Patents by Inventor Minoru Takao

Minoru Takao 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: 9334193
    Abstract: A wear resistant member formed of ceramic sintered body mainly composed of silicon nitride, the ceramic sintered body containing 10 to 3500 ppm of an Fe component in terms of Fe element, more than 1000 ppm to 2000 ppm of a Ca component in terms of Ca element, and 1 to 2000 ppm of a Mg component in terms of Mg element, wherein a ?-phase ratio of silicon nitride crystal grains is 95% or more, a maximum longer diameter of the silicon nitride crystal grains is 40 ?m or less, Ca component existing in grain boundary phase is not detected by XRD (X-ray Diffraction method), and each of dispersions in Vickers hardness, fracture toughness and density of the wear resistant member is within a range of ±10%. According to this structure, there can be obtained a wear resistant member comprising a ceramic sintered body improved in grinding-work property in addition to an excellent wear resistant property.
    Type: Grant
    Filed: February 10, 2011
    Date of Patent: May 10, 2016
    Assignees: KABUSHIKI KAISHA TOSHIBA, TOSHIBA MATERIALS CO., LTD.
    Inventor: Minoru Takao
  • Patent number: 8579513
    Abstract: A sliding member includes a silicon nitride sintered compact containing a rare earth element of 7 to 18 mass % in terms of oxide and at least one element M selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W of 0.1 to 3 mass % in terms of oxide, and having a total content of impurity positive ion elements of 0.3 mass % or less and a thermal conductivity of 60 W/m·K or higher. The silicon nitride sintered compact includes silicon nitride crystal grains and a grain boundary phase, and has a ratio of crystalline compound phases in the grain boundary phase of 20% or more in area ratio, and an average grain size of the crystalline compound phases of 0.5 ?m or less. The sliding member is used, for example, as a bearing ball 2.
    Type: Grant
    Filed: July 25, 2007
    Date of Patent: November 12, 2013
    Assignees: Kabushiki Kaisha Toshiba, Toshiba Materials Co., Ltd.
    Inventor: Minoru Takao
  • Patent number: 8377837
    Abstract: A wear resistant member formed of silicon nitride sintered body having a volume of 4000 mm3 or more, the silicon nitride sintered body containing 1 to 5 mass % of a rare earth component in terms of rare earth element, 1 to 6 mass % of an Al component in terms of Al element, 10 to 3500 ppm of an Fe component in terms of Fe element, and 10 to 1000 ppm of a Ca component in terms of Ca element, wherein a ?-phase ratio of silicon nitride crystal grains is 95% or more, a maximum longer diameter of the silicon nitride crystal grains is 40 ?m or less, and each of dispersions in Vickers hardness and fracture toughness of an inner portion of the wear resistant member is within a range of ±10%. According to this structure, the wear resistant member can be manufactured with a low cost, and there can be provided a wear resistant member comprising a silicon nitride sintered body excellent in reliability and the dispersion in characteristics is effectively suppressed.
    Type: Grant
    Filed: April 9, 2009
    Date of Patent: February 19, 2013
    Assignees: Kabushiki Kaisha Toshiba, Toshiba Materials Co., Ltd.
    Inventor: Minoru Takao
  • Publication number: 20120321851
    Abstract: A wear resistant member formed of ceramic sintered body mainly composed of silicon nitride, the ceramic sintered body containing 10 to 3500 ppm of an Fe component in terms of Fe element, more than 1000 ppm to 2000 ppm of a Ca component in terms of Ca element, and 1 to 2000 ppm of a Mg component in terms of Mg element, wherein a ?-phase ratio of silicon nitride crystal grains is 95% or more, a maximum longer diameter of the silicon nitride crystal grains is 40 ?m or less, Ca component existing in grain boundary phase is not detected by XRD (X-ray Diffraction method), and each of dispersions in Vickers hardness, fracture toughness and density of the wear resistant member is within a range of ±10%. According to this structure, there can be obtained a wear resistant member comprising a ceramic sintered body improved in grinding-work property in addition to an excellent wear resistant property.
    Type: Application
    Filed: February 10, 2011
    Publication date: December 20, 2012
    Applicants: TOSHIBA MATERIALS CO., LTD., KABUSHIKI KAISHA TOSHIBA
    Inventor: Minoru Takao
  • Patent number: 8133830
    Abstract: A silicon nitride sintered compact contains silicon nitride grains, and a sintering aid component in a range of 2 to 15 mass %. The silicon nitride grains include needle crystal grains each having a long diameter L of 10 ?m or less and a ratio (L/S) of the long diameter L to a short diameter S of 5 or more, by 50% or more in area ratio in a crystalline structure of the silicon nitride sintered compact. The silicon nitride sintered compact is used as a sliding member like a bearing ball (2).
    Type: Grant
    Filed: March 11, 2008
    Date of Patent: March 13, 2012
    Assignees: Kabushiki Kaisha Toshiba, Toshiba Materials Co., Ltd.
