Patents by Inventor Kiyoshi Kojima

Kiyoshi 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).

  • Anisotropic neodymium-iron-boron system plastic bonded magnet
    Patent number: 5213703
    Abstract: This invention relates to an anisotropic neodymium-iron-boron system plastic bonded magnet containing from 10 to 20% by weight an anisotropic neodymium-iron boron system magnetic powder having a grain-size distribution from 10 to 49 microns and a resin binder. By employing this constitution, a substantially improved (BH).sub.max of the compressed mold body, due to improved magnetic field orientation, is realized.
    Type: Grant
    Filed: May 27, 1992
    Date of Patent: May 25, 1993
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Shizuo Furuyama, Kiyoshi Kojima
  • Mn--Al--C Alloys for anisotropic permanent magnets
    Patent number: 4443276
    Abstract: A permanent magnetic alloy characterized in that phosphorus of 0.6% or less by weight is added with respect to an Mn--Al--C alloy of 100% by weight comprising manganese of 68.0% to 73.0% by weight, carbon of (1/10)Mn--6.6)% to (1/3Mn--22.2)% by weight, and the remainder aluminum.
    Type: Grant
    Filed: December 28, 1982
    Date of Patent: April 17, 1984
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Susumu Sanai, Kiyoshi Kojima
  • Permanent magnetic Mn-Al-C alloy
    Patent number: 4133703
    Abstract: A permanent magnetic alloy which is obtained by adding copper in amount of 0.5 to 6.2 wt% to the conventional Mn-Al-C alloy comprising 68.0 to 73.0 wt% of manganese, (1/10 Mn -- 6.6) to (1/3 Mn -- 22.2) wt% of carbon and the remainder aluminum and subjecting thus prepared alloy to warm plastic deformation in order to improve plasticity of the alloy.
    Type: Grant
    Filed: August 17, 1977
    Date of Patent: January 9, 1979
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Shigeru Kojima, Kiyoshi Kojima, Satoru Mitani
  • 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
  • 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
  • Method of making permanent magnets of Mn-Al-C alloy
    Patent number: 3944445
    Abstract: A method of making isotropic Mn-Al-C alloy magnets which comprises the step of subjecting an alloy comprising 71.0% 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 to plastic deformation at a temperature of 550.degree.C to 780.degree.C.By utilizing this method, it is possible to obtain isotropic Mn-Al-C alloy magnets having excellent magnetic characteristics, i.e. (BH)max = 2.0 .times. 10.sup.6 G. Oe or more.
    Type: Grant
    Filed: October 8, 1974
    Date of Patent: March 16, 1976
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Tadoa Ohtani, Nobuyuki Kato, Shigeru Kojima, Yoichi Sakamoto, Masaharu Tsukahara, Kiyoshi Kojima, Isago Konno, Takao Kubo