Dynamic Load Calculation on Radial Bearing.

[TSK1972]

I am trying to to Dynamic load cals on deep groove radial bearings. the set-up consists of 4 piston/cylinders hooked up to motor and gear box. Using a crank, two piston are moved to one direction and the two on the other side are moved in the opposite direction. We ran the system at 1500 psi today and two of the bearings failed on one side. how do a do a load calculation and bearing life calc on this?

Thanks in advance.
TSK

 

[MikeHalloran]

If you've got paired bearings that are not specially selected to run with each other, they are pretty much guaranteed to fail prematurely.

Beyond that, I still haven't figured out what your geometry is, or why you can't get an estimated load from the kinematics of the system.



Mike Halloran
Pembroke Pines, FL, USA

 

[TSK1972]

I am working as a mechanical design engineer but I don't remember doing these calcs. The dual output shafts from the gear box are in the middle of the assembly with two piston/cylinders on each side. The pressure in the cylinders should be 2200 psi but we ran them at 1500 psi. This setup is used to cycle some diaphragms in a test set-up. We want to be able to cycle 4 diaphragms at a time therefore we used two output shafts from the gear box. How much load are the bearings going to see if the load is shared is between two bearing on each crank assembly.

 

[rob768]

Before you check loads, have you performed a failure analysis? Perhaps that gives you a better indication on what to look for. Maybe load isn't your problem, but maintaining a proper oil.

 

[sms]

Your best bet is probably to put load cells into your setup so you can directly measure the forces. How big are the pistons? The force from each piston is pressure times area. Sound like you are putting lot of force on the system to me. Assuming the piston is 2 square inches in area, then each piston is applying 3000 lbs, times 4 would be 12000 lbs of force. You didn't say how big the bearings are or what their load rating is, but if the are say 2 inch ID bearings, that may well be enough to fail them....

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