Over the corona-cation (specifically the last 3 days), I’ve had lots of time to do CAD, and I’ve used that time to hone my WCD skills in a variety of ways. I’ve created four drivetrains to various degrees of completion, documented below. None of these designs involve chain tensioners, a shortcoming I am aware of and would not include on a competition robot.
Firstly, I’ve created an 8WD drivetrain with 3.25" wheels, using a custom single-speed 2-NEO gearbox.
Secondly, a 10WD drivetrain with 4" Colson wheels and a different 2-NEO single-speed gearbox. This design is the most viable for a competition robot and resolves many of the issues I had with our competition robot from this year.
Then we enter the realm of complete impracticality: a 14WD drivetrain using 2" stealth wheels, including a 3-775pro custom single-speed gearbox. A brainpan is necessary as the chain runs go below the bottom of the 2x1 side rail. The wheels on the ends have just over 0.15" of ground clearance. On the plus side, the bumper rails can mount directly to the top of the end rails since the wheels do not clear the top of the 2x1.
Finally, created completely on a dare by a team member, Camber drive. This design uses the 775pro gearboxes from the Stealth drive, but uses 18 1.625" Colson wheels as the drive wheels, cambered inward at an approximately 45 degree angle from the vertical. I put very little effort into this (it was done entirely between the hours of 11pm and 1am last night) so it is the least complete, and it is the only one where I had to resort to saying “just weld it” because I couldn’t think of another solution to attach the side rails. This is also easily the boatiest-looking drivetrain I’ve ever made.
All STEP files are available via Google drive at the link below:
If anyone has questions I probably don’t have answers but I’m happy to try.