Bane Bots transmission sieze

[Demothesis]

We were almost taken out at regionals becasue one of our bane bots transmissions/gearboxes seized up. This ran one of our main drive wheels. We found a replacement and "greased it up good," which fixed our problem.

However, our team was wondering if there was a way to fix our new greased transmission if it were to seize again. Any thoughts? Empirical knowledge?

Thanks, Demothesis

[ZZII 527]

Did you get a chance to really inspect the seized gearbox to see exactly what was binding? There was a thread earlier in the season about the second stage sun gear binding up and that had a lot of good tips for avoiding this:

http://www.chiefdelphi.com/forums/showthread.php?t=53427

Generally, avoid side loads (support the other side of the output shafts), lubricate well, check for full engagement of the output shaft with the plate (sometimes the little spacer rings are missing and the shaft only goes part way into the final stage), and break them in before running at load. (Current draw should drop after a few minutes of running freely to 2.5A or less per motor.) Also, I think several teams have cut the shaft that the sun gear rides on completely and just let it float.

After we installed new carriers, one of our transmissions went back together no problem and ran smoothly. The other would be tight at particular angles. The less-than-technical solution was to see which side the planet gears were tight on and try to "persuade" the output shaft in the opposite direction by resting it on a hard surface and tapping with a hammer. Better to prevent the situation altogether than to have to resort to this, though. Good luck!

[kibbs425]

One thing that may help would be to make sure that you are not putting the transmission into a situation that would make it cantilevered. This may not solve the problem completely but it will definitely help with the operation of the transmission and help to extend its life. This would be a preventative measure to hopefully prevent it from seizing. If you can stop it before it seizes again that would be the best thing.

Also it could of been as simple as it was not well lubricated. Lubrication problems is one of the largest problems engineers face. Just check it periodically to make sure its not "dry" and that they gears aren't wearing down. Because the transmission is completely enclosed you may just have to get a good ear on the transmission to listen for abnormal grinding. If this was the case you solved the problem already.

A cantilevered system is on that has one supported end and one unsupported end. So the motor sticking out of the back of the banebots transmission is cantilevered as well as the drive shaft. Putting a bearing or a bushing on the drive shaft will help. For the motor something as simple as placing a zip tie on the motor to the upper rail supports, if your running a kit bot frame setup, will help. Its not the best solution but its something.

I don't have a lot of experience with these bane bots transmissions but from the limited experience I have with them I've found that one of the biggest problems is coming from having the system cantilevered. If you can inspect the old transmission that seized you might be able to get a better understanding of what happened and how to treat the problem from their.

Hopefully this helps.

[dtengineering]

The new carrier plates seem to make all the troubles go away, but here is a tip that might help a team that is stuck with the old carrier plates...

When they deform, or "bowtie" around the shaft, they also increase in thickness. This compresses the whole gear assembly. Putting a shim, as thin as a piece of masking tape sometimes, (note: I mean self-adhesive cellulose-based shim stock... tape is not allowed) between the motor mount plate and the transmission will space the gears out enough to get them running.

Again... this is an emergency fix... putting in the new carrier plates, as detailed in FIRST team updates and on Chief Delphi is the correct, permanent fix. We've been running hardened carrier plates for two regionals now and the trannies work beautifully!

Jason