Spherical roller bearings have the advantage that they provide a much larger load capacity than ball bearings and can accommodate axial force. One of the features that makes an Extreme Bearing unit stand out is its ability to accommodate axial displacement. The bearing seats in the housings are sufficiently wide to allow axial displacement of the bearing and to accommodate for thermal expansion and contraction of the shaft due to high or low temperatures. Temperature variations are therefore not a problem.
Self-alignment in a traditional bearing versus an Extreme Bearing
Traditional ball bearing design subject to axial displacement.
The traditional bearing unit portrayed in the drawing contains ball-bearing inserts fitted with a spherical outer ring (marked in red). The idea is that the bearing is self-aligning. However, this is not always the case. What usually happens is that the force (F) holds the outer ring of the insert firmly in the housing, making it difficult or even impossible for the insert to adjust itself. If the bearings are subject to excessive axial loading, the forces generated penetrate through the bearing, causing damage to the balls, inner ring, ball race and even the housing. Ultimately, the insert has to be replaced, while the bearing housing is also damaged permanently in many cases.
An Extreme Bearing does not use an insert with a spherical outer ring, but instead has a flat outer ring with a concave raceway. The concave raceway in combination with the spherical rollers operate over a wide range of contact angles thus the rollers align themselves correctly with the shaft and assembly without causing undue stress on the rest of the bearing assembly.