A holder of a tapered roller bearing is made of a resin, has a first gap between an axially inner end surface of a small-diameter-side annular part and small-diameter-side end surfaces of tapered rollers, has a second gap between an axially inner end surface of a large-diameter-side annular part and large-diameter-side end surfaces of the tapered rollers, and is provided to be capable of moving within a prescribed range along the axial direction. The surface of the axially inner end surface of the large-diameter-side annular part is rough, the large-diameter-side annular part is provided with one or more grooves which are oil-holding parts that hold the lubricating oil, and ends of the grooves are positioned to be capable of coming into contact with the tapered rollers.

A roller bearing includes a first race, a second race, and a cage disposed between the first and second races. The cage has an inner rim and a plurality of webs extending radially outboard from the inner rim and being circumferentially arranged around the inner rim to be spaced apart to define pockets. The webs have flanges that extend axially. Portions of the inner rim form inner guide surfaces of the pockets. The cage further includes a wavy outer rim circumscribing the inner rim. The outer rim has radially outer portions attached to the flanges and radially inner portions forming outer guide surfaces of the pockets. The outer rim and the flanges cooperate to define cutouts interleaved with the webs. Cylindrical roller elements are disposed in the pockets between the first and second races and have first ends adjacent the inner guide surfaces and second ends adjacent the outer guide surfaces.

A thrust roller bearing includes a plurality of rollers and a cage. Each cage pocket includes a first side surface, and a second side surface. The roller and the cage are configured to satisfy the following expression (1).
(Y1+Y2)/X<tan(3/180)(1)
Y1 represents a clearance, before skewing, between a first contact point of the roller at which the roller contacts the first side surface when the roller is skewed toward one side and the first side surface, Y2 represents a clearance, before skewing, between a second contact point of the roller at which the roller contacts the second side surface when the roller is skewed toward the one side and the second side surface, and X represents a difference between the radius of a first imaginary circle passing through the first contact point and the radius of a second imaginary circle passing through the second contact point.

A rolling-element bearing cage includes a plurality of pockets each configured to receive a rolling element, and retaining elements associated with each of the plurality of pockets, each of the retaining elements being configured to secure the rolling elements against falling out of the pockets in a radially inward direction while permitting the rolling elements to be inserted into the pockets in a radially outward direction.

In the tapered roller bearing, at least any one of an outer ring, an inner ring, and a plurality of tapered rollers includes a nitrogen enriched layer. An oil retaining hole is provided in a larger annular portion of a cage. A value of a ratio R/R.sub.BASE is not smaller than 0.75 and not greater than 0.87 where R represents a set radius of curvature of a larger end face of the tapered roller and R.sub.BASE represents a distance from a point which is an apex of a cone angle of the tapered roller to a larger flange surface of the inner ring. A ratio R.sub.process/R is than not lower 0.5 where R.sub.process represents an actual radius of curvature after grinding of the larger end face of the tapered roller and R represents a set radius of curvature.

Provided is a tapered roller bearing (1) subjected to a thrust load and a radial load from a rotation axis (JX). The tapered roller bearing (1) comprises: a plurality of rollers (50) arranged radially between a pair of raceway surfaces (2a, 3a) tilted to one side relative to a plane (P1) perpendicular to the rotation axis (JX); and a retainer (4) disposed between the pair of raceway surfaces (2a, 3a) and having a plurality of pockets (41) for containing the rollers (50). Each of the rollers (50) has: a truncated circular conical roller body (51) having a diameter gradually increasing from the inner side toward the outer side in a radial direction (DD); and a circular conical roller outer section (52) continuous with the outer side of the roller body (51) in the radial direction (DD) and tapered toward the outer side in the radial direction (DD). The inner sides of the rollers (50) in the radial direction (DD) are shaped to conform to the shape of the inner walls of the pockets (41) and are not rotatably supported by the pockets (41), and the outer sides of the rollers (50) in the radial direction (DD) are in point-contact with the inner walls of the pockets (41).

An inner ring unit includes an inner ring, a plurality of tapered rollers, and a cage having an annular shape. The cage includes a plurality of cage bars. The cage includes a stopper portion that is provided to protrude from an axial intermediate portion of the cage bar in the circumferential direction of the cage and configured to hinder the tapered rollers from falling off toward a radially outer side by bringing an axial intermediate portion on an outer peripheral surface of each tapered roller housed in a pocket into contact with the stopper portion. The axial intermediate portion on the outer peripheral surface of the tapered roller is a portion that is disposed on a one axial side and on the radially outer side of the tapered roller with respect to the center of gravity of the tapered roller.

A tapered roller bearing includes an inner ring, an outer ring, a plurality of tapered rollers, and an annular cage. The annular cage includes a small-diameter annular portion, a large-diameter annular portion, and a plurality of cage bars that couple the small-diameter annular portion and the large-diameter annular portion together. The cage bar has a first facing surface that faces the outer peripheral surface of the tapered roller that is housed. The first facing surface includes a large-diameter-side facing surface, a small-diameter-side facing surface arranged farther away from the outer peripheral surface of the tapered roller than the large-diameter-side facing surface, and an intermediate facing surface inclined gradually away from the outer peripheral surface of the tapered roller with increasing distance from the large-diameter-side facing surface to the small-diameter-side facing surface.

A cage for a tapered roller bearing is provided which includes a large-diameter-side annular portion circumferentially extending along the large end surfaces of a plurality of tapered rollers; a small-diameter-side annular portion circumferentially extending along the small end surfaces of the tapered rollers; and a plurality of pillars coupling together the large-diameter-side annular portion and the small-diameter-side annular portion. The large-diameter-side annular portion has large-diameter-side pocket surfaces opposed to the large end surfaces of the respective tapered rollers. The large-diameter-side pocket surfaces include oil retaining holes in the form of blind holes. Lubricating oil is introduced into the oil retaining holes and retained therein by capillary action.

A roller retainer cage for a roller thrust bearing, including a first cage half with an annular portion, a first flange extending axially from an inner peripheral edge of the annular portion and a second flange extending axially from an outer peripheral edge of the annular portion, a second cage half including an annular portion, a first flange extending axially from an inner peripheral edge of the annular portion and a second flange extending axially from an outer peripheral edge of the annular portion, wherein the first flange of the first cage half is disposed radially-outwardly of the first flange of the second cage half, the second flange of the first cage half is disposed radially-inwardly of the second flange of the second cage half, and the first cage half is comprised of a through-hardened metal.