I am doing a product analysis for a my college course and I have chosen a the versa Planetary v2 gearbox. If you could share pictures of them failing and describe the loading conditions during failure I would really appreciate it.
We haven’t personally broken any, but word on the street is that the 10:1 stages are broken the most, typically in climbers, and I suspect teams were not following VEX’s recommended load limits.
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Page 42 of the VP Load Rating guide has some information on the various failure conditions of the gearbox that may be useful to you.
I got all of that information. I am hoping to get pictures of really world failures.
No photos, but we repeatedly broke 7:1 stages in 2019. We had a 775 pro driving a 3:1 belt reduction, into a 7:1 VP stage, before the 7:1 stage we broke. So, 27:1 off a 775 Pro before the 7:1 that broke. The failure mode was teeth shearing off the sun gear. It would happen regularly after about a 12-20 climbs. She sheared sun gear tooth/teeth would then take out the ring gear teeth as well, trashing the ring for that stage.
We have broken a number of these. Mostly in climbers and in situations where the gearboxes move something with a hard stop.
We used them in our climber mechanism both during steamworks and powerup. For Steamworks we were using 2 motors in opposition with a 1/2 inch rachet. We ran into two problems that resulted in the gearboxes failing. First we would forget to switch the wratcheting wrench before turning the motors in one direction or the other and the internal gears would strip, and second, one of the two motors running the device would be run the wrong way and whichever of the two gearboxes was weaker would break. Finally they did just give out after a certain number of climbs.
Steamworks year we bought a bunch of spares and tried hard not to screw up, and power up year we ended up going with a different solution after a number of mess-ups.
I don’t have much laying around from back then, but I can look, and if I can find a stripped out gearbox or two PM me and I’ll try to drop it in the mail.
Edoga
Most of our failures were planet gears seizing on the spider. Not very photo worthy.
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I know I had a 10:1 sun gear completely shear off. I can probably get a picture tmmr.
I wasn’t able to find it unfortunately, sorry.
Most of the VP failures we have had are the motor mounting plates breaking, not the stages themselves failing.
We had a shooter prototype that vibrated so heavily that the VP attached to it fell to pieces. Surprisingly, the only permanent failure was 2 of the pins in the planetary carrier coming out.
We just had the same failure tonight on a single stage 3:1 driven by a BAG. Was not a high load application either.
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