Patents by Inventor Tadao Ohtani

Tadao Ohtani 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).

  • Method of making permanent magnet of Mn-Al-C alloy
    Patent number: 4404046
    Abstract: There is provided a method of producing a manganese-aluminum-carbon alloy magnet, including the steps of preparing a polycrystalline Mn-Al-C alloy magnet having a specified direction of easy magnetization and subjecting the magnet to compressive working in that direction at a temperature of 550.degree. to 780.degree. C., the degree of said compressive working being equivalent to a logarithmic strain of .ltoreq.-0.1 and working in said step at least up to a logarithmic strain of -0.1 being free compression.
    Type: Grant
    Filed: February 5, 1981
    Date of Patent: September 13, 1983
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Yoichi Sakamoto, Akihiko Ibata, Shigeru Kojima, Tadao Ohtani
  • Inboard type magnetic system for electro-dynamic transducer
    Patent number: 4055732
    Abstract: An inboard type magnetic system for an electrodynamic transducer which has a reduced height and magnetic flux leakage by making use of a manganese-aluminum-carbon system alloy magnet anisotropized by warm extrusion.
    Type: Grant
    Filed: December 2, 1975
    Date of Patent: October 25, 1977
    Assignee: Matsushita Electric Industrial Company Limited
    Inventors: Hisashi Yoshimura, Sadao Yukimoto, Takashi Matsumoto, Isago Konno, Nobuyuki Kato, Tadao Ohtani, Takao Kubo
  • Method of making anisotropic permanent magnets of Mn-Al-C alloys
    Patent number: 4051706
    Abstract: Anisotropic permanent magnets of Mn-Al-C polycrystalline alloy are produced by warm extrusion at a temperature of 530.degree. to 830.degree. C utilizing converging or tapered dies with lubricant interposed between the polycrystalline body and the converging die. With dies of rather small semiangles, alloys with improved magnetic properties with regard to (BH)max, and especially Br are obtained.
    Type: Grant
    Filed: July 1, 1975
    Date of Patent: October 4, 1977
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Yoichi Sakamoto, Nobuyuki Kato, Tadao Ohtani
  • Magnetic alloys having wasp-waisted magnetic hysteresis loop
    Patent number: 4042429
    Abstract: Magnetic alloys consisting of 68.0.about.73.0 weight % manganese, (1/10 Mn - 6.6).about.(1/3 Mn - 22.2) weight % carbon, the balance aluminum, which show wasp-waisted magnetic hysteresis loops with the ratio of the residual magnetization 4.pi.I.sub.r to the intensity of magnetization 4.pi.I.sub.10000 in a magnetic field of 10000 Oe, I.sub.r /I.sub.10000, falling 0.0.about.0.2.
    Type: Grant
    Filed: October 1, 1974
    Date of Patent: August 16, 1977
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Shigeru Kojima, Kiyoshi Kojima, Tadao Ohtani, Nobuyuki Kato, Yoichi Sakamoto, Isago Konno, Masaharu Tsukahara, Takao Kubo
  • Anisotropic permanent magnet of Mn-Al-C alloy
    Patent number: 4023991
    Abstract: An anisotropic permanent magnet of an Mn-Al-C alloy containing 68.0% to 73.0% by weight of manganese, (1/10Mn-6.6)% to (1/3Mn-22.2)% by weight of carbon, and the remainder aluminum, which alloy is rendered anisotropic by deforming it plastically at a temperature of 530.degree. to 830.degree. C.The permanent magnet has excellent mechanical characteristics and magnetic properties such that the (BH) max is above 4.8 .times. 10.sup.6 G.Oe up to about 9.2 .times. 10.sup.6 G.Oe in its bulk state.
    Type: Grant
    Filed: June 1, 1976
    Date of Patent: May 17, 1977
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Takao Kubo, Tadao Ohtani, Shigeru Kojima, Nobuyuki Kato, Kiyoshi Kojima, Yoichi Sakamoto, Isago Konno, Masaharu Tsukahara
  • Magnetron employing a permanent magnet formed of a manganese-aluminum-carbon system alloy
    Patent number: 3989979
    Abstract: A magnetron comprising means for applying a magnetic field in a direction perpendicular to an electric field established between an anode and a cathode, the magnetic field applying means including a permanent magnet formed of a manganese-aluminum-carbon system alloy and disposed within an enclosure member in which an interaction space for electrons is formed, or used as part of the enclosure member.
    Type: Grant
    Filed: July 29, 1975
    Date of Patent: November 2, 1976
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Isago Konno, Tadao Ohtani
  • Machinable anisotropic permanent magnets of Mn-Al-C alloys
    Patent number: 3976519
    Abstract: An anisotropic permanent magnet of an Mn-Al-C alloy containing 68.0% to 73.0% by weight of manganese, (1/10 Mn-6.6)% to (1/3 Mn-22.2)% by weight of carbon, and the remainder aluminum, which alloy is rendered anisotropic by deforming it plastically at a temperature of 530.degree.C to 830.degree.C.The permanent magnet has excellent mechanical characteristics and magnetic properties such that the (BH)max is above 4.8 .times. 10.sup.6 G.Oe up to about 9.2 .times. 10.sup.6 G.Oe in its bulk state.
    Type: Grant
    Filed: July 23, 1974
    Date of Patent: August 24, 1976
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Takao Kubo, Tadao Ohtani, Shigeru Kojima, Nobuyuki Kato, Kiyoshi Kojima, Yoichi Sakamoto, Isago Konno, Masaharu Tsukahara