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 tapered roller bearing having a diameter of less than 1.5 m includes an inner ring having at least one inner raceway, an outer ring having at least one outer raceway and at least one set of tapered rollers between the inner ring and the outer ring that are configured to roll on the at least one inner raceway and on the at least one outer raceway about a tapered-roller rotational axis while the tapered roller bearing is configured to rotate about a bearing rotational axis. An angle formed by the bearing rotational axis and the tapered-roller rotational axis is greater than 450 and is preferably between 500 and 55.

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.

A transport-securing unit for retaining a plurality of rollers in a rolling-element bearing cage during transportation may include an annular region and a plurality of axially extending, circumferentially spaced projections extending from the annular region. Also, an assembly of the transport-securing unit, a rolling-element cage and a plurality of rollers in pockets of the rolling-element bearing cage, where the transport-securing unit is formed separately from the rolling-element bearing cage, and where the projections extend inside the cage and limit radially inward movement of the rollers relative to the cage.

A roller bearing includes an inner race ring, an outer race ring, and a roller arranged between and in contact with the inner and outer rings. The bearing has a flange (31,131) on the inner race ring at one axial end, and a flange (21,121) on the outer race ring at an opposite axial end. One of the flanges, and/or an end of the roller, includes at least one principal segment (53,153) intermediate two additional segments (52,152; 54,154). The principle segment is tangentially blended with the two additional segments, and the principle segment has a first curvature that is different from the respective curvatures of the two additional segments. A non-elliptical contact footprint can be obtained by composite profiles at the contact location between the roller end and the mating flange face.

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.

A value of R/R.sub.BASE is not smaller than 0.75 and not greater than 0.87 where R represents a reference radius of curvature of a larger end face of a roller and R.sub.BASE represents a distance from an apex of a cone angle of the roller to a larger flange surface of an inner ring 13. A distance from an outermost surface of at least any one of an outer ring, the inner ring, and a plurality of rollers to a bottom of a nitrogen enriched layer is not shorter than 0.2 mm. A crowning profile is formed on a rolling surface of the roller.

The present disclosure discloses a polymer joining ring for a bearing assembly and is configured to retain a first inner ring and a second inner ring together to the bearing assembly. The polymer joining ring includes an outer surface and an inner surface. The outer surface includes a W or E shaped geometry throughout and includes a pair of flanges extending radially outwards at corners from outer surface, and a semi-circular protrusion extending at middle of the polymer joining ring. The pair of flanges are placed in tapered narrow grooves of the first inner ring and the second inner ring, and the semi-circular protrusion is placed in a triangular shape space produced between the first inner ring and the second inner ring can be tightly connected to each other. The joining ring is made of a polymer material that facilitates ease in assembling and accurate positioning of the inner rings.

A tiltrotor aircraft may be provided and may include a mast assembly, in which the mast assembly may include a mast; a bearing system; a housing; and a housing cap secured to the housing, wherein the bearing system is between the mast and the housing. The bearing system may further include a first bearing assembly including a first inner race, a first outer race, and a plurality of first tapered roller bearings; a second bearing assembly including a second inner race, a second outer race, and a plurality of second tapered roller bearings; an inner spacer and an outer spacer in which the inner and outer spacers are between the first and second bearing assemblies; and a retaining device in which the retaining device and the housing cap provide, at least in part, pre-loading for the first and second bearing assemblies.

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).