Multi-row cylindrical roller bearings
Four-row (fig 1) and six-row cylindrical roller bearings (fig 2) are used almost exclusively for the roll necks of rolling mill stands, calenders and roller presses. Their friction is low compared with other roller bearings. As they are normally mounted with an interference fit on the roll neck, they are particularly suitable for rolling mill applications where the rolling speed is high.
The low bearing cross section allows for relatively large roll neck diameters in comparison with the roll diameter. Since very many rollers can be incorporated, the radial load carrying capacity is exceptionally high.
Multi-row cylindrical roller bearings are only able to accommodate radial loads. They are therefore mounted together with deep groove or angular contact ball bearings, or with tapered roller bearings, either radial or thrust designs, which take up the axial loads.
The four-row and six-row cylindrical roller bearings are of separable design, i.e. the ring or rings with integral flanges and the roller and cage assemblies can be mounted independently of the free rings, or all bearing components can be mounted separately. This considerably simplifies bearing mounting, maintenance and inspection. A certain limited axial displacement of the shaft with respect to the housing can be accommodated within the bearing.
SKF four-row cylindrical roller bearings have a cylindrical bore and some sizes are also available with tapered bore. Bearings with tapered bore can be adjusted during mounting to give a certain radial internal clearance or a defined preload.