A retainer is rotationally driven about a axis of a ball bearing, and convex areas having pockets provided therein along a ball pitch circle of the retainer and concave areas between adjacent pockets is detected by a sensor. Grease is discharged according to phases of the convex areas and concave areas in the rotationally driven retainer from a dispenser having grease discharge ports arranged to face an annular space.

A ball bearing is provided which includes inner and outer races each having a raceway groove; balls; and a retainer made of a synthetic resin, and in which abnormal noise is reduced. Either the raceway groove of the inner race, or each of the raceway grooves of the inner race and the outer race has a radius of curvature which is 104% or more and 109% or less of the radius of each of the balls.

A retention system for a bearing member includes a sleeve member and a retention member. The retention system includes an inner shoulder adapted to limit movement of the bearing member in at least one of a first axial direction and a second axial direction relative to the bore. The retention system includes an outer shoulder adapted to limit movement of at least one of the sleeve member and the retention member in at least one of the first axial direction and the second axial direction relative to the bore. The retention system includes a plurality of fasteners adapted to limit movement of each of the sleeve member and the retention member in at least one of the first axial direction and the second axial direction relative to the bore. Each of the sleeve member and the retention member is adapted to limit contact of the bearing member with the bore.

A method of lubricating a main bearing of a wind turbine, the method comprising providing the main bearing. The main bearing comprises a main bearing housing having one or more pre-existing lubrication ports, an outer race, an inner race radially disposed inwardly from the outer race, and a first row of roller bearings and a second row of roller bearings. The first and second rows of roller bearings are radially disposed between the inner race and the outer race. The first row of roller bearings is axially disposed on the upwind side of the second row of roller bearings. The method includes forming one or more alternate lubrication ports in the main bearing housing. The alternate lubrication ports are configured to deliver a lubricant between the first row of roller bearings and the second row of roller bearings. The method includes supplying the lubricant to the alternate lubrication ports.

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 lubricatable ball spline device includes a ball spline shaft, a ball nut slidably sleeved on the ball spline shaft and having oil guide holes, a linear bearing unit mounted between the ball spline shaft and the ball nut, a bearing ring rotatably sleeved on the ball nut and having an oil supplying hole, a positioning portion disposed between the bearing ring and the ball nut, and an oil passage corresponding to the oil supplying hole. The oil supplying hole, the oil passage, an oil storage space of the positioning portion and any one of the oil guide holes cooperatively form a continuous oil path.

A retainer for a bearing is entirely formed into an annular shape and has a crown shape. The retainer includes pockets which are formed at a plurality of locations in a circumferential direction of the retainer and are each opened on a radially outer side and a radially inner side. The pockets retain balls being rolling elements so that the balls are rollable. A grease flow-in passage is provided between an inner surface of each of the plurality of pockets and each of the balls.

A ball bearing is provided which includes inner and outer races each having a raceway groove; balls; and a retainer made of a synthetic resin, and in which abnormal noise is reduced. Either the raceway groove of the inner race, or each of the raceway grooves of the inner race and the outer race has a radius of curvature which is 104% or more and 109% or less of the radius of each of the balls.

A tapered roller bearing includes an inner ring, an outer ring, a plurality of tapered rollers, and an annular cage that holds the tapered rollers. The cage has a small annular portion positioned toward the axially first side with respect to the tapered rollers, a large annular portion positioned toward the axially second side with respect to the tapered rollers, and a plurality of cage bars that couples the small annular portion and the large annular portion together, and the cage is enabled to come into contact with an inner peripheral surface of the outer ring so that the contact allows the cage to be positioned in a radial direction. The small annular portion is provided with introduction channels through which lubricant is enabled to be introduced from a bearing exterior on the axially first side into an annular space formed between the inner and outer rings.