What is the bearing pre-tightening? Rolling bearing pre-tightening purpose and method

What is the bearing pre-tightening? In most of the running state, the rolling bearing with the proper clearance to use. According to different purposes, but also in the installation of bearings, bearing produce internal stress in advance, so that the bearing under negative clearance is used, the use method called preloaded. Mostly such as the angular contact ball bearings and tapered roller bearings, used two opposed, bearing clearance is adjustable. If the pre-tightening force exceeds the limit, will lead to abnormal heat, friction torque increases, the fatigue life decreased, and so on. Therefore, to fully research condition, the purpose of the preloaded prestressing force to decide. Rolling bearing pre-tightening purpose, the main purpose of the preloaded and typical example is shown below: ( 1) In shaft radial and axial positioning at the same time, the inhibition of the shaft. Machine tool spindle bearing, measuring instrument bearing. ( 2) Improve the stiffness of bearings. Machine tool spindle bearings, automotive differential with bearings. ( 3) To prevent axial vibration and resonance caused by different sounds. Small motor bearings, etc. ( 4) Inhibition of spin roller sliding, revolution of sliding and rotation. High speed angular contact ball bearings, thrust ball bearings, etc. ( 5) Keep the roller ring relatively correct position. Thrust ball bearings, thrust spherical roller bearings, etc. , used in the horizontal axis. Rolling bearing pre-tightening methods: 1, positioning positioning preload preload is a guarantee to buy bearing in use without changing the axial prestressing method of relative position. The method is as follows: ( 1) In order to implement the preloaded width will be adjusted in advance or the combination of axial clearance bearing use after fastening. ( 2) Using the adjusted the size of the baffle, the filler piece on bearing pre-tightening ( See figure 1) 。 ( 3) The fastening of the axial clearance can be adjusted screw, nut. On this occasion, in order to get the right amount of preloaded, to start determination of friction torque and adjust the clearance. Example 2 figure 1 positioning preload constant pressure and constant pressure preload preload is a kind of use such as spiral spring, disc springs on bearing pre-tightening methods. Change in use even if the bearing relative position, can also be roughly unchanged (pretightening See figure 2) 。 Figure 2 for constant pressure preload