A high-speed shaft assembly includes a shaft of a first material and an outer member of a second material disposed about the shaft, the shaft or outer member being rotatable about an axis. The two materials have substantially different coefficients of thermal expansion such that the shaft and/or the outer member is relatively displaceable along the axis at temperatures over 120° C. and less than −18° C. A bearing inner ring is disposed about the shaft and has an outer race which is a cylindrical surface or an annular groove. A bearing outer ring is disposed about the inner ring and coupled with the outer member. The outer ring has an outer race which is the other one of the cylindrical surface and the groove. A plurality of balls disposed between the races are displaceable axially along the cylindrical race surface during relative displacement of the shaft and outer member.

It is possible to provide an iron-based sintered sliding material excellent in the sliding performance. Provided is an iron-based sintered sliding material including, a base containing, by mass, 3 to 15% of S, 0.2 to 6% in a total amount of at least one selected from the group consisting of Cr, Ca, V, Ti, and Mg, and a remainder of Fe and inevitable impurities, sulfide particles containing at least one selected from the group consisting of Cr, Ca, V, Ti, and Mg being dispersed in the base, and pores.

In a heat treatment method for obtaining a bearing ring for an annular roller bearing whose thickness changes in an axial direction, the heat treatment method includes (A) applying a quenching process to a work which is annular, made of high carbon chromium bearing steel, and having a thickness changing in an axial direction, (B) applying a tempering process to the work which is quenched to entirely soak the work in cooling liquid and inductively heat the work in a state that the work is soaked in the cooling liquid, and (C) applying a finishing process to the work which is tempered.

A rolling bearing providing a first ring and a second ring in relative rotation one each other, and at least one row of rolling elements being arranged between the said rings. At least one the rings is made by metal injection molding process including the successive steps of mixing a metal powder with a thermoplastic binder, forming a part by injection of the mixed powder in a closed die, debinding such a formed part in a furnace, sintering to densify the part, and quenching to set a ring hardness, to improve wear resistance and fatigue life.

A tapered roller bearing for an automobile includes an inner ring including a raceway surface having a tapered shape on an outer periphery, an outer ring including a raceway surface having a tapered shape on an inner periphery, a plurality of tapered rollers incorporated into a space defined between the raceway surfaces, and a retainer configured to receive the tapered rollers. The inner and outer rings are each made of carburized steel, and the raceway surfaces of the inner and outer rings each have a straight generating line shape. The tapered rollers each are made of high carbon chromium bearing steel, and each have a rolling surface including a straight portion, which is formed at a center portion in an axial direction, and crowning portions, which extend from the straight portion to both end portions. The crowning portions are each formed of logarithmic crowning.

A tapered roller bearing includes an inner ring having a tapered raceway surface and a large-collar surface on a large-diameter side of the raceway surface, and tapered rollers. Each of the rollers has a large end surface guided by the large-collar surface. When R represents a set curvature radius of the large end surface and R.sub.BASE represents a base curvature radius from a vertex of a cone angle of each of the tapered rollers to the large-collar surface, the base curvature radius R.sub.BASE is 100 mm or less, and a ratio R/R.sub.BASE of the set curvature radius R to the base curvature radius R.sub.BASE is set to 0.90 or less. When R.sub.ACTUAL represents an actual curvature radius of the large end surface of each of the tapered rollers, a ratio R.sub.ACTUAL/R of the actual curvature radius R.sub.ACTUAL to the set curvature radius R exceeds 0.5.

A connection element providing a first ring and a second ring, the two rings rotating relative to one another about a central axis, the first ring having a contact portion with a contact surface interacting with the second ring for the relative rotation, and a fastening portion configured to be rigidly secured to a support. The contact portion is made of a first material and the fastening portion is made of a second material, different to the first material, the first material having a hardness strictly greater than that of the second material, and the second material having a structural fatigue strength strictly greater than that of the first material.

A sliding bearing may include an uncoated shaft and a bearing bush. The uncoated shaft may include a shaft material. The bearing bush may include a sintered bearing bush material. The shaft may be slidingly and moveably guided, relative to the bearing bush, within the bearing bush. The bearing bush material may have a residual porosity of 8 percent or more. A volume of the residual porosity may be filled with an oil up to 80 percent or more.

A sintered bearing bush material for a sliding bearing may include: 0.5 to 1.7 percentage by weight carbon; 0.2 to 1.2 percentage by weight manganese; 0.2 to 1.2 percentage by weight sulphur; 1.2 to 2.4 percentage by weight nickel; 1.0 to 2.1 percentage by weight molybdenum; 3.0 to 7.0 percentage by weight copper; 0.2 to 1.2 percentage by weight tin; 0 to 0.8 percentage by weight phosphorus; and a residual component.

A rolling bearing, a rolling device, and a method of manufacturing the rolling device are provided, by which a long life can readily be implemented by suppressing surface damage even on the use condition that the oil film formation performance of a rolling part is poor. A rolling device includes: a first rolling component made of SUJ2; and a second rolling component made of SUJ2 and configured to contact the first rolling component. A surface of a rolling part of the first rolling component is greater in arithmetic mean roughness than a surface of a rolling part of the second rolling component. The arithmetic mean roughness of the surface of the rolling part of the second rolling component is 0.07 μm or more and 0.20 μm or less.