When mounting double row tapered roller bearings the individual bearing components must be mounted in the correct order. The components are identified by a letter (fig 1). All the components of one 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.
In the majority of applications in rolling mills, the direction of load is constant on the outer ring, so that only approximately one quarter of the outer ring raceways is under load. For this reason, the side faces of the outer rings are divided into four zones (fig 2) marked with I to IV. The marks for zone I are additionally joined by a line across the outside surface of the outer ring.
When mounting for the first time it is usual to position zone I in the direction of action of the load. When the chocks are remounted, the outer rings should be turned through 90° so that the next zone is exposed to the load. Detailed mounting instructions will be supplied with the bearing if required.
When mounting smaller TDI-configuration bearings care should be taken to see that the intermediate rings, which are often relatively thin-walled, are not deformed (compressed), for example, when tightening the cover screws. This would lead to too small an axial clearance in the bearing or too high a preload. It is, therefore, recommended that these bearings be fitted into their housing seats, e.g. by providing a spigot in the cover which is appropriate to the bearing width.
If sufficiently experienced personnel is not available for mounting the bearings, it is advisable, particularly if they are large bearings, to contact SKF. SKF service personnel will then quickly and reliably perform the mounting on site.