Quote:
Originally Posted by Oblarg
Yes, but they're far more forgiving of minor alignment slop, and you don't have to worry about integer numbers of links, and they don't stretch.
I've done four drives with belt in my time in FRC, and I think four or five with chain. I've seen at least an order of magnitude more problems with the latter.
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I disagree with all three of your claims.
1. You can run chain considerably looser than exact C-C (because of alignment slop), and it will work, though it will be noisy/sloppy. It will continue to transmit torque until it is loose enough for the chain to slide off of a tooth, which requires the chain to be quite loose. Belts will slip if there is slop or if the center to center is to small, and snap if they are too tight. Chain is much more tolerant of C-C misalignment.
2. I don't understand this comment. Belts require an integer number of grooves/teeth, and chain does too. I don't see how this can be an advantage of either.
3. Belts stretch, but admittedly, less than chains.
I have been in charge of drive chain on the past 6 robots I've been involved with. We have never had a single issue. We've never broken a chain, as they're rated for considerably larger loads than belts, we never thrown a chain on a competition robot, as we always cover them and ensure sprockets are aligned, and we've never had any other failures. We haven't always had access to great machining resources, and we've never had a problem.
I have been in charge of one belt drive, so I realize my experience with them is limited, but they're thicker, they slip, and we had a belt snap. So we're going back to chains.
On the original topic, I find that putting in a floating idler sprocket, like this (
http://www.team228.org/gallery/106/s...998-37b1e.jpg), is the way to go for chain. If you want it tighter, move it closer to the smaller sprocket, and if you want it looser, move it away. It's easy, cheap, light and adjustable.