Patents by Inventor Michiharu Naka

Michiharu Naka 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).

  • Publication number: 20020019319
    Abstract: This invention is to provide a conductive grease which is less to decrease conductivity as a time passes. The conductive grease comprises abase oil, a thickener, a conductive solid powder, and at least one kind of a wear inhibitor, an extreme pressure agent and an oiliness agent, wherein an amount of the conductive solid powder added is 0.1 to 10 wt %, and an amount of the at least one kind of a wear inhibitor, an extreme pressure agent and an oiliness agent added is 0.1 to 10 wt %. Further, the conductive grease comprises the base oil and at least one of conductive additives, and the conductive additives are fibrous carbon, metallic particle, metallic compound particle and carbon nano-tube. The conductive grease to be packed into the rolling bearing comprises conductive fine particles such as carbon black and has an oil separation degree of 2% or lower.
    Type: Application
    Filed: June 21, 2001
    Publication date: February 14, 2002
    Applicant: NSK LTD.
    Inventors: Katsuaki Denpo, Atsushi Yokouchi, Koichi Hachiya, Michiharu Naka, Tooru Shouda, Hideki Koizumi
  • Patent number: 6340244
    Abstract: A rolling bearing for an HDD being excellent in the resistance to fretting wear, capable of lowering the torque and relieving the torque change and having a long life while exerting no undesirable effect on various bearing properties. A rolling bearing for hard disk drives wherein a cage 7 supports a plural number of rolling elements 5 located between an inner ring 2 and an outer ring 4 and sealing members 6,6 fixed to the both ends in the axial direction of one of said inner ring 2 and said outer ring 4 are opposite to each other, wherein a lubricating oil has been injected into the bearing space formed between said sealing members 6,6 at the both ends in the axial direction so as to amount to 1 to 50% by volume of the bearing space.
    Type: Grant
    Filed: June 5, 1998
    Date of Patent: January 22, 2002
    Assignee: NSK Ltd.
    Inventors: Yasunobu Fujita, Masao Yamamoto, Kouichi Hachiya, Atsushi Yokouchi, Toshikazu Yabe, Emiko Shiraishi, Michiharu Naka
  • Publication number: 20020006879
    Abstract: This invention relates to a fretting-resisting roller bearing of which the various characteristics are not adversely affected and which achieves a higher temperature and a higher speed as well as a longer life. In a roller bearing comprised of a plurality of rolling elements held between inner and outer races with a cage interposed therebetween, the oil film of lubricating oil of which the dynamic viscosity at 40° C. is 20 to 150 mm2/s is formed on the raceway surfaces of the inner and outer races, the cage and the rolling elements and grease is enclosed.
    Type: Application
    Filed: November 25, 1998
    Publication date: January 17, 2002
    Inventors: YASUNOBU FUJITA, KEISUKE KIMURA, MICHIHARU NAKA
  • Publication number: 20020002119
    Abstract: A lubricating grease composition having a basic grease composition containing a synthetic oil as a base oil, and a lithium soap as a thickener. 0.5 to 10% by weight with respect to the basic grease composition total amount of at least one additive selected from the group consisting of an organic molybdenum compound, an organic fatty acid compound or an derivative thereof, and an organic phosphorus compound is added is provided. Accordingly, the present invention can provide a lubricating grease composition capable of providing excellent lubricating characteristics, fretting wear resistance property, and impact resistance property.
    Type: Application
    Filed: March 21, 2001
    Publication date: January 3, 2002
    Inventors: Michiharu Naka, Atsushi Yokouchi, Koichi Hachiya, Toru Takamizawa, Jun Kuraishi, Yasunobu Fujita, Hiroshi Kimura, Akimi Kimura, Yuji Onuki
  • Publication number: 20010034306
    Abstract: The present invention is to provide a rolling bearing suitable for the use under a high temperature, high speed, high load and high vibration condition, having a good rust-preventive performance and the excellent flaking life without a hazard to a human body. A rolling bearing is described, comprising an inner race, an outer race and rolling elements, with a grease composition comprising, as the main components, a base oil, a thickener and at least one kind of a rust-preventive additive made from a naphthenate or a succinic acid derivative, packed in a bearing space formed by at least the inner race, the outer race and the rolling elements, said at least one kind of a rust-preventive additive is present in an amount of 0.1 to 10% by weight based on the total amount of the grease composition.
    Type: Application
    Filed: February 22, 2001
    Publication date: October 25, 2001
    Inventors: Kenichi Iso, Atsushi Yokouchi, Michiharu Naka
  • Publication number: 20010023795
    Abstract: In a lubricant application system, a prescribed volume of lubricant is transferred from a lubricant discharge port 8 of a prescribed liquid volume discharge device to a rolling element 703 of a rolling bearing 700 in a state in which the lubricant discharge port 8 is positioned directly above and sufficiently close to the rolling element 703, whereby the lubricant is applied to the interior of the rolling bearing 700. Further, the application system inspects whether or not a prescribed volume of lubricant is injected from the discharge device for injecting a lubricant into the interior of a rolling bearing 700.
    Type: Application
    Filed: May 17, 2001
    Publication date: September 27, 2001
    Inventors: Masaaki Sekine, Katsuyoshi Yamashita, Michiharu Naka
  • Patent number: 6251841
    Abstract: The present invention provides a grease composition excellent in both rust-proofing properties and safety. The grease composition comprises a lubricating base oil and a thickener, and further comprises a lipophilic organic inhibitor, a nonionic surface active agent and a hydrophilic organic inhibitor selected from the group consisting of lanolin fatty acid derivative and alkanolamine derivative modified with a hydrophilic group each in an amount of from 0.1 to 10% by weight based on the total weight of said grease composition.
    Type: Grant
    Filed: March 29, 1999
    Date of Patent: June 26, 2001
    Assignees: NSK Ltd., Kyodo Yushi Co., Ltd.
    Inventors: Hideki Koizumi, Atsushi Yokouchi, Kenichi Iso, Michiharu Naka, Toshiaki Endo, Atsushi Shibayama
  • Patent number: 5922654
    Abstract: The invention relates to lubricant compositions which contain (1) specific organometallic compounds, or (2) a specific organometallic compound and an ashless sulfur compound, or (3) an organomolybdenum compound and an ashless sulfur compound having a specific group, or (4) a specific organometallic compound and a phosphorus compound, or (5) an organonickel compound, or (6) a specific organometallic compound. The lubricant compositions of the invention not only can impart far higher load bearing properties and extreme-pressure properties than conventional ones to members to which the compositions are applied, but also show an excellent lubricating performance at high temperatures.
    Type: Grant
    Filed: June 23, 1997
    Date of Patent: July 13, 1999
    Assignee: NSK Ltd.
    Inventors: Masahiko Yamazaki, Jun Kuraishi, Kenichi Iso, Atsushi Yokouchi, Michiharu Naka
  • Patent number: 5840666
    Abstract: A grease composition comprising a base oil, a thickener selected from a metallic soap and a urea compound, and an inorganic filler having an average particle size of not greater than 2 .mu.m, and a rolling bearing having sealed therein a grease composition comprising a base oil, a urea thickener, and an inorganic filler having an average particle size of not greater than 2 .mu.m.
    Type: Grant
    Filed: December 20, 1996
    Date of Patent: November 24, 1998
    Assignee: NSK Ltd.
    Inventors: Atsushi Yokouchi, Hideki Koizumi, Kenichi Iso, Michiharu Naka
  • Patent number: 5728659
    Abstract: A grease composition for a rolling bearing comprising, based on 100 parts by weight of a base oil, 10 to 60 parts by weight of a mixture of diurea compounds as a thickener having a composition of 25 to 90 mol % of a diurea compound represented by the formula (1), 9 to 50 mol % of a diurea compound represented by the formula (2), 1 to 30 mol % of a diurea compound represented by the formula (3), wherein R.sup.1 stands for an aromatics-containing hydrocarbon group having 7 to 12 carbon atoms, R.sup.2 stands for a divalent aromatics-containing hydrocarbon group having 6 to 15 carbon atoms, and R.sup.3 stands for a cyclohexyl group or an alkylcyclohexyl group having 7 to 12 carbon atoms, a value of (number of R.sup.1 /(number of R.sup.1 +number of R.sup.3)) in the mixture being 0.55 to 0.95.
    Type: Grant
    Filed: February 20, 1997
    Date of Patent: March 17, 1998
    Assignees: NSK Ltd., Nippon Oil Co., Ltd.
    Inventors: Michiharu Naka, Atsushi Yokouchi, Hideki Koizumi, Kenichi Iso, Hirotugu Kinoshita, Souichi Nomura, Fumihiro Itano
  • Patent number: 5714444
    Abstract: A grease composition comprising a base oil and a thickener, in which the thickener comprises a lithium soap of C.sub.12 -C.sub.24 fatty acid containing no hydroxyl group and a lithium soap of C.sub.12 -C.sub.24 fatty acid containing a hydroxyl group and the base oil has kinematic viscosity of 25 to 200 mm.sup.2 /sec at 40.degree. C. and contains 10 to 70% by weight of an ester oil, the grease composition containing from 20 to 30% by weight of the two specific thickeners. Prolonged continuous operation of bearings into which the grease composition is sealed does not cause an amount of splashing grease to increase and noiseless property to be deteriorated.
    Type: Grant
    Filed: November 17, 1995
    Date of Patent: February 3, 1998
    Assignee: NSK Ltd.
