Patents by Inventor Shigetaka Wada

Shigetaka Wada 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: 5523268
    Abstract: A silicon nitride sintered body includes silicon nitride as a principal component, silicon carbide dispersed therein and at least one of boron and boron compounds in an amount of from 0.005 to 0.5% by weight in terms of the weight of boron with respect to the total weight of the sintered body. The addition of boron or boron compounds improves the high-temperature characteristics such as creep resistance of the sintered body.
    Type: Grant
    Filed: December 22, 1994
    Date of Patent: June 4, 1996
    Assignee: Kabushiki Kaisha Toyota Chuo Kenkyusho
    Inventors: Yoshio Ukyo, Toshio Kandori, Shigetaka Wada
  • Patent number: 5120682
    Abstract: A sintered body of silicon nitride composed of .alpha.'-Si.sub.3 N.sub.4 and .beta.'-Si.sub.3 N.sub.4, the former being represented by the formula Y.sub.x (Si,Al).sub.12 (O,N).sub.16 (where the value of x, which denotes the amount of occluded Y, is in the range of 0<x<0.3), with the value of x for .alpha.'-Si.sub.3 N.sub.4 in the outer part of the sintered body being greater than for .alpha.'-Si.sub.3 N.sub.4 in the inner part of the sintered body. The sintered body will find use as high-temperature structural material owing to its high strength and high toughness.
    Type: Grant
    Filed: December 21, 1990
    Date of Patent: June 9, 1992
    Assignee: Kabushiki Kaisha Toyota Chuo Kenkyusho
    Inventors: Yoshio Ukyo, Shigetaka Wada
  • Patent number: 5108965
    Abstract: A composition of raw materials comprising silicon carbide, a substance containing at least one of Group IVa to VIa elements except any boride thereof, and a substance containing boron except any of the borides of Group IVa to VIa elements, and further containing, if required, carbon, or an organic compound which produces carbon as a result of thermal decomposition, or both, is fired to manufacture a silicon carbide-based material in which a boride of at least one of the elements of Groups IVa to VIa of the periodic table is dispersed. The silicon carbide-based material can be manufactured without using any of the borides of Group IVa to VIa elements as a starting material.
    Type: Grant
    Filed: August 19, 1991
    Date of Patent: April 28, 1992
    Assignee: Kabushiki Kaisha Toyota Chuo Kenkyusho
    Inventors: Toshihiko Tani, Shigetaka Wada
  • Patent number: 5104747
    Abstract: A joined assembly of a ceramic member and a metallic member having a hollow cylindrical portion which is open at one end thereof, and closed at the other end, or bottom thereof. The ceramic member has a portion fitted in the cylindrical portion in such a way that any stress acting axially upon the surface of the ceramic member may be reduced at least in the vicinity of the open end of the cylindrical portion. The two members are joined together by shrinkage fitting with at least one brazing material filling the clearance between the two members, or by chemical bonding.
    Type: Grant
    Filed: October 4, 1990
    Date of Patent: April 14, 1992
    Assignee: Kabushiki Kaisha Toyota Chuo Kenkyusho
    Inventors: Hiroaki Makino, Nobuo Kamiya, Shigetaka Wada
  • Patent number: 5081079
    Abstract: A sintered body composed of .alpha.'-silicon nitride and .beta.'-silicon nitride, and having a surface portion which contains a greater proportion of .alpha.'-silicon nitride than its inner portion does. It has high strength and excellent wear resistance. It is produced by preparing a molded body from a sintering material, disposing about the molded body a sintering material which can form a sintered product containing a greater proportion of .alpha.'-silicon nitride than the sintered product of the molded body will, and sintering the molded body and the material disposed about it.
    Type: Grant
    Filed: August 17, 1990
    Date of Patent: January 14, 1992
    Assignee: Kabushiki Kaisha Toyota Chuo Kenkyusho
    Inventors: Yoshio Ukyo, Shigetaka Wada
  • Patent number: 5081077
    Abstract: A process for producing a metal boride sintered body having a density of at least 90% of the theoretical density and a raw material composition therefor. The raw material composition is composed of a metal oxide, a metal carbide, and boron carbide, the amount of boron carbide being 5 to 20% more than the amount stoichiometrically required to form a metal boride by reaction of boron in the boron carbide with the metal element(s) in the metal oxide and metal carbide. By using this composition, it is possible to produce a metal boride sintered body having high density and high hardness without adding a sintering auxiliary or carbon and using a very high pressure.
    Type: Grant
    Filed: April 8, 1991
    Date of Patent: January 14, 1992
    Assignee: Kabushiki Kaisha Toyota Chuo Kenkyusho
    Inventors: Toshihiko Tani, Shigetaka Wada
  • Patent number: 5034355
    Abstract: A composite material comprises silicon carbide and a boride of at least one element of Groups IVa to VIa of the Periodic Table, at least a portion of the boride being in the form of fiber having an aspect ratio of 3 or above. The composite material has high toughness owing to the fibrous boride.The composite material is produced by molding a raw material mixture composed of silicon carbide, a substance containing at least one element of Groups IVa to VIa of the Periodic Table, at least a portion thereof being in the form of fiber having an aspect ratio of 3 or above, and a substance containing boron, and sintering the molded body.
