A ball bearing unit for a turbocharger according to an embodiment includes: an outer ring, a first inner ring, a second inner ring, a first machined retainer and a second machined retainer. The outer ring has an inner peripheral surface provided with an outer ring raceway surface at one end side and an outer ring raceway surface at another end side. At least one of the first machined retainer and the second machined retainer includes a plurality of pockets that hold the plurality of balls in a rollable manner in a circumferential direction. Each of the pockets has a diameter of equal to or more than 1.03 times and equal to or less than 1.07 times of a diameter of the balls.

A cage for a roller bearing is provided. The cage has a ring-shaped base body with a plurality of pockets for receiving rolling elements. The base body is formed by two side rings arranged in a defined axial distance and by a plurality of pocket elements, which are located between the side rings. Each pocket element has two face sides designed for contacting a rolling element. The connection between the pocket element and each of the side rings is established by at least one beam joined with one of the side rings and the pocket element. The beam is a positive substance joined with one of the side rings and the pocket element and has a ring-shaped or elliptical cross section in a section perpendicular to the longitudinal extension of the beam.

Angular contact ball bearings are disclosed. In one example, the angular contact ball bearing may include an inner ring having an inner ring raceway and an outer ring having an outer ring raceway. A plurality of balls may roll on the inner and outer raceways. A cage may guide the plurality of balls in a plurality of closed pockets, wherein each ball is accommodated in one of the closed pockets. The bearing may include a plurality of projections, wherein each projection extends radially toward the raceway of the outer ring between every two adjacent, closed pockets. The cage may be guided on the outer ring raceway by the projections.

A method for producing a cage having a body with multiple pockets for rolling elements, the method providing: a) defining a cage basis geometry that provides a radial outer and/or inner surface for contacting a bearing ring and multiple surfaces of the pockets for contacting the rolling elements; b) defining a part of the radial outer and/or inner surfaces as being unalterable surfaces; c) calculating the cage stress distribution when applying a defined stress force from a mathematical model; d) defining cage volume sections where the stress is below a defined threshold; e) removing a part of the volume sections defined according to step d) taking into account the unalterable surfaces according to step b) and the surfaces of the pockets that are unalterable surfaces; f) defining the cage geometry with the removed volume sections; g) manufacturing the cage according to the geometry as defined according to step f).

An angular contact ball bearing cage includes a plurality of pockets. At least one (imaginary) sectional plane extends through a first pocket, and the sectional plane is located such that an axis of rotation of the angular contact ball bearing cage lies in the sectional plane. The axis of rotation is an axis about which the angular contact ball bearing cage is configured to rotate in operation. A geometric centerpoint of the first pocket lies in the sectional plane, and an intersection of the sectional plane and a side of the first pocket includes a first portion that is not linear and that does not lie on the surface of a cone.

A ball bearing unit for a turbocharger according to an embodiment includes: an outer ring, a first inner ring, a second inner ring, a first machined retainer and a second machined retainer. The outer ring has an inner peripheral surface provided with an outer ring raceway surface at one end side and an outer ring raceway surface at another end side. At least one of the first machined retainer and the second machined retainer includes a plurality of pockets that hold the plurality of balls in a rollable manner in a circumferential direction. Each of the pockets has a diameter of equal to or more than 1.03 times and equal to or less than 1.07 times of a diameter of the balls.

A ball bearing includes an inner ring including an inner ring raceway surface on an outer periphery, an outer ring including an outer ring raceway surface on an inner periphery, a plurality of balls arranged between the inner ring raceway surface and the outer ring raceway surface, and a retainer including a plurality of pocket holes which respectively store the plurality of the balls, and arranged between the inner ring and the outer ring. Grease is sealed between the inner ring and the outer ring. The inner periphery of the outer ring is contacted with outer peripheral surface of the retainer so as to guide the retainer. The inner periphery of the outer ring includes a grease storage groove which communicates with the outer ring raceway surface, only on one side in an axial direction of the outer ring with respect to the outer ring raceway surface.

A cage for a roller bearing is provided. The cage has a ring-shaped base body with a plurality of pockets for receiving rolling elements. The base body is formed by two side rings arranged in a defined axial distance and by a plurality of pocket elements, which are located between the side rings. Each pocket element has two face sides designed for contacting a rolling element. The connection between the pocket element and each of the side rings is established by at least one beam joined with one of the side rings and the pocket element. The beam is a positive substance joined with one of the side rings and the pocket element and has a ring-shaped or elliptical cross section in a section perpendicular to the longitudinal extension of the beam.

In a copper alloy machined cage for a thrust ball bearing, an inside surface of a pocket includes a cylindrical surface, a support surface which is continuous with the cylindrical surface and contacts a ball in an axial direction, and two protruding portions which are formed at an equal interval in a circumferential direction of the pocket, at a ball insertion side of the pocket which is opposite to the support surface in the axial direction and protrude from the cylindrical surface. The protruding portions prevent falling out of the ball from a ball insertion side opening of the pocket and are either elastically deformed or elastic-plastically deformed by the ball during insertion of the ball into the pocket.

A bearing unit includes a radially outer ring, a radially inner ring, and a retention cage configured to retain a plurality of rolling bodies between the radially outer ring and the radially inner ring. The retention cage includes a one-piece annular body having a plurality of radially extending pockets each configured to retain one of the plurality of rolling bodies, and each of the plurality of pockets is bounded by a pocket surface. The pocket surface includes a plurality of convex portions and a plurality of concave portions and is bounded by an inner imaginary cylinder and a concentric outer imaginary cylinder. The convex portions are tangent to or extend in part along the inner imaginary circle, and the concave portions are tangent to or extend in part along the outer imaginary circle.