Ball Bearing Stiffness (horizontal and vertical)

[pz7q]

As you may know, there are equations for ball bearing stiffness calculations in radial and axial directions. The radial direction is actually the load direction.

Does anybody know (or anywhere to look for) the ball bearing stiffness calculation for horizontal direction, i.e. perpendicular to both load direction and axial directions?

Thanks.

 

[vanstoja]

Because of the geometric symmetry of ball bearings, I would expect the quadrature stiffness (perpendicular to load and axial directions) to be about the same as the load direction stiffness. The maximum difference should be equal to the loading in the load direction and may be influenced by the number of balls employed since the quadrature axis may have a full or only partial ball through the axis. For fluid film bearings where the shaft is displaced non-radially by the loading, fluid film stiffnesses in load and quadrature directions can be substantially different.

 

[Philrock]

It will depend very heavily on the magnitude of the load, the rating of the bearing, and most importantly, the internal clearance built into the bearing. A typical ball bearing does have internal clearance built in. As such, I would expect that stiffness for small radial loads perpendicular to the main radial load would be extremely low - the disturbing force would just move the shaft so the clearance is in a different angular location. If you need quantitive information, I suggest you do your own experiments.

 

[diamondjim]

You might want to check out Tedric Harris
"Rolling Bearing Analysis", Chapter 9.
Lots of luck. It would be easier to have
the bearing manufacturer do this for you
and you could do it yourself to confirm
the procedure.