RKB spherical roller bearings are self-aligning and consequently insensitive to the misalignment of the shaft relative to the housing and insensitive to shaft deflection or bending. The permissible value is up to 3.5° approximately depending on bearing series and size.
These bearings have two rows of rollers with sphered raceway in the outer ring and two inner ring raceways inclined at the proper angle to the bearing axis.
Used to operate in arduous conditions, leading in design, RKB spherical roller bearings can accommodate, in addition to high radial loads, axial loads acting in both directions.
The production range of RKB spherical roller bearings comprises open bearings, sealed bearings (suffix 2CZ1) and bearings for vibratory applications (suffix ROVS).
Besides, RKB offers spherical roller bearings customized for specific applications, as, for instance, bearings with split outer ring and wider outer ring for higher permissible misalignment (suffix WOR) or with increased width dimension and consequent larger rollers for milling applications (project designation SRB) or for the support of the rolls of cold rolling Pilger mills for tubes.
RKB program includes the spherical roller bearings with both cylindrical and tapered bore (1:12 or 1:30 depending on series). Tapered bore bearings can either be mounted on tapered shaft seats or with sleeve on cylindrical shafts.
Limiting load may result in lubrication problems, specially in the case of large bearings. So such bearings are provided with annular groove and lubrication holes in the outer and/or in the inner ring (suffix W33, W33X, W20, W26, etc.).
Depending on the bearing series, size and/or application, RKB spherical roller bearings are manufactured in different constructive internal design versions (e.g. CA, MB, MA, CC, etc.).
RKB small and medium size spherical roller bearings are usually fitted with pressed steel cage or one-piece machined brass cage where the bearings have a central guide rib on the inner ring and symmetrical rollers with large dimensions for increased carrying capacity.
The bearings of normal design, with a central fixed rib, are fitted with machined brass or steel cage guided on the rollers or on the inner ring or outer ring raceway.
The main dimensions are in accordance with ISO 15.
The radial clearance can be normal, larger than normal (suffix C3, C4 and C5) or smaller than normal (suffix C2), measured on unloaded bearing in accordance with ISO 5753.
RKB spherical roller bearings of all series and sizes are stress relieved. They undergo a special heat treatment so that they can be used up to an operating temperature of +150° C for long periods without inadmissible dimensional changes occurring.
Some of RKB spherical roller bearings are also manufactured in the sealed version with contact seal on both sides. The seals are reinforced with steel sheet and made of an oil and wear resistant rubber (as nitrile butadiene for universal usage – suffix 2CZ1 – or fluoro base – suffix 2CZ – to withstand operating temperature up to about +200° C).
In order to locate the spherical roller bearings with the tapered bore onto a cylindrical seating, the adapter (designation H) or withdrawal (designation AH) sleeves are the most commonly used components with large shafts with h9 and h10 tolerance. They are easy-to-mount on smooth or stepped shafts and require no additional location.
Adapter sleeves are supplied along with lock nut and locking device (washer or clip).
For large sized bearings, both adapter and withdrawal sleeves are provided with oil grooves and oil duct at the threaded side to enable the oil injection method to be used for easy mounting and dismounting (designation OH and AOH).
All ISO series (also the outmoded series, such as 202 and 203) are in RKB manufacturing program with both straight bore (no suffix) and tapered bore (suffix K).