Patents by Inventor Soichiro Ohga

Soichiro Ohga 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 for inserting balls and spacers into ball screw device
    Patent number: 6643932
    Abstract: A ball screw device utilizes spacers having concave ball-contacting surfaces with distributed protrusions or dimples. Balls having needle-like recesses may also be used. The spacers are provided in two thicknesses, and the relative numbers of the thinner and thicker spacers are selected in order to ensure retention of the spacers in their proper positions, while providing a small clearance between the balls and spacers to avoid fluctuations or sharp increases in dynamic torque.
    Type: Grant
    Filed: May 23, 2002
    Date of Patent: November 11, 2003
    Assignee: Tsubaki Nakashima Co., Ltd.
    Inventors: Hiroyuki Takagi, Hidemi Horimoto, Soichiro Ohga
  • Ball screw with alternately disposed steel balls and ceramic balls
    Patent number: 6499374
    Abstract: A ball screw comprising a screw shaft 1 made of steel and having a thread groove 6 on outer peripheral surface, a ball nut 2 made of steel and having a thread groove 7 opposing the thread groove 6 on inner peripheral surface, a return tube 3 attached on the ball nut 2, and a plurality of balls inserted between the two thread grooves 6 and 7 and in the return tube 3. As the balls, steel balls 4 made of bearing steel and ceramic balls 5 made of silicon nitride are disposed alternately at a given ratio. Diameter Dc of the ceramic ball 5 is set to a value smaller than diameter Ds of the steel ball 4 so that contact stress acted on contact surfaces of the ceramic ball 5 and the two thread grooves 6 and 7 will be equal to contact stress acted on contact surfaces of the steel ball 4 and the two thread grooves 6 and 7.
    Type: Grant
    Filed: July 30, 2001
    Date of Patent: December 31, 2002
    Assignee: Tsubaki Nakashima Co., Ltd.
    Inventor: Soichiro Ohga
  • Method for inserting balls and spacers into ball screw device
    Publication number: 20020139209
    Abstract: A ball screw device utilizes spacers having concave ball-contacting surfaces with distributed protrusions or dimples. Balls having needle-like recesses may also be used. The spacers are provided in two thicknesses, and the relative numbers of the thinner and thicker spacers are selected in order to ensure retention of the spacers in their proper positions, while providing a small clearance between the balls and spacers to avoid fluctuations or sharp increases in dynamic torque.
    Type: Application
    Filed: May 23, 2002
    Publication date: October 3, 2002
    Applicant: Tsubaki Nakashima Co., Ltd.
    Inventors: Hiroyuki Takagi, Hidemi Horimoto, Soichiro Ohga
  • Ball screw device having spacers
    Patent number: 6415676
    Abstract: A ball screw device utilizes spacers having concave ball-contacting surfaces with distributed protrusions or dimples. Balls having needle-like recesses may also be used. The spacers are provided in two thicknesses, and the relative numbers of the thinner and thicker spacers are selected in order to ensure retention of the spacers in their proper positions, while providing a small clearance between the balls and spacers to avoid fluctuations or sharp increases in dynamic torque.
    Type: Grant
    Filed: October 24, 2000
    Date of Patent: July 9, 2002
    Assignee: Tsubaki Nakashima Co., Ltd.
    Inventors: Hirouyki Takagi, Hidemi Horimoto, Soichiro Ohga