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Unread 24-06-2016, 19:11
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Mark Sheridan Mark Sheridan is offline
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FRC #3476 (Code Orange)
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Join Date: Mar 2010
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Re: pic: Another Belt-In-Tube Drivetrain

Quote:
Originally Posted by Cothron Theiss View Post
Do you mind providing details on what parts you were using and how it failed? The 18t VexPro timing pulleys are plenty strong enough for use in an FRC drivetrain under normal conditions, but as Chris explained earlier, there must have been some slippage and racheting going on that lead to your failure.
No slippage or ratcheting. We have good control on build quality to get our Center to center right. its was overloading with too many cycles and the belts snapped on our drive. Our practice bot easily runs 100 simulated matches in a week. So we always have the practice bot on a lifecycle far ahead of the comp bot to catch these sort of failures.

971 helped us out and pointed out that these belts are being loaded beyond their recommended limits. We built a calculator just to double check belt loading. We also swapped a bunch of belts on the same drive rail and noticed despite the same CC, the tensions were different. We try to reduce belt load and build in tensioners which is what we did this year. The last conversation I had with the students is that we are in the mood of having the drive on the practice bot survive with minimal maintenance for over 1000 simulated matches. we are just sick of worry about this stuff, so keep in mind that perspective.

I think using 22 tooth pulley and 15mm wide GT profile belt will be a step in the right direction for Ty's design, which is pretty sweet.
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