Bearing unit provided with at least one ring of rolling bodies and, for retaining the rolling bodies, at least one retaining cage which has a cage bar, a plurality of circumferentially spaced cage arms that extend from one side of the cage bar, and a plurality of partially spherical cavities for retaining the rolling bodies; contact points between the rolling bodies and the cage being positioned in the vicinity of a polar region of each rolling body. The minimum number of contact surfaces for containing the rolling bodies in the direction of rotation of the bearing and ensuring contact only in the polar region is equal to two for each rolling body, namely one upper contact surface and one lower contact surface.

The present invention provides bearing cage retainer for a rolling element rotor bearing in a vacuum pump. The bearing cage retainer being configured to have an operational arrangement in which, at the maximum longitudinal axial displacement limit of the outer race in the direction of the retainer, the bearing cage retainer is disengaged from the bearing cage, and a failure configuration characterised by the dislocation of the bearing cage by a longitudinal axial displacement of the bearing cage relative to the outer race in the direction of the retainer and in which the bearing cage retainer engages said bearing cage and the bearing cage maintains the separation of the rolling elements within the bearing.

A rolling bearing, wherein the rolling elements are loaded, equipped with a cage separating the rolling elements, wherein at least one groove is situated on the bearing race on which the rolling elements travel, wherein edges of the groove are positioned at an angle from 4.5 to 80 in relation to the movement direction of the rolling elements, and in the cage, holes for the rolling elements are made askew so that the angle between a straight line connecting the cage centre with the centre of the hole for the rolling element and a tangent to the rolling element in the contact point of this element with the cage has a value >arc tg , where is the sliding friction coefficient of mating of the rolling element material with the cage material.

A ball bearing retainer holds balls disposed between an inner ring and an outer ring, in pockets formed at a plurality of portions, in a circumferential direction, of an annular body. The annular body includes: annular parts disposed on both sides in an axial direction; and pillar parts that are disposed at a plurality of portions in the circumferential direction and that connect between the annular parts. The pockets are formed by the annular parts and the pillar parts adjacent to each other in the circumferential direction, and allow ball guide. First contact portions of the pillar portions, which contact portions contact with the balls in the circumferential direction, are formed by first planes that extend along the axial direction, and the balls are guided by the first planes.

A retainer of an outer ring guide type, includes a retainer guide surface, a relief surface (edge relief groove), and an axial groove. The retainer guide surface is provided on at least one axial end portion of a retainer outer diameter surface and is guided by the outer ring. The relief surface is formed on the retainer outer diameter surface along a circumferential direction, located on an axial center side with respect to the retainer guide surface, and has an outer diameter smaller than that of the retainer guide surface. The axial groove extends from the pockets to an axial end on the retainer outer diameter surface, forms an axial step portion by axially traversing the retainer guide surface, and has a groove bottom on a radial inner side with respect to the relief surface.

A ball cage for ball bearing includes a first race, a second race, a plurality of first ribs equiangularly arranged on the first race with a first curved groove defined between each two adjacent first ribs, and a plurality of second ribs equiangularly arranged on the second race with a second curved groove defined between each two adjacent second ribs. The first ribs are respectively and partially stacked on the second ribs so that each first curved groove is combined with one respective second curved groove to create a respective ball accommodation chamber. Thus, the ball cage can be commonly used for ball bearings lubricated with grease or oil gas to increase the convenience of use.

A bearing cage includes an annular body disposeable between inner and outer rings and having first and second axial ends, inner and outer circumferential surfaces, and a plurality of pockets for retaining rolling elements. The cage includes at least one channel extending axially through the annular body and having a first opening at the first axial end and a second opening at the second axial end. The channel(s) are each configured to direct liquid to flow axially through the bearing when the cage rotates about the centerline. Alternatively or additionally, the cage includes at least one elongated projection extending radially inwardly from the inner circumferential surface or radially outwardly from the outer circumferential surface and extending axially between the first axial end and the second axial end. The projection(s) are each configured to direct liquid to flow axially through the bearing when the cage rotates about the centerline.

A ball bearing includes an inner ring, an outer ring, a plurality of balls rollably disposed between an inner ring raceway surface of the inner ring and the outer ring raceway surface of the outer ring, and a cage in which pockets rollably holding the balls are formed at intervals in a circumferential direction. An inclination angle of a cylindrical surface of each of the pockets is set more than 0 and less than a contact angle of the ball bearing, the cylindrical surface and a corresponding ball are in contact with each other at an inner side in a cage thickness direction relative to a position where a rotation axis of the ball intersects with the cylindrical surface, and a space is formed at a portion from a contact position to a circumferential surface of the cage on a side closer to the intersection position.

A bearing unit may be provided with at least one row of rolling bodies and at least one cage for retaining the rolling bodies. The at least one rolling cage may include a base rib; a plurality of fingers spaced circumferentially and extending at least from one side of the base rib; and a plurality of partially spherical cavities for holding the rolling bodies, each cavity being defined by the partially spherical concave surfaces of a pair of fingers of the plurality of fingers and of the base rib. The rolling bodies and the cages are in contact with each other via a plurality of protrusions formed on the partially spherical concave surfaces of the fingers and of the base rib. At least one lateral protrusion may be formed along the surface of each finger of the plurality of fingers of the retaining cage.

Cages for ball bearings are disclosed. In one example, a ball bearing cage includes two side rings interconnected by webs. Rolling element pockets, each of which may have a square basic shape with rounded corners, may be formed in a circumferential direction between the webs. The side rings, together with the webs, may form a guide contour of each rolling element pocket. The pockets may have four convex side contours between the corners thereof, and the side contours may point in a direction opposite to rounded portions in the corners.