SKF make the earth move for Volvo

Engineers at Volvo have selected SKF’s CARB toroidal roller bearings for the steering mechanisms of their articulated dumptrucks.

On the A35 dumptruck, the two hydraulic cylinders within the steering mechanism are fitted with low-profile, sealed-for-life CARB bearings (type C6912-2NSV). The cylinders, one mounted on either side of a central pivot joint, swing the front tractor unit and separate the rear trailer about the pivot by synchronized extension and retraction.

The bearings are subjected to high shock loads in conjunction with small oscillating movements and deflections. Traditionally, the hydraulic cylinders would have been fitted with plain bushings which are prone to damage under these conditions and, because they rely on a large sliding bearing surface, are difficult to lubricate for long-lasting protection.

CARB bearings overcome these problems by using a large number of long, small-diameter rollers that are surrounded by high-quality grease. The rollers only need to rotate through a very small angle for the load-carrying contact to be made between the lubricated surfaces. Before fitting, Volvo subjected the CARB bearings to extensive and rigorous testing, both in the laboratory and in long-term field-service trials.