The invention has an object of providing grease reduced in an amount of the flying grease and an amount of the outgas, and superior in low-temperature characteristic, an antifriction bearing using the grease, an antifriction bearing device, and an information recording/reproducing device. A grease includes a base oil, and a thickener, the base oil includes mineral oil and poly-α-olefin, the poly-α-olefin is higher in mass than the mineral oil, the poly-α-olefin includes poly-α-olefin higher in kinetic viscosity than the mineral oil, the kinetic viscosity of the base oil at 40° C. is in a range of 40 through 90 mm.sup.2/s, and worked penetration is in a range of 200 through 250. Further, an antifriction bearing, an antifriction bearing device, and an information recording/reproducing device use the grease.

A cage for a bearing, including: a first annular segment; a second annular segment located radially inwardly of the first annular segment; a vane connected to the first annular segment and to the second annular segment and including a first axial end facing at least partly in a first axial direction parallel to an axis of rotation of the cage and a second axial end facing at least partly in a second axial direction, opposite the first axial direction, the second axial end off-set from the first axial end in a circumferential direction around the axis of rotation; and a curved surface connected to the first annular segment and the second annular segment and arranged to retain a ball of the bearing. The first annular segment, the second annular segment, the vane, and the curved segment define a channel passing through the cage.

There is provided a ball bearing having a cage and balls held in the cage, the balls arranged one behind the other at a distance from one another in a circumferential direction about an axis of rotation of the ball bearing. The cage assembled from at least two cage parts joined to one another in a bonded manner and completely enclose the balls in a circumferential surface extending around the axis of rotation. A first cage part designed as a snap cage having axial webs projecting in the direction of the axis of rotation from a closed base ring and form ball pockets therebetween them, the first cage part encloses the balls along their outer circumference by more than 180°, holds the balls positively while forming an undercut and limits displacement of the balls within the circumferential surface in the direction of the at least one other second cage part.

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.

Provided are a bearing and a medical device in which a gap is secured between an inner ring and an outer ring, and the gap can be used as a flow path for a fluid or an object. A bearing having a plurality of rolling elements between an inner ring and an outer ring is provided with a raceway surface on which the rolling elements roll on the outer ring and receiving portions for rotatably accommodating the rolling elements at a position of the inner ring facing the raceway surface.

There is provided a ball bearing having a cage and balls held in the cage, the balls arranged one behind the other at a distance from one another in a circumferential direction about an axis of rotation of the ball bearing. The cage assembled from at least two cage parts joined to one another in a bonded manner and completely enclose the balls in a circumferential surface extending around the axis of rotation. A first cage part designed as a snap cage having axial webs projecting in the direction of the axis of rotation from a closed base ring and form ball pockets therebetween them, the first cage part encloses the balls along their outer circumference by more than 180° , holds the balls positively while forming an undercut and limits displacement of the balls within the circumferential surface in the direction of the at least one other second cage part.

A bearing cage for a rotor bearing of a turbomolecular pump. The bearing cage includes a plurality of bearing pockets each of which, in use, houses a bearing ball such that the bearing ball operably engages an inner race and an outer race of the rotor bearing. Each bearing pocket of the bearing cage has a primary chamber for housing the bearing ball and each bearing pocket further includes a sump.

A bar portion is formed so that an outer circumferential surface on a tip portion side is located on an inner diameter side with respect to an outer circumferential surface of a main portion. On an inner diameter side of a cage, lightened portions obtained by notching in an axial direction from an axial side surface of the main portion are formed separately at positions of the respective bar portions in a circumferential direction. Each lighting portion is formed separately from a surface of a pocket and an axially outer surface of the bar portion formed between a pair of claw portions. An axial dimension T1 of a wall portion formed between an axially outer surface of the bar portion and an inner wall surface of the lightened portion is greater than an axial dimension T2 of the main portion on a bottom portion of the pocket.

A bearing cage is used for accommodating the rolling elements of a rolling bearing; wherein, the bearing cage comprises an annular cage base; when the bearing cage is inserted and installed in the rolling bearing, there is a first circumferential radial clearance between an outer circumferential surface of the cage base and an inner circumferential surface of an outer ring shoulder of an outer ring, and a second circumferential radial clearance between an inner circumferential surface of the cage base and an outer circumferential surface of an inner ring shoulder of an inner ring; the first circumferential radial clearance is smaller or larger than the second circumferential radial clearance. A rolling bearing comprises the bearing cage as described above.

A cage for retaining one or more rolling bodies of a bearing unit, the cage including a rib having a plurality of spherical concave surfaces, and a plurality of circumferentially spaced tenons extending from a first axial side of the rib, each tenon of the plurality of tenons including a plurality of spherical concave surfaces and an armature defining a box shape, the armature including a plurality of first portions resting on a first plane and a plurality of second portions resting on a second plane, each first portion of the plurality of first portions alternating circumferentially with each second portion, and the spherical concave surfaces of the rib defining, with the spherical concave surfaces of the tenons, a plurality of spherical cavities to hold each rolling body of the row of rolling bodies in place.