Patents by Inventor Keizo Nagasawa

Keizo Nagasawa 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: 7094155
    Abstract: A spherical inner surface of the outer race and track grooves in the outer race are each defined by a post-hardening cut surface. A spherical outer surface of the inner race and track grooves in the inner race are also each defined by a post-hardening cut surface. A retainer has a spherical outer surface, a spherical inner surface and inner surfaces of the pockets, all of which are defined by a post-hardening cut surface. Respective surfaces of the retainer, the outer race and the inner race which contact with each other are formed with a surface treatment layer for reducing a frictional resistance.
    Type: Grant
    Filed: November 29, 2001
    Date of Patent: August 22, 2006
    Assignee: NTN Corporation
    Inventors: Takashi Hosoya, Keizo Nagasawa, Katsuyuki Ikei
  • Publication number: 20020077186
    Abstract: A spherical inner surface 5 of the outer race 1 and track grooves in the outer race 1 are each defined by a post-hardening cut surface. A spherical outer surface 6 of the inner race 2 and track grooves in the inner race 2 are also each defined by a post-hardening cut surface. A retainer 4 has a spherical outer surface 10, a spherical inner surface 11 and inner surfaces of the pockets 9, all of which are defined by a post-hardening cut surface. Respective surfaces of the retainer 4, the outer race 1 and the inner race 2 which contact with each other are formed with a surface treatment layer for reducing a frictional resistance.
    Type: Application
    Filed: November 29, 2001
    Publication date: June 20, 2002
    Applicant: NTN CORPORATION
    Inventors: Takashi Hosoya, Keizo Nagasawa, Katsuyuki Ikei
  • Patent number: 6258760
    Abstract: The present invention relates to a grease composition for a constant velocity joint, which has a low coefficient of friction to decrease the vibrations of CVJ, which comprises a base oil, a urea thickening agent, (A) a molybdenum dialkyldithiocarbamate, (B) at least one molybdenum di(alkyl or aryl)dithiophosphate represented by formula (I): wherein R1 represents a primary or secondary alkyl group or an aryl group, and (C) at least one sulfur-containing additive selected from the group consisting of an ashless dithiocarbamate, a polysulfide, zinc dithiocarbamate, sulfurized fat and oil, an olefin sulfide, a sulfur-phosphorus extreme pressure additive, and a thiadiazole extreme pressure additive, wherein each of the components (A), (B) and (C) is in an amount of 10% by weight or less based on the total weight of the grease composition.
    Type: Grant
    Filed: April 21, 2000
    Date of Patent: July 10, 2001
    Assignees: Showa Shell Sekiyu K.K., NTN Corporation
    Inventors: Takahiro Ozaki, Tsutomu Yoshida, Takao Nishimura, Ryuichi Masumori, Keizo Nagasawa, Yukio Asahara
  • Patent number: 5952273
    Abstract: A grease composition for constant velocity joints comprising: (a) a base oil; (b) a diurea thickener of the formula (1):R.sup.1 NH--CO--NH--C.sub.6 H.sub.4 -p-CH.sub.2 --C.sub.6 H.sub.4 -p-NH--CO--NHR.sup.2wherein R.sup.1 and R.sup.2 may be the same or different and represent aryl groups having 6 or 7 carbon atoms or cyclohexyl groups; (c) a molybdenum dialkyldithiocarbamate; (d) molybdenum disulfide; (e) at least one extreme pressure agent selected from the group consisting of zinc dithiophosphates, and sulfur-nitrogen extreme pressure agents; and (f) a phosphorus-free sulfur extreme pressure agent. The grease composition has low coefficient of friction, good performance for reducing induced thrust and high durability.
    Type: Grant
    Filed: March 25, 1998
    Date of Patent: September 14, 1999
    Assignees: Kyodo Yushi Co., Ltd,, NTN Corporation
    Inventors: Yoichi Suzuki, Takashi Okaniwa, Yukio Asahara, Keizo Nagasawa, Mitsuhiro Kakizaki, Kiyoshi Takeuchi, Yukio Hasegawa, Shinichi Takabe
  • Patent number: 5160645
    Abstract: A grease composition for constant velocity joint, particularly Zeppa type joint comprises a base oil and contains (A) a particular diurea compound as a thickener, (B) molybdenum sulfide dialkyldithiocarbamate, (C) an extreme pressure additive of zinc dithiophosphate, (D) a sulfur-phosphorus series extreme pressure additive containing no metallic element and having a sulfur content of 10-30% by weight and a phosphorus content of 0.5-5% by weight, and (E) lead dialkyldithiocarbamate as an essential component.
    Type: Grant
    Filed: February 18, 1992
    Date of Patent: November 3, 1992
    Assignee: NTN Corporation
    Inventors: Takashi Okaniwa, Kiyoshi Takeuchi, Toshiharu Kato, Keizo Nagasawa
  • Patent number: 4840740
    Abstract: Improved greases for use in homokinetic joints are proposed which comprise a base oil, a thickening agent, and an organic molybdenum compound. Greases comprising a base oil, a thickening agent, an organic molybdenum compound, and an organic zinc compound are also proposed. These greases exhibit smaller friction coefficients than conventional greases used for this purpose. On the homokinetic joint lubricated with the grease according to the present invention, the axial force produced is reduced and vibrations generated on the engine are absorbed. The vehicle is prevented from vibrating. The use of an expensive organic metallic extreme-pressure additive is unnecessary.
    Type: Grant
    Filed: August 17, 1988
    Date of Patent: June 20, 1989
    Assignee: NTN Toyo Bearing Co., Ltd.
    Inventors: Tasuku Sato, Kiyoshi Nakanishi, Yoshikazu Fukumura, Keizo Nagasawa