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Unread 05-02-2007, 13:18
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Joe Johnson Joe Johnson is offline
Engineer at Medrobotics
AKA: Dr. Joe
FRC #0088 (TJ2)
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Re: BaneBots Gearbox Locking UP

I don't see any reason to have the output shaft go through the sun for stage 2. It may help allign things but I believe that every thing should work without it.

One thing that caught my eye in you post is that the shafts siezed and/or scored. I wonder if the chaft was not smooth to begin with? It is possible that is part of the problem. Also, it is possible that somehow the surface did not get greased properly.

On another note, WaterFreak brings up a very good point. Looking at the parts, I can definitely see that the tabs on the 2-CIM adaptor can cause a jam if one of the planets gets up in the space between the tabs.

One easy fix may be to put a spacer on the cluster gear (over the sun but below the big gear). Here are some washers from McMaster that may work well for this purpose: 98038A268 The ID just fit over the sun and its OD is 1.3" will hold the planets out of the space. I would recommend using another washer below it to keep it spaced out right. If 2 washers work fine, but it looks like the spec as 2 washers being just a bit too thick (we need to space it out by .220" or so and each washer is 0.122-177" too think for 2). I think this wave washer may be just the ticket: 92161A035

I have to call Ed from Banebots on another matter. I will make sure that Banebots is aware of this issue.

UPDATE:
I was just talking to Ed, explaining the problem when I thought, "Hey, wait, isn't there a washer or wearplate already IN that gearbox that would prevent the planets from dropping?" I had done my initial evaluation using a naked carrier, not a whole gearbox assembly. Investigations showed that, yes, there is a washer/wear plate in the gearbox. It may have been stuck up to the aluminum motor mounting plate, but it is there.

You can even see it in Banebot's excellent instructions

"...Once removed, the back plate wil slide off. Make sure that the thin metal separation plate stays with the planetary gearbox as shown"

FYI

Joe J.
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Last edited by Joe Johnson : 05-02-2007 at 13:39.