: Diado Tokushuko Kabushiki Kaisha
    Inventors: Sachihiro Isogawa, Masamichi Kawano, Katsuyoshi Sakoda
  • Patent number: 5746845
    Abstract: A high-strength member of precipitation hardening martensitic steel is manufactured through the steps of heating precipitation hardening martensitic stainless steel at an austenitizing temperature, performing the first plastic working at a temperature between 200.degree. C. and 700.degree. C. so as to leave a part of austenite as retained austenite at the time of cooling the steel at Ms point or below thereafter, cooling the steel at the temperature not higher than Ms point, performing the next plastic working at a temperature not higher than As point so as to transform the retained austenite into martensite, and performing age hardening treatment at a temperature between not lower than 370.degree. C. and lower than 480.degree. C.
    Type: Grant
    Filed: September 27, 1995
    Date of Patent: May 5, 1998
    Assignee: Daido Tokushuko Kabushiki Kaisha
    Inventors: Hiroaki Yoshida, Sachihiro Isogawa
  • Patent number: 5244517
    Abstract: A titanium alloy is prepared containing 2 to 4% by weight of aluminum, 1.5 to 2.5% by weight of vanadium, 0.20 to 0.45% by weight of a rare earth element (not essential). 0.05 to 0.11% by weight of sulfur (not essential), and titanium substantially for the remainder, the ratio of the rear earth element content to the sulfur content ranging from 3.8 to 4.2. This titanium alloy is rough-formed and hot-forged at a temperature in a .beta. region, and the resulting titanium alloy ingot is processed directly into a titanium alloy component having a desired shape. The titanium alloy component thus manufactured has a satisfactory fatigue strength and is also excellent in machinability, and can be used for connecting rods, valves, retainers, etc. to be incorporated in the engine of an automobile.
    Type: Grant
    Filed: November 15, 1991
    Date of Patent: September 14, 1993
    Assignees: Daido Tokushuko Kabushiki Kaisha, Honda Giken Kogyo Kabushiki Kaisha
    Inventors: Atsuyoshi Kimura, Sachihiro Isogawa, Toshihiko Matsubara