Rotary bearings are machine elements that support rotating shafts accurately while providing low friction condition. In order to obtain stable bearing performances over prolonged duration, appropriate bearing fit design considerations are required to avoid any negative effects ([Chart 1]) that may arise from bearings' rotary operation.

[Chart 1] Designs for bearing fit and issues to be solved

Design examples of rotary bearing application.

An example used here is based on "Inner race rotation : Outer race retained" arrangement shown in [Fig.1].

Selection of bearing fits based on shaft diameter

Transition fit or interference fit is selected to ensure the shaft and the inner ring will always rotate together.

[Chart 2] Selection example of fits (case for radial bearings)

Selection of fits for bearing holder bores

Clearance fit should be chosen for ease of assembly while preventing any deformation of bearings' outer/inner races. In general, [Clearance fit] (H7) is used. In case of light loading applications (H8) can be used, or (G7) when large temperature variations are to be considered.

[Chart 3] Fit selection examples for bores (case for radial bearings)