We only need half of this right?

[Dibit1010]

That's horrible, yikes! But on the bright side if that's an input sprocket you've get a higher ratio....

[Cothron Theiss]

That hurts the soul. Mind sharing how that happened, so I can make sure my team never ever does it?

[Kevin Sevcik]

We did that on our input arm. MiniCIM into a 30:1 VP, into a 20 tooth pinion mated with a 64 tooth gear on the arm. The miniCIM + VP is very close to shearing a tooth at stall. When you backdrive the mechanism by dropping the arm on top of a divider with the weight of the robot, it shears teeth before backdriving.

Our solution is a lot of work for me. We're switching to steel 10DP gears, that I have to machine down to the same face width and with a versakey pattern. If that doesn't work, we're switching to a set of the same steel gears I'm leaving at the full 1" face width. That should move the failure point to the output shaft itself.

[Chris is me]

Originally Posted by Kevin Sevcik

We did that on our input arm. MiniCIM into a 30:1 VP, into a 20 tooth pinion mated with a 64 tooth gear on the arm. The miniCIM + VP is very close to shearing a tooth at stall. When you backdrive the mechanism by dropping the arm on top of a divider with the weight of the robot, it shears teeth before backdriving.

Our solution is a lot of work for me. We're switching to steel 10DP gears, that I have to machine down to the same face width and with a versakey pattern. If that doesn't work, we're switching to a set of the same steel gears I'm leaving at the full 1" face width. That should move the failure point to the output shaft itself.

Why not "just" switch to 35 or even 25 chain? Gear drives for arms are going to have this problem a lot just because the full load of the arm will be carried by just 1 or 2 teeth at a time, versus several wider teeth in a chain setup. Learned this lesson the hard way in 2013 and 2014.

[GDB]

Originally Posted by Cothron Theiss

That hurts the soul. Mind sharing how that happened, so I can make sure my team never ever does it?

I will be honest... our bot is really tight this year.



And if our chain is loose, the motors will start to torque the gearbox and slowly grind the gear on each other, breaking the teeth off!

If you need more pictures of our bot I can give you some. We also have the reveal video. Our 4 drive CIMs are super close this year as well...

[GDB]

Oh I also forgot to mention there was an extra additional 1/16th inch spacer in the gearbox.

[IronicDeadBird]

That half a gear is very well punctuated by the 72dpi 3042 by 4032 resolution.... Why can't we highlight image post combos yet?

[GreyingJay]

You should mount that on a plaque and turn it into a team award.

The "what really grinds my gears" award goes to....