The selection of bearing collocation

Normally,the shaft is supported by two bearings in radial and axial directions.Then,one of the bearings is called the fixing-end bearing which carries the load in radial and axial directions.It controls the comparative axial movement between the shaft and the bearing.The other one is called the free-end bearing that only carries the radial load and the bearing can comparatively move in the axial direction in order to solve the problems of expansion of the shaft caused by changes in temperature and the clearance error in mounting.

For the fixing-end bearing,it must be chosen from which the axial movement can be prevented.For the free-end bearing,it must be chosen to use its sliding surface to make axial movement(such as cylindrical roller bearings) or use its mounting surface to move(such as radial ball bearings).On the comparatively short shaft,if there are no differences between the two bearings,the bearings that only move in the fixed single axial direction(such as radial thrust ball bearings) are prferable.