Quote:
Originally Posted by yarden.saa
It's only an assumption - I may be right or wrong:
The failing gearbox was the right one. Our robot design was not 100 precent perfect so if the driver was trying to cross the ramparts a little bit to the right, the robot will stuck and will probably get a strong counterforce as shown in this video.
A better assumption can be that the torqe transferd from the wheels was too high (8" wheels with 9.52:1 gearbox reduction).
Our lesson is that we should have replaced the small aluminium gear with steel gear.
Another photo of the gear http://imgur.com/zBgXDW3 |
It doesn't really look like the gear was too weak from the pictures you've posted. It looks more like wear was the problem. The tooth profile on the large idler gear in that picture is exactly what you'd see if the gears were running in aluminum dust for a while. Clean lubrication keeps that from happening.
If the issue was that the gear itself was too weak to handle the load, I'd expect the failure to look like this:
https://www.chiefdelphi.com/media/photos/43700 . Usually if you overload a gear, you'll shear teeth off of it, but if you run a gearbox without enough lubrication then you'll make dust and wear out the teeth like in the photos you posted.
Open gearboxes are great for FRC since you can look at the gears and see if there's not enough grease or if the grease is dirty. That's the only thing I don't really like about the molded vexpro gearboxes, but all of the other benefits make up for it. Watch your gears often and keep them greased!