I was wondering if any teams would be willing to share their experiences with the Versplateray Lite gearboxes on competition FRC robots this year. The benefits of it are cost ($36 savings compared to a regular Versaplanetary for. 2-stage setup) and weight (0.16 pounds for a 2-stage). A drawback is there is no side-mounting holes. Another potential drawback is the durability of them. I know there are published load ratings ( https://content.vexrobotics.com/vexpro/pdf/VersaPlanetaryLite-LoadRatings-20171211.pdf ). For teams that worked within these load ratings, did you experience any failures? One potential area of concern would be the metal planetary gear teeth wearing out the plastic ring gears. Another would be the plastic threads for mounting and holding the gearbox together not standing up to the test of time or too aggressive tightening.
We used the VP Lites on our “gripper” mechanism (the second half of the #teamhandoff handoff). 775pro with a ~20:1 reduction (I forget the exact ratio). We didn’t have any problems with them all season, even though they were assembled incorrectly for the first week of testing. Would definitely use for light mechanisms again
Used them to power our cube infeed (BAG motor, 10:1?) and cube handling mechanism (775 Pro, 7:1?). The infeed motors were outside of our frame for most of the match, took a ton of hits from other robots, were stalled against field walls, and lots of other nonsense. They did not fail one time.
We were genuinely impressed with their robustness. To be honest, I have no idea what the inside of the plastic ring gears looks like at this point because we’ve had no reason to tear one down. Perhaps we’ll do that at the next meeting and report back.
We used the VP Lites on our intake this year, and they worked out great. My only issue was they were not a 100% drop-in replacement for the metal ones because they (the Lites) use #8-32 mounting screws rather than #10-32. The intake was originally designed and manufactured for the metal ones, but we were unable to get more of the metal mounts, so we went with the Lites. We had a bit sloppy mount. As far as durability goes, I had no complaints in this application. We even used the plastic ring gears with a BAG and 7:1 reduction without issue (again, in this application), and I’d definitely use them again.
The only issues we had with the two Versaplanetary Lites we used on our intake was that the motor plate mounting screws didn’t attach the motor plate to the gearbox very securely, so we ended up tightening them a lot.
Even when they were tightened, there was quite a bit of play in the mounting such that you could deflect the motor relative to the gearbox by a few degrees.
We also had an issue with the motor set screw coming loose, but I blame this on a lack of loctite on our part.
Beyond that, the only other complaint I have is that the threaded standoffs that the screws attach to have a tendency to fall out during assembly (and are easy to loose) though this isn’t a deal-breaker, just mildly frustrating.
Overall I’d certainly consider using them again for light uses like intakes and such. I do wish they had a 1/2" Hex output shaft option in the configuration though, since replacing the shafts seems to lead to sub-par mounting due to the difficulty of reinstalling the snap-ring correctly, and the 1/2" Hex output makes them much more of a drop-in replacement for a regular Versaplanetary for us (we use 1/2" Hex almost exclusively).
The two Versaplanetary Lites we used on our intake held up well overall, even in spite of the abuse we put them through (our intake rollers ran constantly, even while holding cubes, and when grabbing cubes would run a “power pulse” program that would alternate the motor power between 60% and 100% every 0.3 seconds). The few times we’ve had them open I’ve observed no noticeable wear to the ring gears.
Our lites had zero trouble with durability on our intakes but I will agree that the screws that attached the motor and the gearbox itself required constant tightening.
Not a deal breaker but make sure you make provisions for easy assess to these screws in your designs.
Just to clarify, the mounting holes for the VP lites’ are not just tapped plastic, they have small 8-32 metal standoffs inserted in the plastic. As others have mentioned, these can be a bit frustrating at times due to them falling out during assembly, and the fact that they’re not 10-32 like the metal ones means they’re not a perfect drop in replacement for them.
