High-precision applications generally call for bearings with a low cross-sectional height due to limited space and high requirements for rigidity and running accuracy. Bearings with a low cross-sectional height are able to accommodate relatively large-diameter shafts to provide the necessary rigidity within a relatively small bearing envelope.
Angular contact ball bearings, cylindrical roller bearings and angular contact thrust ball bearings commonly used in machine tool applications are almost exclusively bearings in the ISO 9 and 0 diameter series (fig. 1).
Angular contact ball bearings in the 2 diameter series are rarely used in new designs, but are still common in existing applications. When a compact cross section is a key requirement, angular contact ball bearings in the 8 diameter series are the preferred solution.
By selecting bearings in the 9 or 0 diameter series, it is possible to achieve an optimal bearing arrangement regarding rigidity and load carrying capacity for a particular application within the same radial space.
Angular contact thrust ball bearings for screw drives have larger cross-sectional heights. Diameter series 2 or 3 is common for these bearings. The available space is typically not a major concern, but load carrying capacity is extremely important.