If anyone is using 2 falcon 500s in a gearbox and has aluminum gearing I highly recommend swapping them out for steel gears. At the la regional my team 4501 fully stripped 2 20dp 20t aluminum spur gears. At the same event 2637 using aluminum gears in a dual falcon 500 gearbox also stripped their 14t gear. It may only be for the small gears but if you have the weight I highly recommend swapping all the gearing out. If not, at least do it for the small gears. WCP is currently in stock in most steel gearing. We checked before our last match as this had just happened on the other side of our gearbox and the gear was fine. This is what it looked like after that match.
Some people asked for gearing specifics. We are using the wcp ss flipped gearboxes with 2 falcons and 10t steel falcon pinions. Gearing is 10:60 20:36 32:34 the 20t is the one that shredded
I suspect something else may be contributing to your problem. We have been running falcons on 6 different drivetrain transmissions (3 falcons to each transmission) and various other sub-mechanisms with no problem.
One of our gears got chewed up a bit when the falcon mounting bolts were loose - but that was it.
We had gears end up looking like that when they didn’t get greased years ago with Cims.
Edit to add: we have avoided the rendezvous except when absolutely necessary. It wouldn’t surprise me to find out it’s taking a toll on some robots. But that really isn’t due to the type of motor in use.
I am certain there is another root cause though we have taken apart both sides of the drivetrain since this happened and could not identify any issue. I have watched the match videos for the moment the drivetrain stops and in that last match we never went over the rendezvous at any kind of speed so I’m hesitant to blame that as in our testing before competition we tested hitting the rendezvous pretty hard and didn’t see anything like this. I think the point still stands though that falcons are capable of ripping through aluminum gears and that they should be swapped if possible to steel.
We utilize velocity control on our drivetrains and they will actually apply reverse power to stop on the spot when the joysticks are released. Using the brake function should not have any negative effects.
Hmmm that actually could be it. We weren’t liking how Drifty the drivetrain felt, so we enabled break for the second day, which is when all this happened. Do any of the other teams that had this happen know if they had brake enabled?
Any motor combo is capable of ripping through aluminum gears. You have to be careful using them. Double check your code to see if the motors are fighting each other since that could be a possible reason.
My team (5113) also had aluminum gears in our gearbox for our 4 falcon gearbox. In the last seconds of the semifinal match for our first district event this year, one of the sides of the drivetrain stopped moving, due to one of the big gears being completely stripped. We are now switching to steel gears. Given, we would also drive at 14 f/s over the rendezvous zone, which might have contributed, but I digress.
We thought that could be a reason after the first one ripped but in the code and on the indicator lights on the motor itself they aren’t fighting. Yeah we learned a lesson and at least for the small gears we are going to use steel. We have a pretty light robot this year so can afford it.
So the team I am referencing switched from all motors being in break to just one and that seemed to provide them what they wanted.
Though it may not be the real reason this happened as @Tom_Line mentions. This is just something that was recommended to us by another team. We are doing coast, and enabling break only in specific situations.
We opted for steel gears in our drivetrain this year to reduce this risk anyway, but I’m curious…
@Tom_Line, could you share specifics of your gearbox? (i.e., # of stages, ratios / if shifting) Are you saying all your drivetrain gears are aluminum?
@ChymeRu, I would most suspect either 1) inadequate grease/lubrication or 2) mediocre gear mesh. Which gears failed? If it’s in the final stage of your gearing, I’d suspect it is some combination of too much torque/power (for the strength of the gear) and the above 2 possibilities… Obviously you’d want to know if your motors were fighting each other, but I expect you’d see other problems first and you’d probably lose teeth on your motor pinions first.
In a high torque and speed application like the drivetrain - particularly with likelihood of high dynamic loading - a relatively small gear wear or tooth damage could quickly propagate to fully stripped teeth.
For the second part that is why we were rather confused. It’s In the middle stage of three and it’s in the wcp ss flipped gearbox. The falcon pinions are steel so even if that’s where most of the old is I doubt they would snap before another aluminum gear. The gearing in our gearbox is 10:60, 20:36, 32:34
We are going to switch to steel anyway as we have the weight to spare and it would shift our center of mass slightly which we wanted anyway. Also, we are going to look into a better grease/method of greasing though I am fairly confident in the grease that was on before these matches. Thank you for the ideas everyone!
That happened to us when we did a 8 motor (4x CIM + Mini CIM) mecanum drivetrain. The problem was that the frame was flexing and causing the teeth to wear out. It was resolved by adding another reinforcement plate on the gearbox
We had a stripped 60T gear also before our first event, but I believe the problem originated from the 10T pinions and their weird tooth profile. Changed them for 12T and our drivetrain got beaten pretty bad at QCSH, no sign of wear.
