A rolling bearing that can easily achieve the higher lubricating characteristic including the smaller rotational torque while employing the existing bearing shape and lubricant is provided. A rolling bearing 1 includes: an inner ring 2 and an outer ring 3 as a race ring; a plurality of rolling elements 4 held between the inner and outer rings; a retainer 5 that retains the rolling elements 4; a sealing member 11 provided at openings on opposite ends in an axial direction of the inner ring 2 and the outer ring 3; and grease 12 to be enclosed in an in-bearing space. At least one member selected from the inner ring 2, the outer ring 3, the retainer 5, and the sealing member 11 is provided with a flocking part 6 formed by flocking fiber on a surface of the member which is in contact with the grease 12.

The invention relates to a lubricated rolling bearing for blade roots including a coating made of a chemical compound of lamellar structure.

Provided is a grease composition containing a base oil, a thickener, and an additive. The base oil contains a poly--olefin and has a kinematic viscosity of 20-60 mm.sup.2/s at 40 C. The thickener contains a urea compound produced by reacting a diisocyanate compound with a mixed amine containing an alicyclic amine and an aromatic amine. The additive contains a phosphorous acid ester, an ether compound, and an oxidized paraffin.

A grease composition includes alkylnaphthalene as base oil and a urea compound as thickening agent. The thickening agent is an alicyclic aliphatic diurea compound contained at a ratio of 4 mass % to 10 mass % based on the total mass of the grease composition. A pivot assembly bearing device is provided with rolling bearings filled with the above grease composition. A hard disk drive device is provided with a swing arm which is swingably supported by the pivot assembly bearing device.

A rolling device for a vehicle includes an inner raceway member including first and second inner raceways; an outer raceway member including first and second outer raceways; first rolling elements disposed rollably between the first inner raceway and the first outer raceway and second rolling elements disposed rollably between the second inner raceway and the second outer raceway; and grease disposed on raceway surfaces of the first inner raceway, the first outer raceway, the second inner raceway, and the second outer raceway and rolling surfaces of the first rolling elements and the second rolling elements. The grease includes a base oil, a thickener, and additives. The grease includes a synthetic oil as the base oil. A kinematic viscosity of the base oil at 40 C. is 20 mm.sup.2/s to 50 mm.sup.2/s. The additives include a phosphorus compound, a calcium compound, and a hydrocarbon wax.

A roller bearing includes inner and outer rings each having a raceway, an annular space between the raceways, and a plurality of rolling elements and a lubricating grease in the annular space. The raceways have a predetermined roughness value within a first predetermined range, and the lubricating grease contains graphene particles uniformly dispersed in a suspension in the lubricating grease. The graphene particles have an at least substantially circular shape, a diameter within a second predetermined range and a thickness within a third predetermined range. An amount of the lubricating grease in the annular space and the first, second and third predetermined ranges are selected such that a self-regenerating mat of graphene that at least partially coats the raceways will develop in use as a result of a relative rotation between the inner and outer rings and the rolling/sliding of the rolling elements on the raceways.

To provide an axle bearing having a low torque property and superior bearing lifetime. A hub bearing 6 is configured to rotatably support a wheel of a vehicle, and has a grease composition 10 sealed in an inner space thereof. The grease composition 10 contains a base oil and a thickener. The shear stress of the grease composition at the shear rate of 1,000-10,000 s.sup.?1 at 25? C. is 3,000 Pa or less. The viscosity of the grease composition is 1 Pas or less. The yield stress of the grease composition at 25? C. measured by a dynamic viscoelasticity analysis method using a rheometer is 1,300-3,000 Pa.

The invention provides a grease composition for hub unit bearing, having (a) as a base oil a mixture of a hydrocarbon synthetic oil and an ester type synthetic oil, with the content of the ester type synthetic oil being 20 to 50 parts by mass with respect to 100 parts by mass of the total of the hydrocarbon synthetic oil and the ester type synthetic oil, and the base oil having a kinematic viscosity at 40 C. of 20 to 80 mm.sup.2/s, and (b) as a thickener a urea compound.

A compound of the present invention is represented by the general formula (1) and has a 40 C. kinetic viscosity (v) that satisfies 4 mm.sup.2/sv30 mm.sup.2/s,
C.sub.nH.sub.2n+1(OCH.sub.2CH.sub.2).sub.pO(CH.sub.2).sub.3(CO)OC.sub.mH.sub.2m+1(1) (where O represents an oxygen atom, C represents a carbon atom, H represents a hydrogen atom, m is an integer of 1 to 18, n is an integer of 1 to 12, p is an integer of 1 to 3, and 2n+m30 is satisfied). The present invention provides (i) a lubricant excellent in energy-saving, heat resistance, and low-temperature fluidity and (ii) use of the lubricant.

Provided is a grease composition which can be used as a lubricant for roller bearings, exhibits excellent high temperature durability and rust preventive property, and can prevent premature flaking on the rolling surface due to hydrogen embrittlement. A roller bearing 1 is obtained by sealing a grease composition 7 in the periphery of a rolling element 4, this grease composition 7 is composed of a base oil excluding an ester-based synthetic oil, a thickener, and an additive, the additive contains (a) an alkanolamine and (b) 2,2,4-trimethyl-1,2-dihydroquinoline or a polymer thereof but does not contain an organic sulfonate, and (a) and (b) are contained at from 0.1 to 10 parts by weight with respect to 100 parts by weight of a total amount of the base oil and the thickener, respectively.