We’ve also experienced the flex in the gearboxes/motors that a few others have described above. This come from only two 8-32 bolts being used to mount the gearbox, along with only two used to mount the motors. The two unsecured corners is where all the flex comes from.
The last issue that I’ve had with the lite variant is that when you order, take note that the only mounting hardware included is for the bag motor. So if you want to mount any other style of motor, the price goes up. Enough that I personally would consider getting the metal ones instead (assuming the weight isn’t one of your reasons for the lite).
Other than those issues though, the actual durability we found to be quite good. When used correctly, we didn’t have one actually fail on us.
We used them on our first intake design, and despite haveing them in a vulnerable spot we only ended up with a small crack after thr first event. However, we used the custom length shaft female end whatever its called and hated it. We had a hard time keeping it tight for match even with loctite. My advice, go with the normal output shafts you should be golden.
We had a similar issue initially. The set screw just isn’t enough to hold the shaft in under the conditions of a direct drive, vertical shaft intake. The weight of the cube proves too much over time. To fix the problem, we marked the shaft and drilled a clearance hole in it. Then we grabbed a much longer set screw and stuck it through the hole (with loctite). That way you aren’t just relying on the friction from the set screw to hold it in place - something would actually need to break.
I would NOT recommend that under heavy load conditions (like on a climber) as it weakens the shaft. But we didn’t have any issues with it on the intake - 2 regionals, champs, states, 1 off-season, and several all-day demo’s and it’s still going strong.
Using the female adapter in another locations, you can make sure it doesn’t come out of the shaft in other ways. Our elevator winch was made with two AndyMark wheel hubs. We simply bolted straight through one of them to secure the shaft, letting the bearing on the other side keep the shaft from pulling out. Easy, no problems there either!
According to Vex, the primary failure mode was the ring gear on high torque. This is not surprising, as all the torque gained by reduction is provided by the ring gear. I expect that it would come apart under tension where there is little corner material to reinforce it, in the gap between a couple of teeth. Most likely this would be on the leading side of one of the screw mounts, where the corner part of the ring gear gets small or nonexistent because the ring gear is more securely held, and the other thin spots would be able to relieve the tension through flexing. That is, one of the thin spots highlighted in the image, with the red areas most likely for clockwise rotation and green for counter-clockwise. I still wouldn’t rule out the blue ones for either direction, because the material is even thinner there, and at a more sharply defined location, enabling stress to focus at that point.
We used them on our intake this year as well with 775Pros, I don’t remember the ratio we ended up with but it was either 7:1 or 9:1. I was pretty happy with the performance, I don’t think we had any issues with the gearboxes themselves.
As other have mentioned, the mounting was a continual issue. In addition to the standoffs dropping and getting lost, we stripped out the molded hex in the plastic on at least two input blocks. When we disassemble the practice robot, we will probably open them up to see what the internals look like after a season of runtime.
We’ll definitely use VP Lites in the future for cost and weight considerations, and if the mounting gets improved I’d be inclined to use them in more locations.
we used 2 rs550s with a 10:1 on our intake we had no problems with them other than they don’t come in a .5" hex output as for the durability on the ring gears its glass fiber reinforced nylon so its unlikely to melt but they have rather low impact resistance so be careful not to hit it to hard but from our experience they are still pretty strong.
p.s. the mounting holes and motor mounting holes are all aluminum inserts so don’t worry about strength just be warned when assembling they like to fall out and get lost be and careful to check them once in a while to make sure their still tight and don’t over torque them
We managed to break one during a FIMsteins practice match, it wasnt an official match so there is no video to look back at. We essentially went to go intake a cube from the pyramid, and as we backed out, our gearbox was just hanging by the wires. It appeared to have broke right at the base. That was the only issue during the season, and due to the type of failure, it may have taken a physical impact.
We ordered some more 1/2" Hex shafts that we swapped in to allow us to use a more rigid pulley setup. We originally ran plastic 3/8 Hex GT2 pulleys on the gearboxes but eventually went to an aluminum pulley.
