In screen grading, the material is separated mechanically on screen plates. Rolling bearings in vibrating screens are stressed by high, mostly shock-type loads. Moreover, the bearings, while rotating about their own axis, perform a circular, elliptical or linear vibrating motion. This results in high radial accelerations which additionally stress the bearings, and especially the cages, considerably. The operating speeds are usually very high. As a result, the bearing temperatures are up to 20 to 30 degrees Kelvin higher than in normal applications. In addition, considerable misalignments between the bearing locations and considerable shaft deflections have to be accommodated.