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: 4777396
    Abstract: A rotor of induction motor comprises a rotary shaft, a cylindrical rotor core fixedly secured on the rotary shaft, a conductive cover fixed on the outer circumferential surface of the rotor core, the conductive cover being formed of a composite material of magnetic material and electrically highly conductive material to have a circumferential permeability smaller than a radial permeability, and a magnetic skin made of a magnetic material and provided on the outer circumferential surface of the conductive cover, the magnetic skin having a circumferential permeability and an electrical conductivity which are set to be larger than the circumferential permeability and an electrical resistivity of the conductive cover, respectively, whereby a loss due to a spatial higher harmonics magnetic flux of higher order generated by a pulsating magnetic flux of slots in a stator of induction motor can be prevented.
    Type: Grant
    Filed: October 23, 1987
    Date of Patent: October 11, 1988
    Assignee: Hitachi, Ltd.
    Inventors: Motoya Ito, Keiji Arai, Noriyoshi Takahashi, Noboru Fujimoto, Yoshitaka Kojima
  • Patent number: 4486462
    Abstract: A gaseous compound of a metal species or a semi-metal species is reacted with another gaseous substance capable of reacting with the gaseous compound of the metal or semi-metal species under a total pressure of not more than 10 Torr, where the partial pressure of the gaseous compound is not more than that of the gaseous substance, the reacting being carried out by the glow discharge generated between an electroconductive workpiece connected to a cathode, at least one secondary cathode provided at a position near enough to the workpiece to generate interactions of glow discharge between at least selected portions of the workpiece and the at least one secondary cathode, and an anode, thereby coating the at least selected portions of the workpiece with the resulting reaction product containing the metal or semi-metal species.
    Type: Grant
    Filed: May 12, 1982
    Date of Patent: December 4, 1984
    Assignee: Hitachi, Ltd.
    Inventors: Naotatsu Asahi, Shizuka Yamaguchi, Yoshitaka Kojima, Katsuyoshi Terakado