According to a crown retainer (11) of a ball guide type, a pocket (9) of the retainer (11) has a straight surface (9a) and a tapered surface (9b) where a ball (7) comes into surface contact therewith. A connection point (9c) between the straight surface (9a) and the tapered surface (9b) is on an inner diameter side of an intersection position (I) between an extension plane (F) of a rolling element equatorial plane and a wall surface of the pocket (9). In a two-dimensional cross section passing through centers (O) of a plurality of balls (7), a distance (P) between the ball (7) and the wall surface of the pocket (9) in the extension plane (F) in a neutral position is smaller than a shortest distance (T) between the tapered surface (9b) and the ball (7) in a direction perpendicular to a straight line (L).

An angular contact ball bearing includes an outer ring having an outer diameter D and a first rolling surface and an inner ring having an inner diameter d and a second rolling surface, and no more than one row of balls between the first rolling surface and the second rolling surface, each of the balls having a diameter D.sub.w. The diameter D.sub.w of the balls, the outer diameter D of the outer ring, and the inner diameter d of the inner ring satisfy the relationship:

[00001]$D_w>0.7*\frac{\left(D-d\right)}{2}$

A double-row self-aligning roller bearing has rollers interposed, in two rows aligned in a bearing width direction, between an inner ring and an outer ring. The outer ring has a spherical raceway surface. Each of the rollers has an outer circumferential surface having a cross-sectional shape that matches the raceway surface of the outer ring. The rollers have lengths equal to each other and maximum diameters equal to each other, and have different distances from centers of the roller lengths to positions at which the maximum diameters are obtained.

A bearing, for supporting a rotation shaft of a rotatable member, capable of being supported by a supporting portion provided with an engaging hole engageable with the bearing includes positioning projections having contact surfaces and bearing projections having sliding surfaces on which an outer peripheral surface of the rotation shaft slides. The positioning projections project from different positions so that between adjacent positioning projections, an outer peripheral surface of the bearing and the inner wall surface of the engaging hole form a gap therebetween. The bearing projections project from different positions so that between adjacent bearing projections, an inner peripheral surface of the bearing and an outer peripheral surface of the rotation shaft form a gap therebetween. With respect to a circumferential direction of the rotation shaft, the positioning projections and the bearing projections are provided at positions different from each other.

A bearing assembly is configured to rotatably support a first machine part in a second machine part and includes first and second rolling-element bearings. The rolling-element bearings are installed in the bearing assembly with an axial preload or an axial clearance. The second machine part includes a first conical abutment surface, and the first rolling-element bearing includes a bearing ring having a second conical abutment surface facing the first conical abutment surface of the second machine part. An intermediate ring is disposed between and abuts the first and second conical abutment surfaces. The bearing ring and the second machine part are metal, and the intermediate ring is formed from a material that has a higher coefficient of thermal expansion than that of the bearing ring and second machine part.

A hub unit that is to be installed on a vehicle is provided with: an outer ring having, on the inner circumferential surface, a first outer raceway surface and a second outer raceway surface that is disposed to the outside of the first outer raceway surface in the vehicle width direction when the hub unit is installed on the vehicle; an inner shaft that is disposed on the inside of the outer ring concentrically with the outer ring and on which a wheel is installed on the outer end in the vehicle width direction; and an inner ring that is press-fitted to the inner shaft on the inner end in the vehicle width direction.

Two hybrid ball bearings and a compressor bearing arrangement with two hybrid ball bearings for a rotatable support of a rotor of the compressor versus a stator of the compressor. The two hybrid ball bearings are arranged face-to-face or back-to-back, are designed with an optimal axial clearance depending on the inner diameter of a ring-shaped inner raceway element one of the hybrid ball bearings respectively a pitch diameter of one of the two hybrid ball bearings for a long bearing life in connection with an optimal compressor operating performance.

A wheel hub bearing unit includes a hub rotatable about an axis and having a flange connectable with a wheel, an inner ball raceway and an inner roller raceway. An outer ring is connectable with the vehicle and disposed about the hub and has an outer ball raceway and an outer roller raceway. A plurality of balls roll upon the inner and outer ball raceways and a plurality of tapered rollers roll upon the inner and outer roller raceways. A contact angle between the balls and the ball raceways has a value between ten degrees and forty degrees. Each line extending through ball inner and outer contact points intersects with a line extending through a roller midpoint circle at a vertex, the vertex being spaced from a midpoint of a spacing line segment between ball and roller pitch circles by an axial distance of no greater than 7.5 millimeters.

A tapered roller bearing (1) is includes an outer ring (2) having an outer ring raceway surface (2a) on the inner peripheral surface thereof, an inner ring (3) having an inner ring raceway surface (3a) on the outer peripheral surface thereof, and a plurality of tapered rollers (4) arranged in a rollable manner between the outer ring raceway surface (2a) and the inner ring raceway surface (3a). A large flange (3b) is formed on an end portion of the inner ring (3) on a large-diameter side of the inner ring, and the inner ring raceway surface (3a) continuously extends to the end face (3c) of the inner ring (3) on a small-diameter side of the inner ring. The contact angle (?) is 37?30 to 50?. In this manner, the tapered roller bearing having high moment rigidity and long life can be provided.

A bearing arrangement for a fluid machinery application employing an axially locating bearing. The axially locating bearing includes: a first angular self-aligning contact bearing arranged next to a second angular self-aligning contact bearing. Each of the first angular self-aligning contact bearing and the second angular self-aligning contact bearing includes a set of rolling elements arranged in a row and interposed between a respective curved inner raceway and an associated curved outer raceway. Each roller is a symmetrical cylindrically-shaped roller having a curved raceway-contacting surface. Each roller is inclined respective to the axial direction of the shaft by a respective contact angle. The rollers support an axial force and a radial force. The axially non-locating bearing position is arranged spaced apart from the axially locating bearing position, as seen in the axial direction. Examples of fluid machinery applications include: a wind turbine, water turbine or a propulsion turbine.