We have four 56mm BB trannies running our mecanum drive. The 8" AM mecanums are directly mounted to the BB drive shaft which is supported on the outboard end quite securely. (photos at
http://www.chiefdelphi.com/forums/sh...highlight=1346 )We "broke in" the gearboxes for at least 30 minutes of continuous operation before installing them.
We have been running our robot for... well... less than 30 minutes and noticed one or two of the trannies were beginning to show significant backlash.
We took the transmission apart and noticed that while the final drive plate had not failed completly it was very close to failure as discussed in this thread.
This is after very low use with ONE CIM in a relatively low dynamic loading (no chain to snap) environment.
We have noticed that the two BB's that came in the KOP have less backlash. They also fit much more nicely onto the CIMs than the two we bought in early January. Perhaps there is variation from batch to batch to deal with as well.
In any case, here is one more report of BB 56mm failing (or at least coming close enough to failure to count) under ONE CIM load... and at extremely low cycles, too.
We are also pondering solutions, but it seems manufacturing a new plate, or having one manufactured is what we are going to have to do if we want to use these trannies.
Jason