Cageless, full-complement cylindrical roller bearings have the maximum possible number of rollers and can sustain much heavier loads than cylindrical roller bearings of the same size with cages. On the other hand, their high-speed capability is inferior to bearings with cages.
It is possible to use a smaller and lighter bearing without a cage while retaining the loading capacity and the service life.
These high-capacity bearings are produced in open and sealing designs. Sealing full-complement double row cylindrical roller bearings are often used in construction machines, mainly in crane sheaves. These bearings have an optimised internal design for low speed and high load. The bearings are lubricated and have a lubrication groove and hole. They are also produced with anticorrosive surface treatment for demanding environments.
Three different versions of open bearings:
NNCF – These bearings are a double-row version of the NCF bearings. They have three ribs on the inner ring and one rib on the outer ring. They have a retaining snap ring in the outer ring at the side opposite the outer ring rib. The retaining snap ring should not be axially loaded during operation.
RS-48E4, RS-49E4 – Double-row outer ring with centre rib, two single-row inner rings with ribs. The outer and inner rings and rollers are not separable since there are two retaining snap rings at the sides of the outer ring. They can sustain an axial load in either direction so they can be used as fixed-end bearings.
RSF-48E4, RSF-49E4 – Double-row outer ring without ribs, double-row inner ring with three ribs. The outer and inner rings and rollers are not separable since there is a retaining snap ring at the middle of the outer ring. They can be used as free-end bearings. An oil groove and holes are provided at the centre of the outer ring.
Shielded bearings
RS-50 – Double-row outer ring with centre rib, two inner rings with ribs. Both sides shielded by contact seals and are pre-lubricated, but it is possible to replenish the grease through an oil groove and holes in parts mating with the inner ring. They can sustain high loads and are suitable for demanding environments as they are surface treated for rust prevention. Mainly used for construction machines.
Bearing series: NNCF, RS-48E4, RS-49E4, RSF- 48E4, RSF-49E4, RS-50, RS-50NR (NSK), NAS 50.. (IKO)
More details in the catalogues: