Abstract: At least on a surface of a rolling element of a rolling bearing, innumerable minute concave recesses are randomly formed. An average area of the recesses is in a range of 30 to 100 ?m2, and Rymax is in a range of 0.4 to 1.0.

Abstract: A bearing for a rocker arm includes a shaft corresponding to an inner race fixed to a rocker arm interposed between an engine valve and a cam to adjust intake and exhaust, an outer race 4 in contact with the cam, located outer to the inner race, and a plurality of needle rollers located between the outer race and the inner race. The outer race includes a nitrogen-enriched layer. The grain size number of austenite crystal grains in the nitrogen-enriched layer is in a range exceeding No. 10. The outer race outside cylindrical surface has random small concave pits.

Abstract: The surfaces (2a) of at least rolling elements (2) of a roller bearing for transmissions or differentials of automobiles are provided with innumerable minute, recess-shaped cavities at random and the surface roughness parameter Ryni of the surfaces provided with the cavities is in the range of 0.4-1.0 ?m and the Sk value is not more than ?1.6.

Abstract: At least the surfaces of the rolling elements of a rolling bearing are each randomly formed with an innumerable number of microconcave-like pits. The surface roughness parameter Ryni of the surfaces provided with the pits is in the range of 0.4-1.0 ?m, and the Sk value is ?1.6 or below.

Abstract: A needle roller bearing supporting the shaft part of a crankshaft comprises an outer ring having a plurality of outer ring members divided by parting lines extending in the axial direction of the bearing, a plurality of needle rollers arranged on the track surface of the outer ring such they can roll, and a retainer having pockets for housing the plurality of needle rollers. Thus, the roundness of the inner diameter surface of the outer ring is set within the range of 0 ?m to 20 ?m.