A bearing assembly includes a roller bearing unit, an inner race and an outer race. The roller bearing unit is formed of polycrystalline super-hard material having a mean mass density of at most 4.5 g/cm.sup.3 and a volume-weighted arithmetic mean thermal conductivity of at least 100 W/m.Math.K.

A roller bearing comprises an outer ring, an inner ring, a plurality of rollers arranged between the outer ring and the inner ring, and a plurality of retainer segments having a plurality of column parts extending in a direction along a shaft so as to form a pocket for holding the roller, and connection parts and extending in a circumferential direction to connect the plurality of column parts, and continuously lined with each other in the circumferential direction between the outer ring and the inner ring. The column part is positioned at an circumferential end of the retainer segment. Here, a circumferential outer side end face of the column part positioned at the end is flat, and a circumferential inner side end face of the column part positioned at said end is provided with a recess recessed in the circumferential direction to reduce the thickness of the column part.

A roller bearing comprises an outer ring, an inner ring, a plurality of rollers arranged between the outer ring and the inner ring, and a plurality of retainer segments having a plurality of column parts extending in a direction along a shaft so as to form a pocket for holding the roller, and connection parts and extending in a circumferential direction to connect the plurality of column parts, and continuously lined with each other in the circumferential direction between the outer ring and the inner ring. The column part is positioned at an circumferential end of the retainer segment. Here, a circumferential outer side end face of the column part positioned at the end is flat, and a circumferential inner side end face of the column part positioned at said end is provided with a recess recessed in the circumferential direction to reduce the thickness of the column part.

A spacer device for roller elements of a toroidal roller bearing includes an inner ring with an inner ring raceway and an outer ring with an outer ring raceway. The toroidal roller bearing allows for axial and angular displacement between the inner ring and the outer ring. The spacer device comprises at least one centering element that is arranged to extend in between adjacent roller elements in a longitudinal direction of the roller elements when the spacer device is in use. The at least one centering element is arranged to make contact with at least one of one point or a region of one of the inner ring raceway or the outer ring raceway when the spacer device is in use, whereby the spacer device is centered on the one of the inner ring raceway or the outer ring raceway.

A bearing assembly includes a roller bearing unit, an inner race and an outer race. The roller bearing unit is formed of polycrystalline super-hard material having a mean mass density of at most 4.5 g/cm.sup.3 and a volume-weighted arithmetic mean thermal conductivity of at least 100 W/m.Math.K.

A spacer includes a first surface and a second surface. The first surface and the second surface respectively have two opposite first roller accommodating grooves and two opposite second roller accommodating grooves. The first and second roller accommodating grooves of the first surface correspond to the second and first roller accommodating grooves of the second surface. The spacer defines a reference plane, which is perpendicular to a horizontal direction and passes through a center point of the maximum thickness of the spacer. The horizontal distance from the reference plane to the center of each first roller accommodating groove is different from the horizontal distance from the reference plane to the center of each second roller accommodating groove. By flipping the spacer of the present invention, the spacing of two adjacent rollers can be adjusted. In addition, the present invention further provides a cycloidal reducer with the aforementioned spacer.

An anti-friction radial bearing has an inner track, an outer track, a pair of extension members, load-carrying rolling members, and double coaxial, cylindrical individual spacers. Each of the extension members has an internal cylindrical hoop surface and is securely mounted to at least one of the inner and outer tracks. The rolling members are equidistantly spaced and rotatably engageable with the inner and outer tracks. The spacers are disposed in pure rolling contact at their ends with the internal cylindrical hoop surfaces of the extension members. Each of the spacers is positioned in pure rolling contact between a corresponding adjacent pair of the rolling members.

The invention relates to a rolling bearing, in particular in the form of an open-center large rolling bearing, comprising a large number of rolling elements, which are held between at least two raceways, on which the rolling elements roll, wherein spacers are provided between the rolling elements, which spacers keep the rolling elements spaced apart from each other. According to the invention, at least one of the raceways has, in a center portion, an approximately groove-shaped longitudinal recess, in which support arms provided between the spacers run, which support arms reach around the rolling element between two adjacent spacers and support the adjacent spacers against each other in the running direction of the rolling elements.

Provided is a separator having excellent chemical resistance, impact resistance, and productivity. A bearing retainer (1) is a separator that is interposed between two spheres adjacent to and moving in conjunction with each other for retaining the spheres configured to be movable in conjunction with and apart from each other and is formed from a resin composition containing a fluororesin which is a polymer of a monomer containing vinylidene fluoride as a main component. The bending modulus of elasticity of the resin composition is 1600 MPa or less, and the Charpy impact strength of the resin composition is 26 kJ/m.sup.2 or more.

Provided is a separator having excellent chemical resistance, impact resistance, and productivity. A bearing retainer (1) is a separator that is interposed between two spheres adjacent to and moving in conjunction with each other for retaining the spheres configured to be movable in conjunction with and apart from each other and is formed from a resin composition containing a fluororesin which is a polymer of a monomer containing vinylidene fluoride as a main component. The bending modulus of elasticity of the resin composition is 1600 MPa or less, and the Charpy impact strength of the resin composition is 26 kJ/m.sup.2 or more.