Usually, the shaft is supported by two bearings in the radial and axial directions. The bearing on one side is called the fixed end bearing. It bears two kinds of radial and axial loads and ACTS as the relative axial displacement between the fixed shaft and the bearing box.The other side is called the free end, which only bears the radial load and can be moved relative to the axial direction.
The fixed end bearings must be fixed to both the shaft and the bearing box. The most suitable bearings are radial bearings that can bear the combined load, for example, deep groove ball bearings, centering roller bearings and double-row or diagonal contact ball bearings or tapered roller bearings.A combination of radial bearings bearing a simple radial load, such as cylindrical roller bearings with no retaining edge on the inner and outer rings, combined with deep groove ball bearings or four-point contact ball bearings or two-way thrust bearings, can also be used as fixed end bearings.At this point, the second bearing provides bidirectional axial positioning, but must be installed at a radial distance from the bearing box.When the length of the free end bearing changes due to thermal expansion of the shaft, no extrusion will occur in the bearing.Axial displacement can occur in the bearing interior, bearing ring and bearing seat.
"Cross fixing" means a bearing arrangement in which each bearing is positioned one way to the shaft and in the opposite direction.This combination is mainly used for short axes.All radial bearings that can withstand axial load in at least one direction are applicable, including deep groove and angular contact ball bearings, tapered roller bearings, and NJ cylindrical roller bearings. When angular contact ball bearings or tapered roller bearings are used, preload must be applied in some cases.Selection of bearing configuration