Oooh, CAD! Shiny! If criticism is welcome, then I offer up the following. I ensure you that my intentions are not to denigrate your design, but instead to offer some criticism. PM me if anything here doesn’t make sense, I’d love to explain it to you over PM, without the pressure of an open channel.
First off: Cheeseholing your drive frame. Why? The weight saving there is minimal, and the time it would take to machine those parts could be better spent doing something with more impact, such as more time in design to make sure your robot will reach maximum effectiveness during competition. Instead of spending time hobbing the structure of your robot away for those precious few pounds, I suggest spending the time doing some FEA on your chassis to make sure it can withstand the forces of the game, while still using the minimal materials possible. I’m sure you can chop the weight down without needing to spend an enormous amount of time machining key structural components.
Second: Gearbox mounting. It makes me nervous having only two bolts holding something that critical to an already weakened member. If you move the gearbox down, so more of the sideplate face is flush against the chassis member. This allows the bolts to take less of the load when the gearbox is under stress.
Third: Gearbox sideplates. Yes, milling out enormous pockets on the gearbox plates look cool. Yes, it provides bragging points to other teams. Is it necessary? Not if the design is done well enough. If your goal is to lose weight, look at designing your side plates around a different material. I highly recommend Delrin or UHMW. You will (most likely) save machining time as well as cost and weight.
Fourth: Gears. Aluminum gears, unless they’re pre-fabricated, are not worth the work. Your team MIGHT save some weight by going with this option, but is the insane cost and manufacturing time worth the weight? Instead of going with exotic materials, it might be a better design decision to go with something strong and proven.
I might be designing a little to “conservatively,” but I’ve yet to have a gearbox failure by working with these principles. As a great mentor taught my old team, the most important question is not what can we build with this, but Why are we building this with that?
I really like the design you have going for the chassis, assuming you make a few tweaks. You’ve got a cool and innovative “crumple point” in the form of those rounded bumper plates. You’re also going to get a lot of strength out of the triangles you’ve created in the frame. However, you might gain even more if you design in a chassis member across the front of the frame, and tweak the superstructure to suit.
Good work on the CAD, it’s a valuable skill. Never stop designing things!
