Flipped 4x 775 Pro WCD Gearbox

My team is looking to switch to a different gearbox setup compared to our DeCIMate and WCP SS setup from last year due to some issues we had throughout the season. I designed this gearbox around using the same mounting style as the WCP SS to allow us to swap this in with some of the current drive-trains we have fabricated already. I do know that the motors are currently intersecting :mad: By the time I realized it, it was already basically midnight so I decided why not post it and just shift things like .125" before we machine the plates. There are also things such as snap rings and a spacer in a couple locations missing.
But besides the motors intersecting…
Is the pocketing too aggressive?
does the gearbox need more cross supports? The way I designed the gearbox I didn’t allow for a lot of support between the plates besides the two standoffs and the 2 shafts.





CAD Folder: https://drive.google.com/drive/folders/1lBPIsL_5ODtEzYFeiGKUUUNyTgFZ25P9?usp=sharing

I like it! To answer your questions, the lightening doesn’t look too agressive to me. In fact, there are some little corners in the small plate that probably don’t need to be there. I would definitely consider adding more standoffs, but I agree it’s not easy to find room for them - maybe in the corners between motors. I worry about driving a WCD with those little pulleys. Have you done that before successfully? You know you’ll have to take the gearbox apart if you need to change the belts right?

Yeah, seconded on the pulley size and standoff advice. The pulley size ultimately depends on the size of the wheel you are using. The rule of thumb is to use 15mm belts with 8*diameter of the wheel, or the largest one you can package or buy. (In 2018 we had 6" wheels with 42T pulleys and didn’t have any trouble) So if you are using 3.5-inch Colsons, shoot for about 30 tooth pulleys for large safety margin. This gets tricky when you’re driving larger, 6" or 8" wheels…
Edit: Here’s a thread on belt load ratings (https://www.chiefdelphi.com/forums/showthread.php?t=159798&highlight=belt)

I was looking at the pictures more and noticed all the empty space on the output shaft in the gearbox. Why not reduce the size of the spacers and take up that space? It would move the motors over the drive rail, but take up less bellypan space. If you don’t want the drive rails covered, then that makes sense, just thought I would throw that out there.

We have never done belts for a drivetrain so we were looking to attempt that this year during the off season. We may just stick with chain like we have in the past and experiment with 25 chain to save some weight and space. It appears I’ll have to shift my motors up to fit a larger pulley.

I attempted to have them hang over a little bit but I noticed they would run into the 2x1 rail at the current motor positions. I may try to add larger gears to get the spread. Ideally I would love to keep this a 2 stage gear to save some weight but if things just dont line up like planner, it may not happen. I also could have gone maybe .25" short we with the standoffs but I wanted to have a little space between the gearbox plate and motors. Last year we regretted not swapping motors between state and worlds, so we are hoping a setup like this will be easier to access the motors and pull them without having to tear apart everything.