Patents by Inventor Tohru Obata

Tohru Obata 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).

  • Publication number: 20230040720
    Abstract: A method for manufacturing an R-T-B based sintered magnet according the present disclosure comprises: a step for preparing a coarse ground powder which is made from an alloy for R-T-B based sintered magnets and which has an average particle size of 10-500 ?m; a step for obtaining a fine powder having an average particle size of 2.0-4.5 ?m, by feeding the coarse ground powder to a jet mill device that has a grinding chamber filled with inert gas and grinding the coarse ground powder; and a step for producing a sintered body of the fine powder, wherein the inert gas has been humidified, and the oxygen content of the R-T-B based sintered magnet is 1000-3500 ppm by mass.
    Type: Application
    Filed: December 24, 2020
    Publication date: February 9, 2023
    Inventors: Nobuhiko FUJIMORI, Tohru OBATA, Kazuhiro SONODA, Futoshi KUNIYOSHI, Daisuke FURUSAWA, Tomohito MAKI, Shuji MINO, Kouta SAITOU
  • Patent number: 9721724
    Abstract: [Problem] To provide a highly efficient manufacturing method including an RH supply-diffusion process by which the number of magnets processed at a time can be increased without allowing sintered R-T-B based magnets to stick to holding members. [Solution] A method for producing a sintered R-T-B based magnet including the steps of: forming a stack of RH diffusion sources and sintered R-T-B based magnet bodies by stacking the diffusion sources and the magnet bodies alternately with a holding member having openings interposed; and carrying out an RH supply-diffusion process by loading the stack into a process vessel and creating an atmosphere with a pressure of 0.1 Pa to 50 Pa and a temperature of 800° C. to 950° C. within the process vessel.
    Type: Grant
    Filed: August 5, 2011
    Date of Patent: August 1, 2017
    Assignee: HITACHI METALS, LTD.
    Inventor: Tohru Obata
  • Publication number: 20140329007
    Abstract: A method according to the present disclosure includes the steps of: stacking RH diffusion sources and sintered R-T-B based magnet bodies alternately one upon the other with a flat plate holding member having openings interposed between each pair of the diffusion source and the magnet body, thereby forming a multilayer structure; loading the multilayer structure in a process vessel; (A) performing an RH supply-diffusion process at a pressure of 2.0 Pa to 50 Pa and at a temperature of 800° C. to 950° C. in the process vessel; and (B) performing an RH diffusion process at a pressure of 150 Pa to 2 kPa and at a temperature of 800° C. to 950° C. in the process vessel. The method includes the step of carrying out the steps (A) and (B) alternately and repeatedly at least twice.
    Type: Application
    Filed: February 28, 2013
    Publication date: November 6, 2014
    Inventor: Tohru Obata
  • Publication number: 20130181039
    Abstract: [Problem] To provide a highly efficient manufacturing method including an RH supply-diffusion process by which the number of magnets processed at a time can be increased without allowing sintered R-T-B based magnets to stick to holding members. [Solution] A method for producing a sintered R-T-B based magnet including the steps of: forming a stack of RH diffusion sources and sintered R-T-B based magnet bodies by stacking the diffusion sources and the magnet bodies alternately with a holding member having openings interposed; and carrying out an RH supply-diffusion process by loading the stack into a process vessel and creating an atmosphere with a pressure of 0.1 Pa to 50 Pa and a temperature of 800° C., to 950° C., within the process vessel.
    Type: Application
    Filed: August 5, 2011
    Publication date: July 18, 2013
    Applicant: HITACHI METALS, LTD.
    Inventor: Tohru Obata