Quote:
Originally Posted by artdutra04
Has either 234 or 612 (or any other team using belts on their drive train) used non-aluminum timing belt sprockets? Or more specifically, has anyone used the SDP/SI (or similar) timing belt sprockets that have an aluminum Fairloc/T-Insert hub embedded inside a polycarbonate timing belt sprocket on a FRC drive train?
I've been using some of these with 5mm pitch belt on the shooter (as shown below) and ball intake on 228's robot this year, and was considering them for the drive train in the future. They are a lot lighter than the aluminum ones (freeing up machining resources for more important things), and at high RPMs are noticeably quieter than roller chain (compared to our Aim High robot).
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During the 2007 and 2008 seasons Team 612 used plastic pulleys with the inserted aluminum hub. Both systems experienced 2 regionals, Championship and multiple off season events and still have yet to show signs of failure. Currently my teams photo gallery is under construction so I don't have any better photos of our 2007 or 2008 drive train, this is all I could find.
http://www.chiefdelphi.com/media/photos/32192
What we recommend using is 15mm wide, 5mm HTD belts. In 2007 we used a different kind of belt, that didn't have any problems, but after testing before 2008 season we determined these belts have the past teeth pattern for the FIRST application. If your team uses Inventor 2009, the loop tool helps calculate the pitch length for the exact belts you need. Also through SDP/SI and BBman they provide belt length calculators on their website to help determine the exact belt you need.
This year we have further improved our design by eliminating the use of a transmission. Not only do we save weight by using belts, we save weight by not using transmissions. We currently are running a 12tooth pulley on our cim motors directly to a 90 tooth pulley on our wheels that were custom made on our CNC.
http://www.chiefdelphi.com/media/photos/32600
If your at New Jersey, VCU or Championship and have any questions about belt drives, stop by 612's pit and will be happy to answer or explain how we use belts on our drive train.