A 2400ton crawler crane, owned by the Dutch firm Huisman-Itrec and built in 1966, is able to turn 360 degrees on its bogie wheels which run on a track. Each wheel was originally fitted with two conventional roller bearings mounted as non-locating bearings. However, when the crane turned, the outer rings of each bearing were subjected to continuous, but small axial movements in their respective housing, which over time, began to cause fretting corrosion.
Further problems originating from the initial design were that the bearings became locked in their housings which, in turn, induced higher thrust loadings and led to premature bearing failure.
The replacement of the roller bearings with SKF’s CARB toroidal roller bearing, with its low, broad roller profile, is the first of its type able to accommodate both angular misalignment and axial displacement in a single bearing, even when subjected to high radial loads, this makes it ideal for this application, and eliminated the fretting corrosion problem.
Axial movements, such as those encountered by the crawler crane, are taken inside the CARB bearing while still maintaining very low friction and negligible thrust loads.