Quote:
Originally Posted by Joe G.
Good start!
What was the rationale for the split plate structure? As drawn, you don't really gain any practical strength from the outer plates, since they do not constrain the shafts in any way, or reinforce the parts of the inner plates which will see stress. Tolerance stackup between the inner and outer plate may also cause you issues with gear mesh at the miniCIM pinion, depending on how it is done. The only thing I can see that the outer plates are doing for you is standing off the miniCIM so that it doesn't interfere with the 1st stage shaft's bearing, but this could be achieved through either a thicker plate or a standoff plate slipped in front of the miniCIM.
There's a lot of material up top that isn't really serving any purpose. This can be narrowed up a lot to save some weight. A cool trick which could come in handy here is to run the motor mount bolts all the way through both plates, with spacers serving as your upper standoffs.
It will probably be fine as is, but it's generally considered good practice with this kind of lightening to put a band which runs all the way around the outer edge of the miniCIM, so that it has a solid surface to react against to prevent bowing.
You're missing a few fillets in your lightening, which will cause problems in manufacturing if this is made with a mill, and will generate stress concentrations where you least want them no matter what.
How do you plan to retain the output shaft?
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Thanks for all the advice. The reason I have two 1/8" plates is because we currently only have access to a laser cutter and a mill, and the laser cutter cant cut more than 1/8" thick aluminum. Originally, the plates were 1/4" thick, but since we don't have access to a CNC mill, I had to resort to 1/8". I do plan to add bearings to the outer plates. Also, correct me of I'm wrong, but wouldn't adding more standoffs at critical points between the inner and outer plates increase rigidity? I'm aware of the faulty fillets and will fix. I'll also add a ring to support the CIM, thanks for bringing it up. Didn't think that gear meshing would be a problem, but I can see it now. Would mounting the cim to the inner plate instead be a solution?
And regarding the extra material at the top, I've left it there for now since I don't have a clue how its going to be mounted.
Again, much thanks for all the advice, this is my first year so I'm not too experienced. When I get the time I'll go ahaid and update the model.