ball bearing in assemblies

[aeman]

hye,
i need to do some stress analysis on suspension arm assemblies which include the use of ball bearing..my problem is, there are some errors regarding with the constraint around the ball bearing area..anyone know what type of constraint that need to be used and where to apply it...thanx~

 

[KurtStark]

We used a spring with different spring rates in different directions as replacment for a linear guide. This works pretty good. I assume it would do the job also on rotary bearings, probably with using a cylidrical coordination system.
The difficulty is to find out the spring rate for the bearing (in real world not linear).

 

[aeman]

sorry,but i'm still don't get the right idea yet. Can u elaborate more on the cyldrical coordination system?

 

[KurtStark]

Sorry aeman, I missed your question above.


I tried it and found that the spring properties can not be defined in a cylindrical coordinate system, but z as rotation axis you can define Kxx=Kyy, Kzz, Txx=Tyy and Tzz=0 (or Tzz<<Txx for simulating some friction). With this the bearing can have free rotation and shows the stifness in the other directions.
As mentioned above the difficulty is to get the spring rates in the various degrees of freedom, in reality they are not linear. For the linear rails we did evaluate them by experiment with the load we have in our application.


Good luck!

 

[moriarty]

The bearing manufacturer should be able to provide the
stiffness.

Not sure you need all this for just suspension analysis
though ...

 

[santu.prasa]

please once try to use the tangent relation.......