pic: Inverted CIM 2-Speed Gearbox

[KohKohPuffs]

Originally Posted by Chris is me

Once your wheels slip under load, gearing any slower doesn't do anything to increase your pushing force, it just decreases your power consumption. You're traction-limited rather than torque-limited.

For a 150 lb robot with roughtop tread, that "magic number" is around 6 feet per second, depending on your efficiency, exact weight, wheel design, etc.

I've been punching some numbers into JVN design calculator, and I managed 16.85fps high, and 6.76fps low.

This will be a new design (but I'm keeping the inverted CIMs), since to do this I had to have the dog gears be the driven gears rather than the driving gears in the second stage (shifting on upper shaft). Also, in order to have the gear space in the gearbox, I'm most likely going to keep the idlers:

1. The idler gears are easily replacable in case they wear out
2. Using my logic, the idler gears are made of steel, so I doubt wearing down is going to be significant

As for a belted gearbox, I think our team wants to move away from belts. It's a bit complicated, but even if it is better than idlers, I'd rather work on the current style I have going.

Thoughts?