NSK has developed a new series of tapered roller bearings for use in heavy-duty construction machinery (Fig.). The key feature of these bearings is the effective protection against creep between the inner ring and axle. The positive consequence: wear to the axles of the machines and to the bearings is significantly reduced.
When conventional tapered roller bearings are used in the wheels and axles of dumper trucks and other mine vehicles, slip between the surface of the inner ring and the axle is frequently observed, which can lead to premature wear of the axle and/or the bearing bore. This results in machine failure and costly repairs. Tried and tested countermeasures already exist to prevent or at least minimise creep. But these protective measures have not proven sufficiently effective against the high loads to which heavy construction machines are exposed.
NSK has studied this phenomenon intensively and carefully analysed the processes that lead to slip on the inner ring. The main cause is a local deformation of the inner ring under very high loads. On the basis of these analyses and the extensive material know-how that is part of the core expertise at NSK, a new solution has been developed. The design features include a more stable inner ring. A higher number of rollers ensures better load distribution. The new bearings provide around eight times better protection against the slip described and the resulting wear. This improvement is very noticeable for the manufacturer and the end-user of the construction machinery, because unscheduled downtime is reduced and maintenance costs lowered.
One of the advantages of the new solution is that the improved tapered roller bearing only requires a change to the specification and not at the connection of the bearing and axle. Moreover for these bearings NSK uses a special heat treatment process to increase resistance to surface fatigue on both the inner and outer ring. This measure also lengthens the service lifetime of the roller bearing.