A transmission unit includes a transmission housing, a transmission element rotatably accommodated in the transmission housing, a bearing seat, and an angular contact ball bearing accommodated in the bearing seat, for mounting the transmission element, as well as a double-row angular contact ball bearing having: an inner bearing ring; a first inner concave rolling element raceway formed in an outer peripheral region of the inner bearing ring; a second inner concave rolling element raceway axially offset to the first inner rolling element raceway and formed in the outer peripheral region of the inner bearing ring; an outer bearing ring; a first outer concave rolling element raceway formed in an inner peripheral region of the outer bearing ring; a second outer concave rolling element raceway axially offset to the first outer rolling element raceway and formed in the outer bearing ring; a first ball-cage assembly with first balls which are accommodated in a first track space extending between the first inner rolling element raceway and the first outer rolling element raceway; and a second ball-cage assembly with second balls which are accommodated in a second track space extending between the second inner rolling element track and the second outer rolling element track. In this way, the central tracks of the two ball-cage assemblies adopt certain axial and radial relative positions.

A bearing device for a vehicle wheel, which has an increased number of balls and in which the ease of mounting the balls is increased. The bearing device is configured such that each of the columns (7b) of the retainer (7) is provided with latch sections (7e) protruding toward adjacent columns (7b) and with cutouts. The front ends of the latches (7e) are located within an annular range having a radial width R1 defined between the outer peripheral circle of a ball (8) and a reference imaginary circle C1 having a diameter D1 centered on the center of the ball (8).

A bearing grease includes a base oil and a thickener, and the base oil includes mineral oil and poly-α-olefin. The poly-α-olefin may be a blend of poly-α-olefin having a kinetic viscosity higher than that of the mineral oil and poly-α-olefin having a kinetic viscosity equal to or lower than that of the mineral oil, and the kinetic viscosity of the base oil at 40° C. is in a range of 40 through 90 mm.sup.2/s. The amount of the poly-α-olefin by mass in the base oil is greater than the amount of the mineral oil by mass in the base oil. The worked penetration of the grease is in a range of 200 through 250. The grease reduces flying grease and outgas and has superior low-temperature characteristics.

A ball bearing cage has a radially encircling, annular body, on which in the circumferential direction, substantially evenly distributed, axially projecting webs having a predefinable axial length are arranged. The webs form a plurality of axially open ball pockets on one side for accommodating a corresponding number of balls having a predefinable ball diameter. At least for one web, a guide section is formed to bring same into an engagement with a running groove of a ball bearing ring. The axial length of the webs corresponds to at least the ball diameter. There is also described a ball bearing having such a ball bearing cage.

A rolling bearing includes: an inner ring; an outer ring; a plurality of rolling elements provided between an inner ring raceway and an outer ring raceway; and a cage that holds the rolling elements at intervals in a circumferential direction. The cage includes an annular portion provided in a first axial direction with respect to the rolling elements, and a plurality of cage bars provided to extend in a second axial direction from the annular portion. The annular portion includes a contact surface that makes sliding contact with a shoulder portion. The cage bars each include a first projecting portion and a second projecting portion. The second projecting portion covers a part of the inner ring raceway on a side of the shoulder portion.

A rolling bearing includes an inner ring, an outer ring, a plurality of balls, and a cage that holds the balls. The cage includes an annular portion and a plurality of cage bars. Each of the balls is received a pocket between each pair of cage bars that is adjacent in the circumferential direction. A portion of the pocket in a second axial direction opens with a dimension that is smaller than a diameter of the balls. The cage bar includes a flat surface that is continuous with an inner peripheral surface of the annular portion, and an inclined surface that extends away from the inner ring toward the second axial direction from the flat surface.

A rolling bearing includes an inner ring, an outer ring, a plurality of rolling elements, and a cage. The cage includes an annular body, a plurality of cage prongs, and guide portions placed inward of the cage prongs in the radial direction of the cage such that the guide portions extend from a radially inner part of the annular body toward a second side in the axial direction of the cage, the guide portions being configured to position the cage by making contact with an inner ring raceway. The cage has a groove so as to connect pockets adjacent to each other in the circumferential direction, the groove being configured such that lubricant is present in the groove and a groove width of the groove is increased in the radial direction in the center of the groove in the circumferential direction.

A rolling bearing includes an inner ring, an outer ring, a plurality of rolling elements, and a cage. The cage includes an annular body placed closer to the first side in the axial direction than the rolling elements, and a plurality of cage prongs provided to extend to the second side in the axial direction from the annular body. The cage prong includes a lack portion provided from the first side to the second side in the axial direction such that the lack portion is opened to the second side in the axial direction and along the radial direction. The cage prong includes a pair of cage prong bodies such that the cage prong bodies are provided on both sides of the lack portion in the circumferential direction and make contact with a corresponding one of the rolling elements, and a stiffening rib is provided between the cage prong bodies.

A ball bearing includes an inner ring, an outer ring, a plurality of balls rollably provided between the inner ring and the outer ring, and a cage configured to hold the plurality of balls at equal intervals in a circumferential direction. The cage includes a plurality of pockets configured to hold the balls. The plurality of pockets include at least two types of pockets including a first pocket and a second pocket. A gap on each of an outer circumferential surface side and an inner circumferential surface side of the cage between the ball and an inner circumferential surface of the second pocket is larger than a gap on each of the outer circumferential surface side and the inner circumferential surface side of the cage between the ball and an inner circumferential surface of the first 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.