Rolling bearing is usually keep some internal clearance and running

Rolling bearing is usually keep some internal clearance and running, however, in some cases want to provide a clear negative retain their internal stress this is called 'preload. A preloading is usually applied to the bearing during the installation process can adjust clearance, such as the angular contact ball bearings or spherical roller bearings. Usually, two bearing is face to face, face or back to back form double-sided combination pre-tightening force. 1. Rolling bearing is usually keep some internal clearance and running: the purpose of the preload applications and some typical applications preloaded bearing as follows: ( 1) Hold the bearing at the exact location of radial and axial to keep running shaft precision. （ 2) Increase the bearing stiffness of machine tool spindle, pinion shaft automotive final drive gear (such as 3) Reduce noise caused by axial vibration resonance (such as small motor 4) To prevent sliding between roller due to gyroscopic moment of raceway high speed or high acceleration application of angular contact ball bearings, thrust ball bearing, 5) Will remain in place and roller bearing, thrust ball bearing and spherical roller installed on the horizontal axis of thrust bearing 2. Rolling bearing is usually keep some internal clearance and running: preloading method 2 to implement preloading through axial fixed position location opposite bearing preloading imposed on them by preloading their position, once fixed, remains unchanged at runtime. In fact, the following three methods usually used to get position preloading. （ 1) The previously installed double bearing adjustment size and axial clearance. （ 2) By using the appropriate size of the gasket or gasket to obtain the required spacing and preloading. （ 3) Bolt or nut, is used to adjust the axial preloading. In this case, the starting torque load should be measured to verify the correct