Allowable bearing forces due to unbalance

[geesamand]

My company designs gear reducers with attachments. The balance quality of the attachments follows our company standards but it's a very basic practice. These are rigid rotors operating safely below first critical speed.

Balance quality can be calculated from the allowable bearing forces. How might I determine my allowable bearing forces? I can think of a few options but I'd love to know if there are good rules of thumb or other design practices to consider.

Thanks, David

 

[Tmoose]

Direct coupled ? Belt drive?
Rolling element bearings or some flavor of journal bearings?

What is the nature and function of these "attachments?" Are they heavy, or cantilevered, or is their function to make aggressive interrupted cuts in slabs of oak or to claw deep trenches in the earth ?

I think the reaction forces from the gearing are likely to be much higher than "centrifugal force" from an "attachment" balanced per ISO 1940/1 G 6.3 which is a general machinery balance tolerance.
If the bearings are as rugged as I'm AssUmINg, the unbalance that will create a force equal to 10% of the bearing capacity may well cause noticeable and unacceptable amounts of 1X vibration in operation.

I'm thinking API or AGMA has much to say about gearbox component balancing, but masybe not "attachements."