A thrust roller bearing cage (11) a thrust roller bearing (20) and a plurality of pockets (21) accommodating rollers (13). The thrust roller bearing cage (11) includes: a radially outer area bent portion (41) formed by bending an area located radially outside the pockets (21) inward in a radial direction; and projecting portions (44) that are formed in a tip end of the radially outer area bent portion (41) and project inward in the radial direction so as to contact end faces (16) of the rollers (13) accommodated in the pockets. Radially outer edges (21a) of the pockets (21) are located radially outside base end parts (44a) of the projecting portions (44).

The present invention relates to a bearing shaft provided with an outer peripheral surface that includes a raceway surface (side surface) on which a rolling element rolls. The bearing shaft is made of steel containing carbon of 0.7% or more. The raceway surface is formed with a nitrogen-enriched layer. The absolute value of compressive residual stress in the surface of the nitrogen-enriched layer (i.e., the surface of a hardened layer which is formed on the side surface of the bearing shaft by shot peening) is 600 MPa or more and 1700 MPa or less. Thereby, it is possible for the present invention to prolong the operation life of a bearing.

A thrust roller bearing includes rollers arranged in a radial manner, an annular cage that retains the rollers such that the rollers are rollable, an annular outer race located on one side of the cage in an axial direction of the cage and having a first raceway on which the rollers roll, and an annular inner race located on the other side of the cage in the axial direction and having a second raceway on which the rollers roll. At least one of the first raceway and the second raceway has a Vickers hardness that is greater than or equal to 800 and less than or equal to 950. The outer circumferential surface of each of the rollers has a Vickers hardness that is greater than or equal to 697 and less than 800.

A thrust roller bearing cage (11) is a cage (11) provided to a thrust roller bearing and having a plurality of pockets (21) that house needle rollers (13). The cage (11) includes projections (44) that are formed by bending a radially outer area of the cage (11) inwardly along the radius and that project inwardly along the radius toward a radially outer area of the pockets (21) to make contact with end faces (16) of the rollers (13). The projections (44) have corners (45) that make contact with the end faces (16) of the rollers (13). The corners (45) are press-flattened.

A thrust roller bearing cage (11) of the present invention is included in a thrust roller bearing (20) and includes a plurality of pockets (21) accommodating rollers (13). The thrust roller bearing cage (11) includes: a radially outer area bent portion (41) formed by bending the cage (11) inward in a radial direction along an annular groove formed at a position radially outside the pockets (21); and projecting portions (44) that are formed in a tip end of the radially outer area bent portion (41) at positions aligned with the pockets (21) and project inward in the radial direction beyond radially outer edges of the pockets (21) so as to contact end faces (16) of the rollers (13) accommodated in the pockets (21). A trace (29) of the groove is left at a position along which the cage is bent.

A thrust roller bearing cage (11) of the present invention is included in a thrust roller bearing (20) and includes a plurality of pockets (21) accommodating rollers (13). The thrust roller bearing cage (11) includes: a radially outer area bent portion (41) formed by bending an area located radially outside the pockets (21) inward in a radial direction to a tilt angle of less than 45; and projecting portions (44) that are formed in a tip end of the radially outer area bent portion (41) at positions aligned with the pockets (21) and project inward in the radial direction beyond radially outer edges of the pockets (21) so as to contact end faces (16) of the rollers (13) accommodated in the pockets (21).

An axial rolling bearing unit includes a first annular axial bearing washer, a second annular axial bearing washer, a bearing cage formed from a sheet metal material, and rolling elements arranged between the first annular axial bearing washer and the second annular axial bearing washer. The bearing cage includes an inner radial edge rim extending in an axial direction, and an outer radial edge rim extending in the axial direction. The rolling elements are radially guided by the inner radial edge rim and the outer radial edge rim. A one of the inner radial edge rim or the outer radial edge rim has a double-rim design with an end-side bend extending in a direction opposite to the axial direction, and the end-side bend has a first distal end section that holds the first annular axial bearing washer in a form-fitting manner.

A cage for a radial bearing assembly with rolling elements is provided. The cage includes a first and second rims, and webs extend between the rims to define pockets that receive rolling elements. Each of the webs includes first and second rolling element guide surfaces that face a first adjacent one of the pockets and third and fourth guide surfaces that face a second adjacent one of the pockets. These guide surfaces are located at a pitch circle adapted to coincide with a centerline of the rolling elements located in the pockets. The webs have first and second radially inner retention tabs that respectively face the first and second adjacent ones of the pockets. The first retention tab is located axially between the first and second guide surfaces and the second retention tab is located axially between the third and fourth guide surfaces. The retention tabs are located radially inside the pitch circle.

A rolling-element bearing cage or segment configured to guide at least one rolling element includes a first circumferential ring connected to a second circumferential ring by a plurality of axially extending bridges. A first one of the bridges includes a first axial portion that has a cross-section perpendicular to the axial direction and a cross sectional area and a peripheral length. The peripheral length of the cross section of the first axial portion is greater than a peripheral length of a smallest rectangle bounding the cross section.

A thrust roller bearing cage (11) of the present invention is included in a thrust roller bearing (20) and includes a plurality of pockets (21) accommodating rollers (13). The thrust roller bearing cage (11) includes: a first cylindrical portion (36) extending in a direction of a rotation axis (12); a first disc portion (31) continuous with the first cylindrical portion (36) and extending in a radially outward direction; and a second cylindrical portion (37) continuous with the first disc portion (31) and extending in the direction of the rotation axis (12). The first cylindrical portion (36), the first disc portion (31), and the second cylindrical portion (37) are formed in an area located radially inside the pockets (21). The first disc portion (31) has a through hole (53).