pic: Team 192's 2016 Gearbox

[Mihir Juvvadi]

Originally Posted by asid61

Looks very compact! I have many questions:
1. Why the use of the cim-cim pulley? Would that cause the cim shaft to bend sooner?
2. How is your shifting cylinder so tiny/compact!?
3. What is the weight without cims?
4. Why 3 cims over just 2?

1. The CIM to CIM pulley is the best compromise to achieve the most compact pulley cluster. That is to say, with that layout, the pulley reductions take up the width of 2 belts, while allowing sufficient wrap on all pulleys to transmit power. The layout does put a little bit more load on the CIM's shafts, but its negligible given that the outer motor is being pulled in 2 directions.

2. The shifting cluster size is optimized by mounting the actuators (Bimba Flat-I) backwards, with the piston arm attaching to the back plate. When the pistons actuates, the bodies of the pistons come out and bring the linkage out with it to pull the shifter shaft.

3. Weight without CIMs is 2.01 lbs, about 913 grams.

4. 3 CIMs of course have more power than 2 CIMs, and the big thing that that power helps with is capability during pushing matches/when approaching stall.