    Type: Grant
    Filed: October 25, 1988
    Date of Patent: July 23, 1991
    Assignee: Kabushiki Kaisha Toyota Chuo Kenkyusho
    Inventors: Toshihiko Tani, Shigetaka Wada
  • Patent number: 4978645
    Abstract: A silicon nitride sintered body composed of .alpha.'-silicon nitride and .beta.'-silicon nitride, which are present in the ratio of 0.05-0.50 to 0.50-0.95 in terms of the peak strength ratio of X-ray diffraction, and have very small crystal grain size and specific compositions. The sintered body has high strength and high toughness and is superior in oxidation resistance.
    Type: Grant
    Filed: April 7, 1989
    Date of Patent: December 18, 1990
    Assignee: Kabushiki Kaisha Toyota Chuo Kenkyusho
    Inventors: Yoshio Ukyo, Shigetaka Wada, Kazumasa Takatori
  • Patent number: 4925815
    Abstract: A high-toughness silicon carbide composite ceramic comprising silicon carbide, 5 to 50 vol % of graphite whiskers, and sintering aid, and a method for producing the composite ceramic. The composite ceramic has high-temperature strength and fracture toughness value, and also has electrical conductivity.
    Type: Grant
    Filed: February 15, 1989
    Date of Patent: May 15, 1990
    Assignee: Kabushiki Kaisha Toyota Chuo Kenkyusho
    Inventors: Toshihiko Tani, Shigetaka Wada
  • Patent number: 4692099
    Abstract: A rotary component of a rotary device for heat engines, such as a turbine wheel of a gas turbine or a turbocharger, formed in an integral ceramic-fiber-reinforced sintered ceramic structure. The reinforcing ceramic fibers in the edges of the vanes of the rotary component are oriented radially to prevent the chipping of the edges of the vanes liable to occur in a direction perpendicular to the direction of thickness of the vanes. The rotary component is formed by molding a mixture of a ceramic powder, ceramic fibers and organic additive or additives in a mold having a cavity having the same shape as that of the rotary component except that the depth of sections of the cavity corresponding to the vanes is greater than the height of the vanes to be formed, sintering the molding, and cutting the vanes of the molding in a predetermined height.
    Type: Grant
    Filed: June 17, 1986
    Date of Patent: September 8, 1987
    Assignee: Kabushiki Kaisha Toyota Chuo Kenkyusho
    Inventors: Takahiko Homma, Shigetaka Wada
  • Patent number: 4489232
    Abstract: An apparatus for heating the fuel mixture of an internal combustion engine includes a cylindrical heating body, adapted to form a passageway between a fuel supply and an internal combustion engine, having a double walled structure formed by spaced inner and outer metallic cylinders. A plurality of plate-like ceramic heating elements having a positive temperature coefficient (PTC) of electrical resistance are inserted between the inner and outer cylinders and are urged into contact with the inner cylinder by a resilient spring member. The cylindrical heating body is sealed by welding, brazing, caulking or packing to form a gas-tight chamber enclosing the ceramic heating elements and isolating them from degradation by the fuel mixture. The cylindrical body is provided with an air hole communicating the chamber with an ambient air vent passage formed in an insulator member attached to the body thereby connecting the interior of the chamber and the ceramic heating elements therein to an external air supply.
    Type: Grant
    Filed: October 9, 1981
    Date of Patent: December 18, 1984
    Assignee: NGK Insulators, Ltd.
    Inventors: Shigetaka Wada, Toshio Yamada
  • Patent number: 4327697
    Abstract: A heater for an air-fuel mixture having a heating element of a positive temperature coefficient resistor comprises a pair of metallic thin cylinders of different sizes each having outward flange portions at least at one end combined with each other as a double cylinder; a plurality of positive temperature coefficient resistors arranged between said inner and outer cylinders with springs for pressing the positive temperature coefficient resistors to the inner cylinder wall; an electric insulator plate inserted between the outward flange portions of said inner cylinder and the outward flange portions of said outer cylinder; a fixing means anchoring between said outward flange portion of the outer cylinder and said outward flange portion of the inner cylinder for fixing integrally with electric insulator plate; an electrically insulating material inserted between an inner end portion of the inner cylinder and an inner end portion of the outer cylinder for spacing between said inner end portion of the inner cylin
    Type: Grant
    Filed: April 29, 1980
    Date of Patent: May 4, 1982
    Assignee: NGK Insulators, Ltd.
