Patents by Inventor Hirakazu Yoshida

Hirakazu Yoshida 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).

  • Electric linear actuator
    Patent number: 9890840
    Abstract: An electric linear actuator has a housing, an electric motor, a speed reduction mechanism and a ball screw mechanism. The ball screw mechanism has a nut and screw shaft. A blind bore is formed on the housing. The blind bore contains an end of the screw shaft. An anti-rotation mechanism for the screw shaft has a sleeve and guide pin. The sleeve is press-formed from steel sheet and fit into the blind bore of the housing. The guide pin is mounted on the end of the screw shaft, via a through aperture formed in the screw shaft. The guide pin axially movably engages the sleeve.
    Type: Grant
    Filed: April 10, 2015
    Date of Patent: February 13, 2018
    Assignee: NTN Corporation
    Inventors: Takaaki Ohnishi, Kunimichi Hatano, Keisuke Kazuno, Hirakazu Yoshida
  • Ball Screw And A Method For Manufacturing The Same
    Publication number: 20160169356
    Abstract: A ball screw has a nut formed with a helical ball rolling groove on its inner circumference. A screw shaft is formed with a helical ball rolling groove on its inner circumference. The screw shaft is inserted into the nut. A number of balls are rollably contained within a ball rolling passage formed by oppositely arranged helical ball rolling grooves of the nut and the screw shaft, respectively. The nut is made of case hardened steel. The ball rolling groove is formed by cutting and surface hardening, by vacuum carburizing hardening, without any after-processing.
    Type: Application
    Filed: February 23, 2016
    Publication date: June 16, 2016
    Inventors: Koji TATEISHI, Hirakazu YOSHIDA
  • Ball screw and a method for manufacturing the same
    Patent number: 9289828
    Abstract: A ball screw has a nut formed with a helical ball rolling groove on its inner circumference. A screw shaft is formed with a helical ball rolling groove on its inner circumference. The screw shaft is inserted into the nut. A number of balls are rollably contained within a ball rolling passage formed by oppositely arranged helical ball rolling grooves of the nut and the screw shaft, respectively. The nut is made of case hardened steel. The ball rolling groove is formed by cutting and surface hardening, by vacuum carburizing hardening, without any after-processing.
    Type: Grant
    Filed: October 30, 2009
    Date of Patent: March 22, 2016
    Assignee: NTN Corporation
    Inventors: Koji Tateishi, Hirakazu Yoshida
  • Electric Linear Actuator
    Publication number: 20150285347
    Abstract: An electric linear actuator has a housing, an electric motor, a speed reduction mechanism and a ball screw mechanism. The ball screw mechanism has a nut and screw shaft. A blind bore is formed on the housing. The blind bore contains an end of the screw shaft. An anti-rotation mechanism for the screw shaft has a sleeve and guide pin. The sleeve is press-formed from steel sheet and fit into the blind bore of the housing. The guide pin is mounted on the end of the screw shaft, via a through aperture formed in the screw shaft. The guide pin axially movably engages the sleeve.
    Type: Application
    Filed: April 10, 2015
    Publication date: October 8, 2015
    Inventors: Takaaki OHNISHI, Kunimichi HATANO, Keisuke KAZUNO, Hirakazu YOSHIDA
  • Ball Screw And A Method For Manufacturing The Same
    Publication number: 20100043582
    Abstract: A ball screw has a nut formed with a helical ball rolling groove on its inner circumference. A screw shaft is formed with a helical ball rolling groove on its inner circumference. The screw shaft is inserted into the nut. A number of balls are rollably contained within a ball rolling passage formed by oppositely arranged helical ball rolling grooves of the nut and the screw shaft, respectively. The nut is made of case hardened steel. The ball rolling groove is formed by cutting and surface hardening, by vacuum carburizing hardening, without any after-processing.
    Type: Application
    Filed: October 30, 2009
    Publication date: February 25, 2010
    Applicant: NTN Corporation
    Inventors: Koji Tateishi, Hirakazu Yoshida