Has anyone else had any problems with any of the planet gears from their Versa Planetary v2 transmissions seizing up in the middle of running a motor?
This has happened twice this week on seperate shooter prototype desings. One had two 4" Colsons on a shaft, and the other had eight 4" colsons on the shaft. Both were using 775 pros.
We ran the wheels at the speed we wanted multiple times to test shooting consistency with the PID, and after a while, the wheel completely locked up while the wheel is in motion and causes a sudden stop.
Both times this has happened, we opened the transmissions and found that exactly one of the planet gears got completely stuck on its pinion and we cannot get it unstuck. This has only happened on 3:1 v2 transmissions so far.
We’re wondering if this is a manufacturing flaw that isn’t just happening to us.
I haven’t used 3:1 this year, but I have a few questions/suggestions. Did you properly grease the gearboxes? Did you support the shaft well (i.e. no radial load on the shaft)? Was there any axial load away from the VP? I have heard that all three of these can cause failures.
Pre-grease only. Tried to spin from power supply to break in the motors, pulled way too much power for a single stage. Tried to spin by hand, knew something wasn’t right. Found one planet siezed. Swapped in another 3:1 and it’s much smoother, but we haven’t put any load on it yet. Recently purchased after kickoff.
We’ve been having some issues with VersaPlanteries this year. What fixed most of the binding was taking 2 planet gears and flipping them over then reinstalling them. That and letting the gearboxes burn in at a low speed for a few minutes.
We are running the same 3:1 ratio in the v1 gearboxs with 775 pros without issue, we used the very same gearboxes all 2016 season(5 competitions) with regular 775’s and only had one set screw come loose other than that no problems, we haven’t bought any of the V2 versaplanterary’s yet
Check that the pins on the carrier plate haven’t moved. We had trouble with them popping out slightly and seizing in 2015 and ended up having to weld them in (Pretty sure VexPro suggested this when we contacted them). We used the v1’s, but the v2’s still don’t have welded pins.
This was under pretty high torque though, which it sounds like yours aren’t. Just a suggestion.
This was an issue we had last year as well, but we were also pushing their load limits. After speaking with several teams at worlds, and JVN, the most common recommendation was to weld the carrier plate pins so they couldn’t slide out of the plate.
We experienced similar issues today. BRAND NEW 3:1 stage.
1x775 into a 3:1, single stage VP.
Just as you are describing, a single planet began to seize on its pin. The seized planet was even swapped for used planet gear from 2016 with the exact same results. The transmission almost immediately began to seize from the same pin.
The gearbox was reassembled multiple times by different people and was properly greased. Maybe it’s time to explore needle bearings…
We had a problem with a brand new 3:1 not fitting into the ring gear correctly. We had bought two so we tried the other one without incident. Swapped them out and the problem stayed with 3:1 not the ring.
I contacted VEX and they shipped a new one out ASAP and requested the bad one be returned (on their dime). New one works perfect.
Please stress to your students that if they don’t go together easy and can be hand turned inside the ring gear, they may have an out of spec 3:1.
Contact VEX if you get some bad ones. Great folks and great service.
We have been having issues with 3:1 reductions as well.
One of ours was obviously made out of spec (one gear couldn’t move at all, couldn’t be removed from shaft) and the other was having binding issues.
We just used 4:1s, and they worked fine IIRC.
I just want to reiterate this. FRC suppliers (especially VEX/IFI, AndyMark, Rev) are generally very helpful if you reach out to them with a polite email. A lot of the people at these places are passionate about FIRST and want to see teams using their stuff succeed. The five minutes it takes to write an email to them can really help with solving many issues.
I’ll start by saying if you think you have a problem, call (or email, [email protected]) us.
We have had a few reported cases of 3:1 gear kits having seized gears or being a very tight fit in the ring gear. In most cases of a tight fitting 3:1 gear kit it’s a combination of the gear kit being toward the high side of the tolerance and the anodizing on the ring gear being a little thicker. This is easily solved with a run in.
I’ve seen two cases of gears seizing on pins. One was from a bur on the bore of the gear. The other was from a crooked pin on the carrier. I’ve yet to see any cases where the pin or bore on the gear were out of tolerance.
In some reported cases we’ve been able to fix the issue and in others we’ve replaced the gear kit.
Here are a couple recommendations I have if you have a tight fitting 3:1 gear kit:
Make sure there’s no dirt or large debris on the gear teeth.
Run the gearbox in, lubricated, for 30-60 minutes. All gearboxes need to be run in at some point. In some cases (ex: the transmission in your car) they do the run in at the factory. However, due to the modular nature of the VersaPlanetary we do not have that luxury. Note: Lubricated does not mean packed full of grease. You can over lubricate a gearbox.