Knowledge and experience are of particular importance where four-row cylindrical roller bearings are concerned. The individual components must be mounted in the correct order. Parts which belong together are marked with letters (fig 1). In addition, all components of the bearing are marked with the same serial number, so that there is no risk of mixing components if several bearings are to be mounted at the same time. However, the inner rings and inner ring pairs are fully interchangeable and need not have the same serial number as the outer ring(s).
In the majority of applications the load is of constant direction, so that only approximately a quarter of the outer ring is under load. For this reason, the side faces of the outer rings are divided into four zones indicated by I to IV. The markings for load zone I are also joined by a line across the outside surface of the outer rings.
When the bearing is mounted for the first time it is usual to position zone I in the direction of action of the load. Depending on the operating conditions, the outer rings should be turned through 90° after a period of service so that a new zone comes under load. The recommended period is approximately 1 000 operating hours and the bearings should be inspected. The turning should take place at a suitable roll change.
If skilled personnel is not available to mount the bearings it is advisable, particularly where large bearings are concerned, to request the assistance of SKF service personnel. Further details of the SKF mounting service will be supplied on request.
Detailed mounting instructions are also supplied with all bearings.