pic: Cim with Encoder CUI Inc. AMT 102-V3524

[asid61]

Originally Posted by Richard Wallace

Sorry I misunderstood your idea earlier.

So, if I am getting it correctly now, you would put a third bearing on the motor shaft, between the encoder and the pinion? Maybe a 608, with 8mm ID x 22mm OD x 7mm length. Then you'll have 31 - 9 - 7 = 15 mm left for the pinion and its retainer, so a standard 19 mm pinion would need to be cut down to about 12 mm. This will still be enough to engage a 3/8 inch (9.5 mm) gear tooth face. A little more demanding of axial gear alignment, with very tight axial clearances.

Edit: maybe leave about half of the 608's axial length protruding from the encoder adapter so it functions as a pilot for the gearbox? This would allow larger pinions (e.g., 14 tooth) to clear the pilot diameter, making gearbox assembly easier, while relieving some of the tight axial clearance problem.

Am I wrong in saying that the axial tolerances can be a little looser, as the whole cim/encoder assmbly is mounted by two screws with no boss? I'm not sure if that would work, but wouldn't the cim shaft be aligning this anyway?

I would actually use an 8mm ID x 16mm OD 5mm long bearing. On a 3/16" thick plate, it only sticks out about a hundreth of an inch. It has a pretty high load rating too.