Combined cylindrical roller/tapered roller bearing
SKF Magnetic Bearings
Combined cylindrical roller/tapered roller bearings, also referred to as "Kombi" bearings (fig 1), have been developed by SKF. They comprise two single row cylindrical roller bearings and one double row tapered roller bearing, and support radial loads and axial loads separately. The outer cylindrical roller bearings have high load carrying capacity and are only subjected to radial loads. The cylindrical rollers are guided between two integral flanges on the inner ring, whilst the low flange on the inboard side of the outer ring serves to hold the bearing together until it is mounted. The tapered roller bearing with steep contact angle positioned between the two cylindrical roller bearings has two rows of rollers in a face-to-face arrangement and takes the axial load.
These "Kombi" bearings are employed as work roll bearings on four-high stands of both hot and cold rolling mills and of cold sheet rolling mills (fig 2). Increased demands with respect to the quality and accuracy of the rolled product as well as further developments in the production process for sheet steel involving the introduction of contra-bending and axial displacement of the rolls have meant that work roll bearing loads have been considerably increased. This means that the four-row tapered roller bearings normally used as work roll bearings can often not meet the requisite life demands because of the much heavier radial and axial loads applied.