A rolling bearing is a tapered roller bearing, a cylindrical roller bearing, or a deep groove ball bearing including an inner ring, an outer ring, and a rolling element, each of the inner ring, the outer ring, and the rolling element being composed of a steel, the rolling bearing having a quench-hardened layer in at least one of an inner ring raceway surface of the inner ring, an outer ring raceway surface of the outer ring, and a rolling contact surface of the rolling element. A ratio of a total area of a plurality of martensite crystal grains in the quench-hardened layer is more than or equal to 70%. The plurality of martensite crystal grains are classified into a first group and a second group. An average grain size of the martensite crystal grains belonging to the first group is less than or equal to 0.97 μm.

The present invention provides a sliding member which enables further reduction of friction and improvement of seizure resistance without deteriorating wear resistance of a sliding surface. The sliding member includes a porous metal base material, and a resin material with which the porous metal base material is impregnated. The sliding member includes an exposed sliding surface. The sliding surface includes a top surface made of the resin material, and a bottom surface made of the porous metal base material. A height from the bottom surface to the top surface is 10 to 30 μm, and the resin material includes fluorine resin.

A bearing unit having an axis of rotation (X) for a wheel hub assembly for motor vehicles includes stationary radially outer ring, a rotatable wheel hub or first radially inner ring, a rotatable second radially inner ring having an axially external first axial contact edge, an axially internal second axial contact edge having a radially external first contact surface configured to abut a surface of the first radially inner ring, a radially internal second contact surface, and a relief groove interposed radially between the first contact surface and the second contact surface, two rows of rolling bodies interposed between the radially outer ring and the second radially inner ring, and a joint including a bell, the second contact surface contacting a surface of the bell and axial locks the radially inner ring, and the relief groove reducing contact between the second contact edge and the surface of the bell.

A sliding member includes an overlay layer made of a resin on a side of a sliding surface of a bearing alloy layer. When a valley void volume Vvv (μm.sup.3/μm.sup.2) in the sliding surface of the overlay layer is defined as Vv1, Vv1 is in a range of 0.015≤Vv1≤0.200.

A sliding member includes a resin overlay layer on a sliding surface side coming into sliding contact with a mating member. The resin overlay layer has a surface roughness parameter Rk satisfying 0.4≤Rk≤1.2, and a surface area ratio S=S2/S1 calculated when an area of an arbitrary measurement field of view is designated by S1 and a surface area of the measurement field of view is designated by S2 satisfies 2.5≤S≤4.5.

Bearing component providing unaffected material that has a surface, which has been subjected to a hard machining process during where the temperature of the surface did not exceed the austenitizing temperature of the unaffected material. The surface of the bearing component includes a white layer formed during the hard machining process. The white layer has a nano-crystalline microstructure that includes grains having a maximum grain size up to 500 nm. The white layer is located directly adjacent to the unaffected material of the bearing component, where no dark layer is formed during the hard machining process.

A thrust washer is provided with a ring-shaped portion that surrounds an insertion hole, the thrust washer is provided with a sliding surface and an oil groove configured to allow lubricating oil to flow in, the oil groove is provided with an opening portion configured to allow the lubricating oil to flow in from the insertion hole side in an inner peripheral end side, an outer periphery end side of the ring-shaped portion of at least one of the oil groove is provided with an oil stop wall which is configured to suppress flow of the lubricating oil toward an outer periphery side of the ring-shaped portion, and a sliding area ratio of each of the sliding surfaces to a projection plane in plan view of the ring-shaped portion is provided within a range of from 60% to 85%

The cam follower roller device comprises a body, a shaft mounted on the body, a roller mounted on the shaft and able to rotate, and a plain bearing interposed radially between the shaft and the roller. An outer surface and/or an inner surface of the plain bearing comprise a plurality of cavities. The ratio of the sum of the surfaces areas of the cavities to the total surface area of the outer surface, or of the inner surface, in which the cavities are formed is between 2% and 40%. The cavities have a depth between 0.5 μm and 5 μm.

A rolling bearing includes an outer ring, an inner ring disposed coaxially with the outer ring, the inner ring being on an inner peripheral side of the outer ring. The rolling bearing includes multiple rolling elements disposed between the outer ring and the inner ring. The rolling bearing includes a strain gauge configured to detect strain of the outer ring or the inner ring. The strain gauge includes a resistor formed of a Cr composite film.

On an inner peripheral surface of a bearing hole into which a shaft is inserted, concave oil supply surfaces arranged dispersively like separated islands and a sliding surface continuous around the oil supply surfaces to hold an outer peripheral surface of the shaft are formed: a maximum height difference between the sliding surface and the oil supply surfaces is not less than 0.01% and not more than 0.5% of an inner diameter Di of the sliding surface; a surface aperture area ratio of pores at the sliding surface is not more than 10%; a surface aperture area ratio of pores at the oil supply surfaces is more than 10% and less than 40%; and an area of each of the oil supply surfaces is not less than 0.03 mm.sup.2 and not more than 0.2×Di.sup.2 (mm.sup.2).