Cylindrical roller bearings cope with axial loads
Cylindrical roller bearings have traditionally had only a limited capacity for axial loads. But engineers at Schaeffler claim to have overcome this limitation by optimising the bearings’ contact geometry and by using new calculation methods and modified manufacturing processes.
In the past, the axial/radial load ratio in such bearings could not be higher than 0.4, which meant that the axial load could not exceed 40% of the radial load. In Schaeffler’s new X-life cylindrical roller bearings (shown above), this value has been increased to 60%, due to specially curved roller faces designed to optimise contact conditions between the roller faces and ribs.
This improved contact geometry allows a lubricant film with a much higher load-carrying capacity to form. During axial loading, the rollers slide on this film, reducing the risk of "mixed" friction and preventing wear of the ribs and roller faces.
The frictional moment under axial load is claimed to be up to 50% less than before. This means that the bearings operate at lower temperatures, and that the lubricant also stays cooler, resulting in the formation of the high load-capacity lubricant film. This ensures that the roller faces and bearing ribs stay optimally separated.
Schaeffler says that the new design will result in longer service lives for the bearings. It will also give rise to new design opportunities, such as downsizing, while the lower friction will save energy.
