The rollers in a single row cylindrical roller bearing (fig) are always guided between the integral "open" flanges on one of the rings. These "open" flanges combined with the specially designed and surface treated roller ends, provide improved lubrication, reduced friction and consequently lower operating temperature.

The ring with the integral flanges together with the cylindrical roller and cage assembly can be separated from the other ring. This results in easy mounting and dismounting, particularly where the load conditions are such that interference fits are required for both rings.

SKF single row cylindrical roller bearings can accommodate heavy radial loads and high speeds. They are manufactured in several different designs, the main difference being in the configuration of the flanges. The most popular are the NU, N, NJ and NUP designs.

NU design
The outer ring of bearings of the NU design (fig) has two integral flanges and the inner ring is without flanges. Axial displacement of the shaft with respect to the housing can be accommodated in both directions within the bearing itself. The bearings are therefore used as non-locating bearings. For manufacturing and maintenance reasons, the two outer ring flanges of large-size bearings of the NU design which are identified by a Drawing No. may not be integral but take the form of loose flange rings.

N design
The inner ring has two integral flanges and the outer ring is without flanges (fig). Axial displacement of the shaft with respect to the housing can be accommodated in both directions within the bearing itself. The bearings are therefore used as non-locating bearings.

NJ design
The outer ring has two integral flanges and the inner ring one integral flange (fig). The bearings are therefore suitable for the axial location of a shaft in one direction, see also under "Dynamic axial load carrying capacity".

NUP design
The outer ring has two integral flanges and the inner ring one integral flange and one non-integral flange in the form of a loose flange ring (fig). The bearings can be used as locating bearings, i.e. they can provide axial location for a shaft in both directions, see also under "Dynamic axial load carrying capacity".