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Unread 15-04-2015, 11:12
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Re: Vex Versaplanetary gearbox repair

Quote:
Originally Posted by Dominick Ferone View Post
We made the grove deeper manually with a mini file and widened it slightly to make the snap ring want to glide back down if it were to pull up.

Along with it to try and prevent it from pulling up we tried having the lead screw be pushed down a little and add in some spacers, and switch out the lexan plate with aluminum in the hopes of preventing the lead screw from pulling the shaft in the first place.

If this plan doesn't work the next idea is to add in a spring system so it compresses a spring and bring the lead screw down an 1/8th of an inch instead of pulling the shaft up numerous times and forcing the snap ring down. Also we noticed the cim adapter wasn't flush with the motor so we shortened the output shaft a bit more to sit flatter in hopes of reducing any future failures.

We are open to other ideas to try, as we have a demo this weekend and if the snap ring fails again we will try other ideas next week.
I wouldn't have done that with a file. The depth of the groove matters some, but the squareness of the shoulder matters a lot too. If the shoulder you filed isn't square, it'd basically like its already failed, and it's probably not much better than the original groove.

Honestly, that big bearing block you have bolted to the top should be what you use to stop this. Replace whatever that white disk is with shims to take up all the space between the coupling and the inner race of the bearing. Think lock washers, only without the twist. If you do that, then the leadscrew will only be able to pull up on the coupling and through the coupling the bearing block. Worst case then is you fail at the coupling and the leadscrew pulls out of the coupling, which you should be able to fix with a set screw into a nice sized divot in the leadscrew. If the lexan plate is flexing, then yeah, swapping that for aluminum is a good idea.
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Last edited by Kevin Sevcik : 15-04-2015 at 11:23.