1 radial preload method

More top tight radial method used in the radial bearing load of the tapered hole, the typical example is the double row cylindrical roller bearings precision, using nuts to the tapered journal bearings relative to the axial position, so that the inner circle have the right to get the radial expansion of the volume of negative clearance, this method is used for machine tool spindle and the jet engine.

2 Axial preload methods

Axial preload positioning method can be divided into constant pressure preload and preload

Preload in the positioning, you can adjust the size bushing or gasket, get the right amount of preload; can start by measuring the friction torque or control to get the right preload adjustment; can directly use the pre-adjusted amount of preload the pairs of double bearing preload to achieve the purpose, at this time generally did not require users to re-adjust, in short, all through the axial preload of the bearings, use the relative position certainly does not change. 

 Constant pressure preload is to use helical springs, disc springs, etc. to get the right bearing preload methods. The rigidity of the spring preload - as is much smaller than the rigidity of the bearing, so the constant pressure preloads the bearings relative position will change in use, buts roughly the same amount of preload.

Positioning preload and constant pressure preload are as follows:

(1) the amount equal to the preload, increased rigidity of the bearing preload positioning the effect of large changes in rigidity and positioning of the bearing preload when the impact load is much smaller.

(2) positioning preload in use, due to the shaft and bearing temperature difference caused by the axial length difference, the temperature difference between inside and outside the ring caused by the radial expansion and the amount of displacement caused by the load effect, will preload the amount of change; and constant pressure preload in use, changes in preload can be ignored.