More top tight radial method used in radial load bearing tapered hole, the typical example is the double row precision cylindrical roller bearings, using nuts to adjust the tapered journal bearing relative to the axial position, so that within circle have the right volume by radial expansion of the negative clearance, the method for machine tool spindle and multi-jet engine.
Axial preload law tightening and positioning in general can be divided into two constant pressure preload. Pretension in the positioning, you can by adjusting the size of bushes or gasket, get the right amount of preload; can start by measuring or controlling friction torque to get the right preload adjustment; can directly use the pre-adjusted the amount of preload duplex bearing pairs to achieve the purpose of pretension, this time without the user re-adjustment of the general, in short, all through the axial preload of ntn bearings, use the relative position will certainly not change. Constant pressure preload is to use helical springs, disc springs, etc. to get the right bearing preload method.
Preload spring rigidity - as less rigid than the ntn bearing, so constant pressure preload the bearings relative position will change in use, but the amount was roughly unchanged preload.
Location pretension pretension comparison with the constant pressure:
(1) the amount equal to the pretension, the position pretension to increase the effectiveness of the larger bearing stiffness and rigidity changes when positioning pretension load of bearings ntn much less.
(2) Position Preload in use, due to ntn bearing shaft and the temperature difference caused by the axial length difference, the temperature difference between inside and outside the ring due to the amount of radial expansion and displacement caused by the load effect would pre- compact volume changes; and constant pressure preload in use, changes in preload can be ignored.