RKB row taper roller bearings and matched paired sets
RKB taper roller bearings have the rolling elements under the form of frustum of cone. They roll on tapered surface which, if extended, converges towards a single point on the bearing axis. The rollers are guided tangentially by the cage and axially by the big rib of the inner ring, on which they have contact. As between rollers and raceways there is linear contact, they can take heavy radial loads. They can also take heavy axial or combined loads, depending on the contact angle caused by the tapered elements. The contact angle is the one of the outer raceway generatrix. The single row taper roller bearings are of separable design, which means the outer ring/cup and the inner ring/cone with rollers and cage assembly can be separately mounted. The two parts are interchangeable. RKB taper roller bearings are manufactured both in standardized (metric and inch sizes) and in nonstandardized constructive version. The metric single bearings have standardized dimensions as listed in ISO 355:1977 and those designated with prefix J conform to American AFBMA 19.1/1987. The inch size bearings conform to American AFBMA 19/1974. The taper roller bearings can carry only single direction axial loads. Under pure radial loads, an axial force is induced within the bearings so that they cannot be used singly and a second bearing is required. A correct operational clearance or preload has to be identified for the correct performance and reliability of the application. RKB taper roller bearings have pressed steel cage as standard. For large size and/or heavy engineering applications, the steel pin-type cage and case hardened carburizing alloy steels can be considered. RKB single row taper roller bearings can also be produced with a rib on the outer cup as a flange to be used when the housing cannot be manufactured with shoulder, but only with a passed through hole so that, in this case, axial location can be provided by the bearing cup.
When the load carrying capacity of a single row is inadequate or where the load has to be located in both directions, RKB produces the single row taper roller bearings as ready-to-mount matched pairs. The matched pairs, generally metric sized, in “O” back-to-back (designation DB) or “X” face-to-face (designation DF) arrangements, locate the shaft in both axial directions and the optimum axial play in the two bearings is adjusted and guaranteed after mounting. In case of taper roller bearings, clearance should be in radial direction, but it is measured and adjusted in axial direction. RKB paired matching sets are made to normal and CLN class tolerances as standard corresponding to ISO 492:1986. The tolerances of the total width of the pair are not standardized, but an international common specification is applied. The matched pairs of taper roller bearings incorporate pressed steel cages guided on rollers.