Multi-row full complement cylindrical roller bearings are mainly used in small cold rolling mills where very considerable rolling forces occur but where rolling speed is limited. Other applications for these bearings include straightening machines, shears and extruders. To facilitate efficient lubrication, all multi-row full complement cylindrical roller bearings have lubrication holes, or an annular groove and lubrication holes in the outer ring.
SKF multi-row cylindrical roller bearings are mainly produced to the NNU design described below. To special order, SKF can also produce three to five-row bearings of the NNCL and NNC designs. However, because of the large number of possible designs and sizes NNCL and NNC design bearings are not shown in the product tables. Further information on these bearings will be sent on request.
NNU design
The bearings have two loose flange rings on the outer ring, a
flangeless inner ring and four rows of rollers or eight rows of
rollers. The bearings are separable and enable a certain amount of
axial displacement of the shaft relative to the housing in both
directions to take place within the bearing.
NNCL design
These bearings have four to six integral flanges on the inner ring
and a flangeless outer ring. Retaining rings at both sides of the
outer ring raceway serve to hold the bearing together. A certain
amount of axial displacement of the shaft relative to the housing
can take place in both directions inside the bearing.
NNC design
These bearings have four to six integral flanges on the inner ring
and one integral flange ring and a loose flange ring on the outer
ring attached to the outer ring which holds the bearing together.
These bearings are able to axially locate a shaft in both
directions.