Nippon Grease Co., Ltd.

Jtekt Corporation

Ntn Corporation

Other

Minebea Company, Limited

Hiroki Iwamatsu

Seiji Okamura

Masashi Mitsuoka

Hiroshi Komiya

Koji Yoshizaki

Motoharu Akiyama

Hidenobu Mikami

Toshihiro Kawaguchi

Masahiro Okumiya

Takahiro Koremoto

Kensuke Suzuki

Masayuki Kitamura

Yasuhiro Miyamoto

Michiru Ueda

Komatsugu Nishimura

Kunihiro Yamaguchi

Toshikazu Kouno

Takao Yoshimatsu

Masami Minami

Kenji Yuki

Takehito Inada

A grease composition which is excellent in seizure resistance can be provided without deteriorating resistance to stirring in the rolling device, and a rolling device in which the grease composition intervenes to a predetermined portion can be also provided by use of a grease composition comprising a base oil and a thickener, the thickener being a diurea compound obtained by allowing an amine mixture comprising alkylphenylamine, an alkyl group of which has 8 to 16 carbon atoms, and cyclohexylamine, to react with a diisocyanate compound, the amount of cyclohexylamine in the amine mixture being 80% by mole or more and less than 91% by mole, and a worked penetration being 300 to 330.

Grease composition and rolling device

The present invention provides a grease composition which has excellent conductivity and can rapidly remove static electricity generated by using a bearing. The grease composition comprises a base oil, a thickener and a tungsten disulfide powder, wherein the average particle diameter of the tungsten disulfide powder is 0.5 to 5.0 &#x3bc;m and the amount of tungsten disulfide powder based on 100 parts by mass of the total amount of base oil and thickener is 2.0 to 4.0 parts by mass.

Grease composition and bearing

There is provided a rolling bearing which inhibits spalling of a rolling element and has a long service life even under rigorous environments. The rolling bearing comprises grease for lubricating rolling contact parts and/or sliding contact parts between a first raceway surface and a rolling elements and/or between a second raceway surface and a rolling elements, wherein the grease comprises a base oil, a thickener and an extreme pressure additive, the thickener is a diurea compound obtained by allowing an amine mixture comprising alkylphenylamine, alkyl group of which has 8 to 16 carbon atoms, and cyclohexylamine, to react with a diisocyanate compound, an amount of cyclohexylamine in the total amount of the alkylphenylamine and cyclohexylamine is from 91 to 99% by mole, and a reaction temperature of the extreme pressure additive with iron is 260&#xb0; C. or lower.

Rolling bearing

There is provided a grease composition, in which a grease film on the surface of the applied part is made thicker compared with conventional grease compositions, this thickness is maintained for a long period of time, and as a result, a longer service life against seizure compared with conventional grease compositions is assured. The grease composition comprises a base oil and a thickener, wherein the thickener is a diurea compound obtained by allowing an amine mixture comprising alkylphenylamine, an alkyl group of which has 8 to 16 carbon atoms, and cyclohexylamine, to react with a diisocyanate compound, and an amount of cyclohexylamine in the total amount of the alkylphenylamine and cyclohexylamine is from 91 to 99% by mole.

Grease composition

A rolling bearing, for use in household appliances, having a high degree of quietness, an excellent durability at high temperatures and rotational speeds, a low torque, and excellent fretting property; and a lubricant composition which can be sealed into the rolling bearing. The lubricant composition includes a base oil and a thickening agent. The base oil is a mixed oil having the following characteristics of (a) to (c): (a) The base oil consists essentially of a synthetic hydrocarbon oil and an ester oil; (b) A kinematic viscosity of the mixed oil at 40&#xb0; C. is 40 to 70 mm/second; (c) A mixing weight ratio between the ester oil of the mixed oil and the synthetic hydrocarbon oil thereof is 30:70 to 70:30. The thickening agent comprises a diurea compound shown by a formula (1): where Rand Rare a straight-chain alkyl groups having 9 to 22 carbon atoms respectively, and Ris an aromatic hydrocarbon group having 6 to 15 carbon atoms. The lubricant composition is sealed into the rolling bearing.

