may cause the rolling element and the raceway between the sliding destructive

In order to ensure Slewing bearing satisfactory performance , needle roller / angular contact ball bearings like all ball bearings and roller bearings , must always bear acting on the radial and axial certain minimum load , especially if they want to run at high speed or subjected to high accelerations or rapid changes in the load direction . Under these conditions , the rolling element and the inertia force of the retainer and lubricants friction bearing arrangement may play a deleterious effect on the rolling conditions , and may cause the rolling element and the raceway between the sliding destructive .
Increase in radial needle bearing backing bearings on the necessary minimum radial load can be estimated using the following formula :
Frm = 0.02 C
Angular contact ball bearings necessary minimum axial load can be calculated using the following formula :
Where
Cold start or lubricant viscosity is very high, even demanding loads. Bearing weight of the components together with external forces generally exceed the minimum necessary load. If this is not the case, you must give Needle roller / angular contact ball bearings impose additional radial and / or axial loads.