Single-row cylindrical roller bearings are of separable construction. The ring with flanges is assembled with the cage and the rollers. During mounting, the rings are to be fixed on to their respective seats – Inner ring on the shaft and outer ring on to the housing and then they have to be put together carefully. Depending on the ring-roller-cage configuration either on the inner ring or the outer ring, the bearing series are designated as NU and N. Series NJ and NUP are variants of the NU design – denoting whether the separable inner ring has one flange (NJ) or one flange and truncated inner ring with a separable guide flange fixed on the other side of the flange so as to keep the width of the inner ring assembly same as that of the outer ring (NUP). They are manufactured in multiple series.
The bearings feature high rigidity, low friction, an ability to transmit high radial loads and are suitable for high rpm. N or NU series bearings should not be exposed to axial loads. Nj series bearings can carry limited axial load in only one direction, whereas NUP series series of bearings can carry limited axial loads in both the directions.
The bearings are supplied with standard clearance and normal accuracy. However, bearings with lower or higher radial clearances as well as higher running accuracy can also be supplied.
The bearings in the N design – the inner ring has two pilot flanges, the outer ring is without the pilot flanges. Axial displacement of the shaft towards the element (body) is possible in both directions.