    Inventors: Minoru Takao, Michiyasu Komatsu
  • Publication number: 20110039068
    Abstract: A wear resistant member formed of silicon nitride sintered body having a volume of 4000 mm3 or more, the silicon nitride sintered body containing 1 to 5 mass % of a rare earth component in terms of rare earth element, 1 to 6 mass % of an Al component in terms of Al element, 10 to 3500 ppm of an Fe component in terms of Fe element, and 10 to 1000 ppm of a Ca component in terms of Ca element, wherein a ?-phase ratio of silicon nitride crystal grains is 95% or more, a maximum longer diameter of the silicon nitride crystal grains is 40 ?m or less, and each of dispersions in Vickers hardness and fracture toughness of an inner portion of the wear resistant member is within a range of ±10%. According to this structure, the wear resistant member can be manufactured with a low cost, and there can be provided a wear resistant member comprising a silicon nitride sintered body excellent in reliability and the dispersion in characteristics is effectively suppressed.
    Type: Application
    Filed: April 9, 2009
    Publication date: February 17, 2011
    Applicants: KABUSHIKI KAISHA TOSHIBA, TOSHIBA MATERIALS CO., LTD.
    Inventor: Minoru Takao
  • Publication number: 20100054652
    Abstract: A silicon nitride sintered compact contains silicon nitride grains, and a sintering aid component in a range of 2 to 15 mass %. The silicon nitride grains include needle crystal grains each having a long diameter L of 10 ?m or less and a ratio (L/S) of the long diameter L to a short diameter S of 5 or more, by 50% or more in area ratio in a crystalline structure of the silicon nitride sintered compact. The silicon nitride sintered compact is used as a sliding member like a bearing ball (2).
    Type: Application
    Filed: March 11, 2008
    Publication date: March 4, 2010
    Inventors: Minoru Takao, Michiyasu Komatsu
  • Publication number: 20090238508
    Abstract: A sliding member includes a silicon nitride sintered compact containing a rare earth element of 7 to 18 mass % in terms of oxide and at least one element M selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W of 0.1 to 3 mass % in terms of oxide, and having a total content of impurity positive ion elements of 0.3 mass % or less and a thermal conductivity of 60 W/m·K or higher. The silicon nitride sintered compact includes silicon nitride crystal grains and a grain boundary phase, and has a ratio of crystalline compound phases in the grain boundary phase of 20% or more in area ratio, and an average grain size of the crystalline compound phases of 0.5 ?m or less. The sliding member is used, for example, as a bearing ball 2.
    Type: Application
    Filed: July 25, 2007
    Publication date: September 24, 2009
    Inventor: Minoru Takao
  • Patent number: 7521388
    Abstract: A silicon nitride abrasion resistant member is formed of silicon nitride sintered body containing 2% to 4% by mass of a rare earth element in terms of oxide thereof as a sintering aid, 2% to 6% by mass of an Al component in terms of oxide thereof, and 2% to 7% by mass of silicon carbide. The silicon nitride sintered body has a porosity of 1% or less, a three-point bending strength of 800 to 1000 MPa, and a fracture toughness of 5.7 to 6.5 MPa·m1/2. According to this structure, even when an inexpensive silicon nitride powder manufactured by metal nitriding method is used, there can be provided a silicon nitride abrasion resistant member having a mechanical strength, high abrasion resistance, and a rolling life, equal to or higher than those of conventional silicon nitride sintered bodies, and excellent workability, and a method for manufacturing the member can be provided.
    Type: Grant
    Filed: September 27, 2004
    Date of Patent: April 21, 2009
    Assignees: Kabushiki Kaisha Toshiba, Toshiba Materials Co., Ltd.
    Inventors: Michiyasu Komatsu, Minoru Takao
  • Publication number: 20070161493
    Abstract: A silicon nitride abrasion resistant member is formed of silicon nitride sintered body containing 2% to 4% by mass of a rare earth element in terms of oxide thereof as a sintering aid, 2% to 6% by mass of an Al component in terms of oxide thereof, and 2% to 7% by mass of silicon carbide. The silicon nitride sintered body has a porosity of 1% or less, a three-point bending strength of 800 to 1000 MPa, and a fracture toughness of 5.7 to 6.5 MPa·m1/2. According to this structure, even when an inexpensive silicon nitride powder manufactured by metal nitriding method is used, there can be provided a silicon nitride abrasion resistant member having a mechanical strength, high abrasion resistance, and a rolling life, equal to or higher than those of conventional silicon nitride sintered bodies, and excellent workability, and a method for manufacturing the member can be provided.
    Type: Application
    Filed: September 27, 2004
    Publication date: July 12, 2007
    Applicants: Kabushiki Kaisha Toshiba, Toshiba Materials Co., Ltd.
    Inventors: Michiyasu Komatsu, Minoru Takao
  • Patent number: 6642165
    Abstract: Wear resistant member for electronic equipment comprises a silicon nitride sintered body that contains conductivity enhancing particles, and has electrical resistivity in the range from 1 to 105 &OHgr;·m. In silicon nitride sintered body, agglomeration of conductivity enhancing particles in which distance between conductivity enhancing particles is less than 1 &mgr;m exists by 30% or less by area ratio per unit area. Wear resistant member is used for a bearing ball or the like, being applied in a rotation actuator of electronic equipment such as a magnetic recorder and optical disk drive. Malfunction of electronic equipment due to static electricity may be cancelled due to electrical resistivity that silicon nitride sintered body has.
    Type: Grant
    Filed: August 13, 2001
    Date of Patent: November 4, 2003
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kimiya Miyashita, Michiyasu Komatsu, Hisao Yabe, Minoru Takao, Yukihiro Takenami, Yoshiyuki Fukuda, Katsuhiro Shinosawa
  • Patent number: 6485830
    Abstract: In material for ceramic ball that has a spherical portion of approximate sphere at both ends thereof and a belt-like portion at a center thereof over an entire circumferential direction, a difference between a diagonal diameter of the belt-like portion and a polar diameter of the spherical portion is 100 &mgr;m or less. A height of the belt-like portion from the spherical portion is preferable to be 1 mm or less. A width of the belt-like portion is preferable to be 5 mm or less. The material for ceramic ball can be used for material for bearing balls for instance. When applying in such a usage, the material for ceramic ball essentially consists of silicon nitride, Vickers hardness thereof being preferable to be 1400 or more. In the material for ceramic ball of the present invention, a difference between a diagonal diameter of a belt-like portion and a polar diameter of a spherical portion is set at 100 &mgr;m or less.
    Type: Grant
    Filed: September 27, 2000
    Date of Patent: November 26, 2002
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroshi Komorita, Minoru Takao, Isao Ikeda, Hiroki Tonai
  • Patent number: 6475940
    Abstract: Wear resistant member for electronic equipment comprises a zirconium oxide sintered body of which specific resistance is in the range from 1 to 105 &OHgr;·m. A conductivity enhancer of which specific resistance is 10−5 &OHgr;·m or less is compounded to a zirconium oxide sintered body to materialize specific resistance from 1 to 105 &OHgr;·m. For a conductivity enhancer, carbides and nitrides of various kinds of metals can be used. Wear resistant member can be used as a bearing ball, being applied in a rotational driver of electronic equipment such as a magnetic recording device and an optical disk device. Deficiency due to static electricity of electronic equipment is cancelled due to specific resistance that a zirconium oxide sintered body has.
    Type: Grant
    Filed: May 16, 2001
    Date of Patent: November 5, 2002
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yukihiro Takenami, Isao Ikeda, Minoru Takao, Hiroki Tonai, Yoshiyuki Fukuda, Hisao Yabe, Michiyasu Komatsu
  • Publication number: 20020098966
    Abstract: Wear resistant member for electronic equipment comprises a silicon nitride sintered body that contains conductivity enhancing particles, and has electrical resistivity in the range from 1 to 105 &OHgr;·m. In silicon nitride sintered body, agglomeration of conductivity enhancing particles in which distance between conductivity enhancing particles is less than 1 &mgr;m exists by 30% or less by area ratio per unit area. Wear resistant member is used for a bearing ball or the like, being applied in a rotation actuator of electronic equipment such as a magnetic recorder and optical disk drive. Malfunction of electronic equipment due to static electricity may be cancelled due to electrical resistivity that silicon nitride sintered body has.
    Type: Application
    Filed: August 13, 2001
    Publication date: July 25, 2002
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Kimiya Miyashita, Michiyasu Komatsu, Hisao Yabe, Minoru Takao, Yukihiro Takenami, Yoshiyuki Fukuda, Katsuhiro Shinosawa
  • Publication number: 20020013211
    Abstract: Wear resistant member for electronic equipment comprises a zirconium oxide sintered body of which specific resistance is in the range from 1 to 105 &OHgr;·m. A conductivity enhancer of which specific resistance is 10−5 &OHgr;·m or less is compounded to a zirconium oxide sintered body to materialize specific resistance from 1 to 105 &OHgr;·m. For a conductivity enhancer, carbides and nitrides of various kinds of metals can be used. Wear resistant member can be used as a bearing ball, being applied in a rotational driver of electronic equipment such as a magnetic recording device and an optical disk device. Deficiency due to static electricity of electronic equipment is cancelled due to specific resistance that a zirconium oxide sintered body has.
    Type: Application
    Filed: May 16, 2001
    Publication date: January 31, 2002
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Yukihiro Takenami, Isao Ikeda, Minoru Takao, Hiroki Tonai, Yoshiyuki Fukuda, Hisao Yabe, Michiyasu Komatsu