Any fellows engineers here? For an odd and un-named application, I would like to transfer around 500 lbft of torque from one place to another. There will be moderate shock loading, and the max RPM is in the 6000 RPM range. No or very little mechanical advantage is desired. Seems most gilmer style belts give up at a lower RPM. As cheap as possible - oiled or dry, don't care.
Ideas?
-Brian
http://www.gates.com/index.cfm would be a great place to start looking if you're interested in belts. I know they have software that can help you calculate what you want to do and suggest the right bits to make it happen.
In reply to BAMF:
Do you need it to be a timed belt application?
http://www.fennerdrives.com/assets/hpctech_imp.pdf
You can do 5400rpm in the A/13 belt.
The chain used in earlier Olds Toronado FWD transmissions ought to be stout enough. It can handle the torque from a 400+ cube V-8 for 100K+ miles.
In reply to erohslc:
Even held up to GMC motorhome service!
Another thought might be a chain from a 4wd transfer case. Probably a bit more available in a junkyard and already comes in a case with useable sprockets, bearings, and a case that provides power transmission from both ends!
Shawn
Shock load is a problem for chains, belts handle it much better.
V-belts, flat belts, toothed belts and chains will all have problems with 6,000 rpm. You're going to have to run some tight tolerances or use a tensioner, or both. As well some guides to control vibration and flapping.
Spring loaded belt tensioners are common on cars and trucks these days. Getting several from a junk yard and replacing the pulley to suit your needs should let you spin those sort of rpms though.
Many high load, high shock, but lower rpm applications run multiple v-belts. A royal pain to assemble, but once in operation they take the shocks without incident, Properly over-engineered, when a belt or two fails, it doesn't take the machinery down. Look at hay bailers for example.
Foxtrapper: interesting point - multiple belts would be fine. Would you suggest multiple 'timing' belts with extra tensioners? Are there good rules of thumb for tensioning, as far as how inches between etc?
BAMF: Tried that before this place - 6000 RPM is a problem as foxtrapper has noted.
Transmaro: a transfer case is an interesting idea - an interesting idea indeed.
erohslc: got a picture? Part number? That sounds interesting too.
Thanks all.
I hadn't thought of multiple V-belts...but that could be an option. Run like 6 of 'em.
Yes, there are guidelines. And since I don't deal with belt drivetrains much, I'm not up on them. Though Googling gives a few useful sites.
hutchinson transmission online belt calculator
Marathon motors belt selection guidelines
Gilmer belts (like toothed timing belts) don't run tension per se. More like a zeroing of slack, similar to a chain. Where a V-belt transmits power via friction, a gilmer belt transmits power through the cogs, like a link on a chain. Because it's transmitting the load through the teeth on the belt, they can be torn off from a shock load, just like the teeth on a sprocket.
All of those links say it can't be done - hence me coming here.
I am going to reduce the shock loading to "mild" after some discussion.
Who wants to go grab me a couple of TF blower gilmer belts discarded at a national event to experiment with? I'd be totally OK with multiple gilmers. Multiple Vs sounds like tons of bearing stress and lots of loss.
Can you tell us what you are building? I'm not an engineer, have no useful knowledge, but you have me very curious now.
Nope. Smokey, this is not 'Nam... there are rules.
tuna55 wrote: All of those links say it can't be done - hence me coming here.
No, they don't. The first one gives you the values for a single belt. Just multiply the number of belts until you get the power level you want.
I ran it right up to a 200 hp high shock load motor 100% duty cycle 6" pulleys 6,000 rpm.
The others are a set of tables and descriptions. They don't say you can't do it anywhere on them. They just cover a certain range. Extrapolate the line.
my old WoodChuck wood chiper uses 8 CX sized belts runs 1:1 drum to 300 ford 6cyl It used to have two common backed 4 V belts but there $$ so its got indvidual belts now works fine. While not 6000rpm it runs around 5000 and high shock loads when you toss a 6inch log in. Brrr.....brrrr....vroom
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