An outer ring case includes an annular guide groove housing an end of each of a plurality of inner rollers. A groove width representing a radial length of the guide groove is greater than a diameter of each inner roller. A radius representing a distance from a bearing axis to an inner wall face of the guide groove that is radially outer is smaller than a distance from the bearing axis to an axial center of each of rollers plus a radius of each inner roller.

The present invention provides a bearing device for vehicle wheel reducing the occurrence of abnormal heat generation caused by metal contact and enhancing anti-seizing properties. Each of the tapered rollers 4 has a large diameter-side end surface 41, the inner raceway surface 31, and the large flange part 32. The large flange part 32 includes a chamfered part 32c and a rounded part 32d. The large flange part 32 has a large flange part-side cutout part 34, the large diameter-side end surface 41 of each of the tapered rollers 32 has a tapered roller-side cutout part 43 having a circular shape formed coaxially with the large diameter-side end surface 41, and a clearance of the large diameter-side end surface 41 as viewed from a contact point between the large diameter-side end surface 41 and the guide surface 32a is greater than or equal to 15 μm.

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 on the inner race ring at one axial end, and a flange on the outer race ring at an opposite axial end. At least one of the flanges, or an end of the roller, has a profile including a principal segment with a reference point C defining a contact location between the roller and the flange, the principal segment having a continuously changing radius of curvature, on both sides of reference point C, that decreases as a distance from the reference point C increases.

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 on the inner race ring at one axial end, and a flange on the outer race ring at an opposite axial end. At least one of the flanges, or an end of the roller, has a profile including a principal segment with a reference point C defining a contact location between the roller and the flange, the principal segment having a continuously changing radius of curvature, on both sides of reference point C, that decreases as a distance from the reference point C increases.

A tapered roller bearing is provided in which, in order to prevent a sharp rise in temperature and rotate the bearing smoothly even when the bearing is used under sever lubrication conditions, a grinding undercut has an undercut width A of 0.5 mm or less from a reference point to a large flange surface, the reference point being the intersection point of the imaginary line extending from the generatrix of the raceway surface of the inner ring toward the grinding undercut, and the imaginary line extending from the generatrix of the large flange surface toward the grinding undercut.

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 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 motor including a rotor, a first arm, a mount, a stator, a first bearing, and a second bearing. The motor is configured to rotate the rotor. The mount connected to the first arm. The stator coupled to the mount. The first bearing located between and connecting the rotor to the stator. The second bearing located between and connecting the rotor to the mount. The first arm prevents movement of the stator and the mount.

A follower bearing 1 includes: an inner member 10 including a first body 50 and a flange 52; an outer ring 20; a plurality of rolling elements 40; and a first sealing member 30A including an annular first portion disposed between an outer peripheral surface 52A of the flange 52 and a first surface 22A and at least partially forming a sealing structure between the first portion and the outer ring 20. The first portion has an outer diameter that gradually increases toward a first end surface 52B at an end opposite to a first rolling surface 51A of the flange 52 in an axial direction.

A low clearance, high load capacity roller bearing that includes a cylindrical outer race with a set of non-helical grooves formed on its inside surface that mesh with teeth formed on the outside surface of a plurality of rotating rollers longitudinally and axially aligned inside the outer race. Located inside the rollers are two cylindrical inner race pieces each with non-helical outer grooves configured to mesh with the teeth on the rollers. The rollers are longitudinally aligned and evenly spaced apart inside the outer race and outside the inner race assembly by two retainer plates. The two inner race pieces are separated by a uniform circular gap in which a circular shim is disposed. Different lengths of inner race pieces may be used to create different gap widths needed to reduce the clearance or to pre-load the bearing. Shims with different widths slightly larger or smaller than the gap are placed in the gap.