Our team is looking to move to a WCD drivebase next year (after 5 years of using the KoP drivebase) and plan to prototype one in the offseason.
[LIST]5mm HTD belt drive using 30T pulleys. Back run is on inside of chassis, front run is inside tube.
2.5" x 1.5" x .125" side rails. Fits 30T pulleys with a 1/16" raise for front/back wheels and 1/16" drop for center wheels.
Vex 3CIM Ballshifter attached with through bolts and in-tube nylon spacers
4" Vex Traction Wheels
Welded chassis design, though may use 221’s Chassis Tube Connectors as well (don’t know the pitfalls of a welded chassis yet)
Direct C-C belt run with .002" center add
[*]Riveted bellypan, possibly Delrin
We have liked the KoP drivebase but want to move to something a little more flexible. We are used to bullet proof drivetrains though (thanks AM!), so I wanted to make this as maintenance free and robust as possible.
I wanted to stick with belts for lack of maintenance, but was worried about the large cantilever that running two 15mm belts inside the chassis would require. So I ended up running one inside the chassis, and one inside the tube and out of the way.
This thread, and others, led me to go for 15mm if I wanted to be bulletproof.
I considered VersaBlocks, but I didn’t like the need for the cam when I never intend to adjust tension. VBs without the cam means relying solely on friction to hold them in place, which doesn’t fit the bulletproof requirement; so it was press-fit bearings into the tube.
Now for some questions:
[LIST]How safe is it to run bearings in 1/8" tube wall in heavy defense games? I have seen problems with 1/16th" wall, but I’m not sure about 1/8"?
Will my bumper mounts be sturdy enough if welded? I have seen a lot of designs that have a top bar connecting each mount, though I don’t know how much resilience that adds.
Are nylon spacers inside the tube appropriate for attaching the gearbox to the rails? Would just having the bolts run through the inner tubing wall work better?
Is 2 thou center add reasonable for a drivetrain? I have heard of people going without a center add, but I’m used to preloading.
[*]How big should washers be on the end of my shaft to hold the wheels on? I am thinking mine are a little undersized.
Any other comments or suggestions are definitely welcome! I would like to get some solid feedback before we start machining.
CAD available here
Also, my second link is messed up Here are the other pictures.