The present invention provides a grease composition which makes it possible to prevent deterioration in sealing properties even when base oil having a kinetic viscosity of as low as, for example, 5-40 mm2/s is used and which makes it possible to realize both sealing properties and a decrease in torque. The present invention also provides a rolling device. A sealing member (12a) comprises a plurality of sealing lips (114), (115), (116) each of which is made of an elastic material. A grease composition is sealed in void parts (121), (122) that are each located between a sliding surface of a slinger (106), on which the plurality of sealing lips slide, and two adjacent sealing lips. This grease composition contains base oil and a polar polymer. The polar polymer has a weight-average molecular weight of 5,000-140,000.

Provided is a grease composition for a wheel bearing, containing (a) a base oil consisting of a mineral oil and a synthetic hydrocarbon oil, wherein the ratio of the synthetic hydrocarbon oil to the total amount of the mineral oil and the synthetic hydrocarbon oil is 40 to 60 mass %, and the base oil has a kinematic viscosity at 40 C. of 40 to 65 mm.sup.2/s; (b) a thickener of formula (A) wherein R.sup.2 is diphenylmethane, and R.sup.1 and R.sup.3, which may be the same or different from each other, each represent cyclohexyl group or a straight-chain or branched alkyl group having 16 to 20 carbon atoms, with a molar ratio of the cyclohexyl group to the total number of moles of the cyclohexyl group and the alkyl group being 50 to 90 mol %; (c) an amine type antioxidant; and (d) an amine phosphate type antiwear agent. ##STR00001##

A ball bearing is provided which includes inner and outer races each having a raceway groove; balls; and a retainer made of a synthetic resin, and in which abnormal noise is reduced. Either the raceway groove of the inner race, or each of the raceway grooves of the inner race and the outer race has a radius of curvature which is 104% or more and 109% or less of the radius of each of the balls.

To provide a rolling bearing excellent in long-term durability. A rolling bearing includes: an inner ring and an outer ring disposed coaxially with each other; a rolling element disposed between the inner ring and the outer ring; a seal member mounted on the outer ring and configured to cover a space between the inner ring and the outer ring from an outside in an axial direction; and grease disposed between the rolling element and the seal member. The grease is in contact with an inner circumferential surface of the outer ring and the seal member. Unworked penetration of the grease is more than 178 and less than 287.

The invention provides a grease composition for rolling bearings that can exhibit improved bearing life that can secure the low noise performance under high temperature conditions, and a rolling bearing where the above-mentioned grease composition is enclosed. The grease composition for rolling bearings includes a base oil, a urea thickener and a metal deactivator. The base oil has an aniline point of 110 C. or more. The urea thickener is at least one kind of diurea compound selected from the group consisting of diurea compounds represented by formula (1): R.sup.1NHCONHR.sup.2NHCONHR.sup.3 (wherein R.sup.1 and R.sup.3, which may be the same or different from each other represent a C.sub.6-30alkyl group, a C.sub.5-8cycloalkyl group or a C.sub.6-10aryl group, and R.sup.2 represents a bivalent aromatic hydrocarbon group having 6 to 15 carbon atoms.)

A grease composition contains a base oil, a thickener, and a conductive additive (A), the base oil is a trimellitic acid ester, the conductive additive (A) is a mixture containing sepiolite and bentonite and is an organically modified additive, and an amount of the conductive additive (A) with respect to a total amount of the base oil, the thickener, and the conductive additive (A) is 3 to 10 mass %.

Object

A grease composition having a low dust generation, long life, and low low-temperature torque under an ultra high-speed, high-temperature environment with a rotational speed exceeding 30000 rpm is provided, and by applying the grease composition to a rolling bearing, the rolling bearing having a low dust generation, long life and low low-temperature torque, and a motor including such a rolling bearing are also provided.

Resolution Means

Provided are: a grease composition containing a base oil and a thickener, the base oil including a fluorine oil, an ester oil, and a polyalphaolefin oil, and the thickener including a fluorine-based thickener, a urea-based thickener, and a barium complex soap thickener, each of these components being included in the grease composition at a predetermined proportion; a rolling bearing filled with the grease composition; and a motor including the rolling bearing.

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.

Wheel hub assembly for motor vehicles, the group having a radially outer ring with at least one raceway, at least one radially inner ring with a related raceway and at least one ring of rolling bodies interposed between the radially outer ring and the radially inner ring, for sliding inside the raceways, at least one raceway being provided with superficial micropores having a depth (H) between 0.05 m and 1.5 m and defining respective micro-tanks for containing a lubricating grease.

One aspect of the disclosure relates to a sliding member. The sliding member includes: a first sliding portion having a first lubricant placed between first parts of a first friction sliding mechanism; and a second sliding portion having a second lubricant placed between second parts of a second friction sliding mechanism. The first sliding portion has a lubricant feed port from which the first lubricant is fed, and the second sliding portion has no lubricant feed port from which the second lubricant is fed. The first lubricant contains base oil and an additive. The second lubricant contains base oil and an additive containing conductive carbon. The second lubricant contains a relatively larger amount of conductive carbon than the first lubricant.