pic: 114 New Gearbox Design

That’d be pretty interesting, if you could get one gearbox on either end. Probably break a lot of belts though. Having both on one end would need some decent displacing by a battery.

This isn’t THE gearbox, it’s simply one of maybe three designs we’re looking at. I was asked to design a single Big CIM gearbox, and so it was designed. An upcoming field test between two drive systems with equal speed but different motor choice should reveal which motor will end up better.

i would love to see these worked into the outbaack treads, and I’m sure Sam would also love to see this, were you planning on having 2 per side or just 1?
I know that running the two motors into 1 transmission actually cuts down on efficiency… thinking those treads could push any harder is sorta mind blowing,
awesome design :slight_smile:

Running two of the same motor has no inefficiency. Running two different motors (at matched speeds) have some, but it can be minimized by close matching.

Either way, two decent drive motors (small/big CIM, FP) will be more powerful than any single motor.

But when it comes to any 2 DC motors you can’t get them to be exactly the same. Even if they are the same model so there will be some efficiency loss. However it is insignificant so it really doesn’t matter.

uhm… just wondering, but why are you calculating everything out based on one point along the motor’s torque curve? Personally, I just find a spot that makes me happy (and the Victor drive happy) and use that as my torque numbers at that rated speed… then i rate my top speed at just rolling friction, etc, watching what current i’m at, etc…

I RapidShare’d the torque specs for the 2.5" cim. I’ll see if i can dig up my copy of the 3" cim torque curve. Post with ?'s or //s.



To make this whole process easier, I just use JVN’s design calculator. Go under the simulator section, enter your motor specs and the robot stats (wheel size, friction, weight, etc…) and it will provide some wonderful graphs about the performance of your drivetrain.

It can also do a bunch of other cool things.

Check it out if you’re ever designing ANYTHING on a FIRST robot that has a motor and reduction; it will help immensely.

Thanks JVN

Neato, thanks! Now i have to figure out how to keep the guys in the robotics club (guys learining how to build robots) from finding this… :rolleyes:


Don’t thank me, Thank JVN… I keep hearing around here that he’s a dweeb… but he makes some cool stuff :cool: