RKB Thrust ball and roller bearings
RKB thrust ball bearings are manufactured in two versions: single and double direction. They can carry heavy axial loads, but they cannot take radial loads. The single direction bearings consist of shaft washer, housing washer with flat support surface and ball cage assembly. The bearings are of separable design for a simple mounting of the parts. The double direction thrust ball bearings can take axial loads in both directions. Such a bearing consists of a shaft central washer, two housing washers and two ball cage assemblies. The bearings are of separable design and ball cage assemblies are interchangeable with the corresponding single direction bearings. Thrust ball bearings with sphered housing washer can be used with sphered seating housing to compensate the misalignment between the support surface in the housing and in the shaft. The boundary dimensions of RKB thrust ball bearings in metric size conform to ISO 104:1979 dimensional series 8. They are produced to normal tolerance class in accordance with ISO 199:1997. RKB big size thrust ball bearings are normally fitted with machined brass cage (suffix M). Machined steel cage (suffix F) is also available. RKB cylindrical roller thrust bearings are generally used to take over heavy pure axial loads, to carry shock loads and to be stiff into a little axial space with simple design. They are manufactured for the axial support of a shaft in one direction and are available as single or multi rows of rollers. Double direction cylindrical roller thrust bearings can be easily obtained with assembly of the standard roller cage and washers together with an appropriately designed intermediate washer. If the support shaft shoulder is heat treated and ground, it can be used as a raceway for the roller cage assembly.
In case of more rows, the rollers have various lengths and are alternatively mounted. To avoid side friction, one of the side of the roller can be crown profiled. The boundary dimensions of RKB cylindrical roller thrust bearings conform to ISO 104:1979. Angular misalignment between shaft and housing is not permitted. In order to guarantee a proper arrangement of the rolling parts for the satisfactory operation, the cylindrical roller thrust bearings have always to be submitted to a given minimum load, specially when high speeds, high accelerations or rapid changes of load directions are involved. Both machined brass and steel cages are available as standard. RKB production range also includes inch size cylindrical roller thrust bearings, engineered up to 50 inches outside diameter in conformance with RBEC accuracy specifications. Executions requiring antirotation devices on the plates, lifting holes and integral radial roller bearings are also available. There are standard design variations of RKB inch series thrust bearings. Each design is based on a standard single acting with addition of special components to modify its function: the AT aligning type with sphered housing plate for a possible initial static misalignment up to 3°; the crane hook thrust type with the weather shed pressed on the rotating plate; the DT double acting thrust bearing and the DAT aligning style combination of DT and AT types; the SDT simplified double acting thrust with only one roller assembly and two thrust plates.