Lubricant composition and sealed bearing thereof

A grease composition for a pivot assembly bearing is provided and includes a thickener of 5 to 25% by mass and a base oil of 95 to 75% by mass with respect to the total mass of the thickener and the base oil. Two or more ureas selected from: urea A: a urea comprising diurea compounds having an aliphatic (ALA)/alicyclic (ACA) substituent; urea B: a urea comprising diurea compounds having an alicyclic (ACA)/aromatic (ARA) substituent; and urea C: a urea comprising diurea compounds having an aromatic (ARA)/aliphatic (ALA) substituent are used as the thickener. A poly &#x3b1;-olefin mixture having a kinematic viscosity at 40&#xb0; C. of 40 to 70 mm/s prepared by mixing poly &#x3b1;-olefin (PAO HV) having a kinematic viscosity at 40&#xb0; C. of 350 to 450 mm/s with poly &#x3b1;-olefin (PAO LV) having a kinematic viscosity at 40&#xb0; C. of 25 to 40 mm/s in a mass ratio of 15:85 to 30:70 is used as a base oil. A lead free additive may be used as an additive.

Grease composition for pivot assembly bearing and bearing for pivot assembly

Bismuth dithiocarbamate (BiDTC) is added to a urea grease containing a lubricating base oil having a poly-&#x3b1;-olefin synthetic oil or a diphenyl ether synthetic oil and a diurea thickening agent, or a fluorine grease containing a lubricating base oil having fluorinated synthetic oil and a polytetrafluoroethylene thickening agent. By taking such constitution as described above, a surface film is formed on a surface of a raceway of any one of inner and outer rings or a surface of a rolling element of a bearing. Therefore, the rolling bearing in which a grease composition having the constitution is packed can maintain an excellent lubricity for a long period of time even under severe conditions such as a high rotation, a high temperature and a heavy load. Further, the grease composition for the rolling bearing is low in harmfulness to a human body and gives little load to the environment.

Grease composition for rolling bearing and rolling bearing using the same

The present invention is directed to a grease for a rolling bearing containing poly-&agr;-olefin synthetic oil or diphenyl ether synthetic oil, a diurea thickening agent, and an organic antimony compound or an organic molybdenum compound. The present invention is also directed to a rolling bearing in which the grease for a rolling bearing is sealed. The organic antimony compound or the organic molybdenum compound reacts with a metal composing inner and outer bearing rings and a rolling element to form a compound film contributing to the reduction of the force in the tangential direction on a raceway surface of the bearing rings and a surface of the rolling element, thereby preventing an excessively large force in the tangential direction under high-speed rotation. This enables to lengthen the life of the rolling bearing used under particularly severe conditions such as high temperature, high-speed rotation and high road.

Grease for rolling bearing and grease-sealed rolling bearing

A grease to be sealed in bearings which shows good lubricating properties within a wide temperature range from low to high temperatures, whereby it can prevent bearing noise while it is cold, and maintain its good properties including excellent high-temperature durability for a long period of time. The grease contains a base oil made up of a synthetic hydrocarbon oil and an ester synthetic oil having eight or more ester groups arranged in a comb-like fashion on one side of an oil chain molecule made up of eight of more carbon atoms, as expressed by Formula below, the ratio of contents in weight of the synthetic hydrocarbon oil and the ester synthetic oil being 0.65-0.75:0.35-0.25, and 5-20 wt % of a urea thickening agent. The grease may further contain 0.1-10 wt % dithiophosphate as an extreme pressure agent. The grease may be used as grease to be sealed in a ball bearing for supporting a pulley engaging belts for transmitting automotive engine torque to prevent noise immediately after the engine is started. ##STR1## (where R.sub.1 -R.sub.4 are alkyl groups, and x and y are integers greater than 1).

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Kobe, Japan

Hiroki Iwamatsu