Apart from the term radial clearance, which refers to an uninstalled rolling bearing, the term operating clearance is also frequently used. An operating clearance can be determined when a bearing is mounted and has achieved the operating temperature. In this case, the radial clearance is generally smaller than in an unmounted bearing.
Interference fits between inner ring and shaft and/or between outer ring and housing lead to the reduction of the operating clearance. The interference causes the expansion of the inner ring and the contraction of the outer ring.
Temperature influences such as a heat supply through a shaft or the cooling of an outer ring also result in inner ring expansion and/or outer ring contraction.
In general, we recommend a radial clearance of CN and larger (see Fig. 3).
Smaller clearances than CN are suitable for special applications. In this case, please contact our LFD engineers.