Patents by Inventor Yosiki Yamaguchi

Yosiki Yamaguchi 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: 6214774
    Abstract: A grease for a bearing of a fan comprises a base oil selected from a various kinds of silicone oils having a viscosity of 30 to 500 mm2/s at 40 degree-C. and a viscosity of 30,000 mm2/s or less at −30 degree-C., and a diurea compound, as a thickening agent, at the compounding ratio of 2 to 30%-wt. The urea compound has a general formula of: R1—NHCONH—R2—NHCONH—R3 wherein R2 indicates a tolylene group, a diphenylmethan group or a dimethylbiphenylene group, and R1 and R3 respectively indicate a straight chain saturated alkyl group having the number of carbon atoms of 6 to 18, and an alicyclic group, and wherein the ratio of the straight chain saturated alkyl group to the alicyclic group is within a range of 5 to 95 mol-% to 95 to 5%-mol. The grease maintains its properties suitable for use in a fan, and effectively restrict or prevent generation of hoot sound, while providing satisfactory durability and cost-effctiveness.
    Type: Grant
    Filed: September 17, 1999
    Date of Patent: April 10, 2001
    Assignee: NTN Corporation
    Inventors: Seiichi Nozaki, Takahiro Koremoto, Kazuhiro Matsumoto, Yosiki Yamaguchi
  • Patent number: 5846916
    Abstract: A bearing grease composition for ABS pumps comprises:a silicone oils having a viscosity of 100 to 1,000 cSt (at 25 degree-C.), the silicone oil serving as essential components of a base oil portion, anda diurea compound, as a thickening agent, at the compounding ratio of 2 to 30%-wt, the diurea compound having a general formula of:R.sub.1 --NHCONH--R.sub.2 --NHCONH--R.sub.3wherein R.sub.2 indicates an aromatic bivalent hydroxyl group having the number of carbon atoms of 8 to 16, and R.sub.1 and R.sub.3 respectively indicate a saturated straight chain alkyl group having the number of carbon atoms of 6 to 18, and a cyclohexyl group, and wherein the ratio of the saturated straight chain alkyl group to the cyclohexyl group is within a range of 5 to 95%-mol to 95 to 5%-mol.
    Type: Grant
    Filed: January 22, 1998
    Date of Patent: December 8, 1998
    Assignee: NTN Corporation
    Inventors: Seigo Akabe, Kazuhiro Matsumoto, Yosiki Yamaguchi