Tapered roller bearing

A tapered roller bearing, comprising:

• an outer ring having a tapered raceway surface on an inner periphery thereof;
• an inner ring having a tapered raceway surface on an outer periphery thereof, and comprising a large-collar surface on a large-diameter side of the tapered raceway surface;
• a plurality of tapered rollers arrayed between both of the tapered raceway surfaces so as to be freely rollable;
• and
• a cage configured to receive the tapered rollers,
• wherein each of the tapered rollers has a large end side including an end surface chamfer, a relief portion, and a large end surface located between the end surface chamfer and the relief portion, the large end surface to be held in contact with and guided by the large-collar surface of the inner ring during use of the bearing,
• wherein when R represents a set curvature radius of the large end surface of each of the tapered rollers, and RBASE represents a base curvature radius from a vertex of a cone angle of each of the tapered rollers to the large-collar surface of the inner ring, the base curvature radius RBASE is 100 mm or less, and a ratio R/RBASE of the set curvature radius R to the base curvature radius RBASE is set to 0.90 or less,
• wherein the large end surface of each of the tapered rollers is formed by an annular surface centered on a tapered roller centerline and has two arc-shaped convex cross sections in a vertical cross section of the tapered roller, the two arc-shaped convex cross sections each having an actual curvature radius RACTUAL that is smaller than the set curvature radius R in the vertical cross section of the tapered roller, and
• wherein the actual curvature radius RACTUAL is defined as a radius of an arc curve passing through three points of each of the two arc-shaped convex cross sections, which are a connection point between the large end surface and the end surface chamfer, a connection point between the large end surface and the relief portion, and a midpoint between the connection points, in the vertical cross section of the tapered roller, and a ratio RACTUAL/R of the actual curvature radius RACTUAL to the set curvature radius R is a value exceeding 0.5.