    Inventors: Shigetaka Wada, Toshio Yamada
  • Patent number: 4293514
    Abstract: A honeycomb structural body consisting of barium titanate series ceramics having a positive temperature coefficient of electric resistance can be obtained by forming a green mass consisting of a mixture of raw material powders containing at least 50% by weight of powders having perovskite type crystal structure and having a specifically limited particle size distribution, water and at least two kinds of organic binders, and drying and firing the formed article. The honeycomb structural body is suitable to be used as a heating element.
    Type: Grant
    Filed: March 2, 1979
    Date of Patent: October 6, 1981
    Assignee: NGK Insulators, Ltd.
    Inventor: Shigetaka Wada
  • Patent number: 4240890
    Abstract: An oxygen partial pressure measuring device for determining oxygen partial pressures in exhaust gases emitted from internal combustion engines comprises a metallic vessel mounted within an exhaust pipe of the engine and having an exhaust gas inlet facing to the exhaust gas flow and an exhaust gas outlet formed in a side surface of the vessel, an oxygen concentration cell shutting the exhaust gas out of the air in an air-tight manner, and a monolithic structure, what is called a honeycomb structure, located between the exhaust gas inlet and the oxygen concentration cell within the vessel for burning the exhaust gas.
    Type: Grant
    Filed: February 12, 1979
    Date of Patent: December 23, 1980
    Assignee: NGK Insulators, Ltd.
    Inventors: Tetsuo Watanabe, Shigetaka Wada, Shigeo Soejima
  • Patent number: 4222783
    Abstract: Barium titanate series semiconductive ceramics having a positive temperature coefficient of electric resistance are disclosed. The ceramics consist mainly of a barium titanate series compound and contain specifically limited small amounts of titanium dioxide, silicon oxide, aluminum oxide, at least one element selected from the group consisting of rare earth elements, yttrium, bismuth, antimony, niobium, tantalum and tungsten, at least one element selected from the group consisting of manganese, copper, iron and chromium, and zinc oxide. The ceramics are low in the variance of electric resistance values and have a low water absorption and hence are low in the change of electric properties due to the lapse of time.
    Type: Grant
    Filed: January 26, 1979
    Date of Patent: September 16, 1980
    Assignee: NGK Insulators, Ltd.
    Inventors: Senji Atsumi, Shigetaka Wada
  • Patent number: 4170530
    Abstract: An oxygen concentration cell capable of operating at a lower temperature and having a higher response speed is disclosed. The cell consists of an oxygen ion conductive solid electrolyte provided on both of its surfaces with electrodes consisting of a porous electrically conductive layer, which is formed of a platinum group metal and contains in its pores a metal oxide formed by the thermal decomposition of an oxide-forming metal compound.
    Type: Grant
    Filed: February 6, 1978
    Date of Patent: October 9, 1979
    Assignee: NGK Insulators, Ltd.
    Inventors: Tetsuo Watanabe, Shigetaka Wada
  • Patent number: 4170531
    Abstract: A simple method of producing an oxygen concentration cell provided with durable electrodes having a high activity and a low internal resistance is disclosed. The method comprises applying a solution of a compound of platinum group metal to an oxygen ion conductive solid electrolyte, converting the compound into an insoluble or hardly soluble compound by a chemical reaction, and thermally decomposing the insoluble or hardly soluble compound into the platinum group metal to be used as the electrodes of the cell.
    Type: Grant
    Filed: January 26, 1978
    Date of Patent: October 9, 1979
    Assignee: NGK Insulators, Ltd.
    Inventors: Tetsuo Watanabe, Shigetaka Wada, Shunzo Mase
  • Patent number: 4055438
    Abstract: A ceramic is disclosed which maintains a high electric resistance over a wide temperature range and has a large temperature coefficient of resistance variation at temperatures just below the aforesaid range, the PTC ceramic consisting essentially of100 parts by weight of four ingredients includingA. 1 mol of barium titanate composition,B. 0.003 to 0.05 mol of titania,C. 0.003 to 0.05 mol of alumina, andD. 0.005 to 0.06 mol of silica;0.05 to 0.3 part by weight ofE. tantalum pentoxide and/or antimony pentoxide; and0.005 to 0.03 part by weight ofF. manganese and/or copper.
    Type: Grant
    Filed: July 11, 1975
    Date of Patent: October 25, 1977
    Assignee: NGK Insulators, Ltd.
    Inventors: Shigetaka Wada, Senji Atsumi
  • Patent number: 4032752
    Abstract: Heating elements comprising a ceramic article of a honeycomb structure having a positive temperature coefficient of electric resistance and composed of barium titanate are provided with channels, in which a pair of ohmic electrodes consisting mainly of silver as a metallic component and having a surface resistivity of the electrode per se of not more than 10 m.OMEGA./cm.sup.2 are provided on both end surfaces thereof and the ohmic electrodes are coated with an electrical insulating and thermostable material.
    Type: Grant
    Filed: August 23, 1976
    Date of Patent: June 28, 1977
    Assignee: NGK Insulators, Ltd.
    Inventors: Akira Ohmura, Shigetaka Wada