BaneBots Tranny

[CidTeach]

Hello all,

I would like to share some concerns and experiences with this years BaneBots transmissions. We, like all, skurried to order a few p60's for manipulator and other uses. Once finally received, we cleaned them out, packed them full of quality grease, and bench tested them, as well as broke them in for ~1hr. Then we opened them back up, inspected, cleaned and repacked em. tested and installed them. This is a typical part of our build season, done with everything including AM tough boxes, our super duper super shifters etc.
When our drive team was practicing, light duty stuff, open field no competition, we noticed that the end plate had a tendency to shift slightly and then noticed phantom problems with our autonomous trials. The telescopic arm would not extend at the same rate all the time, at times jammed itself etc. We assumed it was friction and lubed it up and kept practicing. At both of our regionals this year we've had to replace the trannies due to binding - so bad we could not even extend our arm, either manually or tethered. Meanwhile the arm was designed and tested repeatedly, to retract slowly under its own weight ( it was powered up and down obviously).
We noticed the 4 machine screws provided did not reach the base mounting plate, only catching 2 threads - we upgraded to longer, stronger machine screws which slightly helped, but twisting still occurred.
Then the fatal flaw - the tiny roll pins intended to keep the ring gear stationary, failed/fell out etc, which rendered it useless.
We then spot welded, replaced roll pins, replaced screws, added stiffening plated etc, but the tranny kept binding and creating phantom problems during our matches. Replace and pray became our motto.

The p60's in question were 64:1 with rs775, only for speed reduction and redundancy. An older 16:1 p60 with rs540 used for prototyping worked just fine, but was way to fast.


I would like this thread to serve as a conversational piece for teams who had this problem, or similar. I would also appreciate this not become a ranting thread. Direct experiences please.
We are greatly disappointed with the quality of the newly designed p60's, BaneBots promises and the disservice they provided while being the sole vender of major importance in First this year.

[mwtidd]

Yeah we got the gearboxes we needed for our claw 3 days before ship date.
We ordered them at the end of week 1.
Totally killed any opportunities to go through claw iterations...

[MrForbes]

You're not the only ones with this problem. See how one team fixed theirs

http://www.chiefdelphi.com/forums/sh...ad.php?t=93329

[s_forbes]

Any chance you can post a picture/description of your mechanism? Did you have any failure of the internal components, or was it entirely an issue with the case shifting and causing binding? Any idea how many cycles it took? Nice to know for reference... we're kind of banking on these to bail us out of issues we have with one of our mechanisms, if it ever gets here.

[CidTeach]

here it is. simple nested tubes, #25 chain rack and pinion. delrin rod was machined as bushings between sections. the older black and gold colored banebots tranny 16:1 with a 540 made them fly out of one another, even when loaded with weight. we only beefed up to avoid entanglement damage and slowing down purposes. i hope you have extra's. we planned on other bots causing damage, not shoddy equip.

cycles - up/down for each tube. practice ~50 cycles.
match play @ regionals ~6/match.

[s_forbes]

Thanks for the great info!

The transmission we have currently on the bot is a 64:1 36mm Banebots transmission (the black one from 2007 kit of parts) to open/close our claw. Not a lot of torque, but a lot of cyclical loading. Haven't gotten a decent cycle count on them yet, but I'd guess we eat through them after about 100-200 cycles of the claw. Mechanism pic and failure mode are shown in pictures... double-d interface in output carrier plate fails. Hardened output shaft is always fine.

Our current "solution": swap out the carrier plates when they wear out. Each transmission has 3, so we have a few spares. (but if anyone has more, we're willing to whip out the cash)

We were hoping this issue would go away with P60 since it has larger shaft diameter and hardened plates. Looks like case strength is the weakness of the new design though... not happy news. Shipping delays will keep us eating through the 36mm trannies for our first regional anyway, so we have time to find another solution.


First thing that comes to mind to fix the P60 twisting issue: Get piece of 1.75"x1.75", 0.125" wall aluminum tube and slip over entire tranny (machine things down to fit as necessary). Attach to bearing blocks at both ends through the 8 tapped mounting holes. Should prevent both blocks from rotating relative to one another, but probably won't stop the roll pin shearing issue.

[MrForbes]

How is it controlled...does it speed up and slow down gradually at the ends, or just kind of turn on and off? The transmissions seem to be very susceptible to shock loading.

[CidTeach]

probably not clear in my first few small pics, but a 1/8" AL plate across the top/bottom with 4 holes, plus longer screws handles the twisting there. The roll pins were a cheap and dirty attempt - Bad banebots, Bad! The weld held up nice, with no noticeable internal distortion - if you can control the heat input.

my major gripe is, why these problems with the huge delay and not so cheap $$tag.