    Inventors: Atsushi Yokouchi, Masao Yamamoto, Atsuhiro Yamamoto, Michiharu Naka
  • Patent number: 5707944
    Abstract: A grease composition comprising a base oil containing not less than 10% by weight of an ester oil based on the total base oil and having a kinematic viscosity of 50 to 200 mm.sup.2 /sec at 40.degree. C. and 15 to 35% by weight, based on the total grease composition, of a diurea compound represented by formula (I): ##STR1## wherein R.sub.2 represents an aromatic hydrocarbon group having 6 to 15 carbon atoms; and R.sub.1 and R.sub.3, which may be the same or different, each represent an aromatic hydrocarbon group having 6 to 12 carbon atoms or an aliphatic hydrocarbon group having 8 to 20 carbon atoms, the proportion of the aromatic hydrocarbon groups in the total of R.sub.1 and R.sub.3 being 50 to 100 mol %. When applied to outer race rotating bearings, the grease composition is excellent in flaking resistance, leak resistance, and low noise properties and prevents premature seizing under high temperature and high speed conditions.
    Type: Grant
    Filed: October 17, 1995
    Date of Patent: January 13, 1998
    Assignees: NSK Ltd., Kyodo Yushi Co., Ltd.
    Inventors: Atsushi Yokouchi, Hideki Koizumi, Kenichi Iso, Michiharu Naka, Toshiaki Endo, Yoichi Suzuki
  • Patent number: 5656582
    Abstract: The rust preventive lubricating oil of the present invention concerns a base oil and a rust-preventive agent in an amount of 2-20% by weight on the basis of the whole rust preventive lubricating oil, wherein the base oil contains an ether oil in an amount of at least 20% by weight on the basis of the whole rust preventive lubricating oil. The rust preventive lubricating oil can be applied to the surface of raceway tracks of inner and outer rings, cages for bearings, as well as to bearings, to prevent development of rust, to inhibit generation of cage sound, and to obtain good lubricity, while retaining good compatibility with a grease to be later charged.
    Type: Grant
    Filed: June 21, 1996
    Date of Patent: August 12, 1997
    Assignee: NSK Limited
    Inventors: Emiko Shiraishi, Hiroyuki Ito, Masao Yamamoto, Michiharu Naka, Akira Suzuki, Shigeki Maehara
  • Patent number: 5640769
    Abstract: To provide a ball bearing that insures reasonable endurance and which reduces the necessary torque for rotation while causing less fluctuations in torque, a synthetic resin cage of the ball bearing for retaining a plurality of balls so as to roll freely is impregnated with a lubricating oil having a viscosity of 10 to 150 mm.sup.2 /s at 40.degree. C. in an amount of 0.1 to 1.0% by weight of the cage, a film of the lubricating oil is formed in a thickness of 0.03 to 20 .mu.m on the surfaces of an inner race, an outer race, balls and the cage, and the amounts of the oiliness agent and the rust inhibitor that are to be contained in the lubricating oils are limited to the specified ranges.
    Type: Grant
    Filed: December 30, 1994
    Date of Patent: June 24, 1997
    Assignee: NSK Ltd
    Inventors: Akira Suzuki, Jiami Pu, Magozou Hamamoto, Kazuo Akagami, Michiharu Naka, Masahiro Takahashi, Mamoru Aoki, Hiroyuki Ito, Masao Yamamoto, Emiko Shiraishi
  • Patent number: 5575570
    Abstract: A cage for a rolling bearing; the cage is obtained by molding a resin composition comprising 100 parts by weight of a heat-resistant and oil-resistant resin and from 5 to 100 parts by weight of a polyolefin and immersing the resulting molded article in a lubricating oil. Also is disclosed is a rolling bearing with the cage fitted therein and having been subjected to oil plating.
    Type: Grant
    Filed: July 7, 1995
    Date of Patent: November 19, 1996
    Assignee: NSK Ltd.
    Inventors: Takahiko Uchiyama, Youichiro Sugimori, Toshimi Takajo, Michiharu Naka, Masao Yamamoto, Emiko Shiraishi, Atushi Yokouchi
  • Patent number: 5498357
    Abstract: A grease composition for high-temperature, high-speed and high-load bearings comprises (i) a lubricating base oil composed of an alkyldiphenyl ether lubricant as an essential ingredient and having a kinematic viscosity of 90-160 cSt at 40.degree. C., and (ii) 22-30 wt. %, based on the grease composition, of a diurea compound as a thickener. The diurea compound is represented by the following formula: ##STR1## wherein R.sub.2 means an aromatic hydrocarbon group having 6-15 carbon atoms, R.sub.1 and R.sub.3 denote an aromatic hydrocarbon group having 6-12 carbon atoms or a linear alkyl group having 8-20 carbon atoms, and the proportion of aromatic hydrocarbon groups in R.sub.1 and R.sub.3 is 70-95 mole %. The NLGI thickness grade of said composition is in a range of from No. 1 to No. 3.
    Type: Grant
    Filed: December 27, 1993
    Date of Patent: March 12, 1996
    Assignees: NSK Ltd., Kyodo Yushi Co., Ltd.
    Inventors: Michiharu Naka, Hideki Koizumi, Yuzo Takahashi, Koici Goto, Toshiaki Endo, Yoichi Suzuki
  • Patent number: 5462684
    Abstract: A grease composition for a high-speed rolling bearing contains an alkyl diphenyl ether oil as a base oil, and at least one of diurea compounds represented by the formula (1) ##STR1## wherein R.sup.1 denotes a divalent aromatic hydrocarbon residue having 6 to 15 carbon atoms and R.sup.2 and R.sup.3 may be the same or different and each represent a cyclohexyl group, a cyclohexyl derivative group having 7 to 12 carbon atoms or an alkyl group having 8 to 20 carbon atoms. The diurea compound is contained as a thickener in the base oil. The content in percent of the cyclohexyl group and the cyclohexyl derivative group in the diurea compound is such that a value of [{(numbers of cyclohexyl groups and derivative groups thereof)/(numbers of cyclohexyl groups and derivative groups thereof plus numbers of alkyl groups)}.times.100] is equal to 50 to 100%.
    Type: Grant
    Filed: June 23, 1993
    Date of Patent: October 31, 1995
    Assignees: Nippon Oil Co., Ltd., NSK Ltd.
    Inventors: Michiharu Naka, Hideki Koizumi, Yuzo Takahashi, Hirotugu Kinoshita, Masaru Mishima
  • Patent number: 5401105
    Abstract: To provide a ball bearing that insures reasonable endurance and which reduces the necessary torque for rotation while causing less fluctuations in torque, a synthetic resin cage of the ball bearing for retaining a plurality of balls so as to roll freely is impregnated with a lubricating oil having a viscosity of 10 to 150 mm.sup.2 /s at 40.degree. C. in an amount of 0.1 to 1.0% by weight of the cage, a film of the lubricating oil is formed in a thickness of 0.03 to 20 .mu.m on the surfaces of an inner race, an outer race, balls and the cage, and the amounts of the oiliness agent and the rust inhibitor that are to be contained in the lubricating oils are limited to the specified ranges.
    Type: Grant
    Filed: December 28, 1993
    Date of Patent: March 28, 1995
    Assignee: NSK Ltd.
    Inventors: Akira Suzuki, Jiami Pu, Magozou Hamamoto, Kazuo Akagami, Michiharu Naka, Masahiro Takahashi, Mamoru Aoki, Hiroyuki Ito, Masao Yamamoto, Emiko Shiraishi
  • Patent number: 5059336
    Abstract: A grease composition for a high speed anti-friction bearing contains, in a synthetic lubricant base oil, (A) 2 to 30 wt. % of a thickening agent consisting of an urea comopund, (B) 0.2 to 30 wt. % of sorbitan monooleate, (C) 0.2 to 3.0 wt.% of barium sulfonate, and (D) 0.2 to 3.0 wt. % of barium lanolate, as indispensable components, each weight percentage being based on the total weight of the composition.
    Type: Grant
    Filed: August 16, 1990
    Date of Patent: October 22, 1991
    Assignees: Nippon Seiko Kabushiki Kaisha, Nippon Oil Co., Ltd.
    Inventors: Michiharu Naka, Hideki Koizumi, Yukari Kondoh, Hirotugu Kinoshita, Mokoto Seikiya, Masaru Mishima
  • Patent number: 4410435
    Abstract: A lithium complex grease for rolling bearings which has high dropping points and is capable of maintaining for a long time an excellent stability of a thickener micell under a high temperature, high adhesion, heat resistance, water resistance, rust resistance, load resistance, low noises and other high-level properties and a method of producing such lithium complex grease. The lithium complex greases are characterized in that base greases containing a base oil, a fatty acid having 12 to 24 carbon atoms, a dicarboxylic acid having 4 to 12 carbon atoms and/or a dicarboxylic acid ester and a lithium hydroxide are thickened with a phosphate ester and/or a phosphite ester. A method of producing the lithium complex greases is characterized in that the base greases having the above composition are added by the phosphate ester and/or the phosphite ester, and thickened under a reaction at a temperature of more than 210.degree. C. (410.degree. F.).
    Type: Grant
    Filed: December 29, 1981
    Date of Patent: October 18, 1983
    Assignee: Nippon Seiko Kabushiki Kaisha
    Inventors: Michiharu Naka, Takayuki Yatabe, Hideki Koizumi