We’ve never used belts outside of the KOP drivetrain and are wondering if the GT2 belts are okay for a shooter going 5-9000 RPM. They say “low load” situations but do not define what that means.
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I think it also depends on how much pressure you are putting on the belts and for how long they will be spinning at that speed. I don’t know if they could handle that. Did you try looking at the tech notes for the belts?
I looked at it but am not sure if the answer is in there. This is the belt used in the Greyt shooter is the reason I asked.
Yeah, I just finished reading through it too and couldn’t find anything about the durability of the belts. Sorry. I’d think that if the belts were placed in this shooter that they would have the capability to go that high.
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I would recommend reading the actual Gates belt design manual. It is much more informative.
Edit: I think I grabbed the wrong manual, give me a minute to find the right one.
Edit again: I believe this is the one, with a caveat that the VEX belts are nonstandard
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I’d stick to the standard HTD 5 for something like this. From my limited experience playing with the gt2 pulleys and belts, the relative weakness is significant. Id play this one safe, especially in an application with quick momentum changes like a flywheel. What’s the appeal? Space reduction?
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I guess the reason might be there are no HTD pulleys for Falcon splines.
On a serious note, spinning a shooter wheel that fast is… probably not worth it. If you really know what you’re doing with designing a shooter, I won’t stop you, but in all likelihood you won’t get much performance improvement past ~5000 rpm or so. That’s a rough rule of thumb because if your wheel is small enough that you need to be spinning it that fast, the ball probably won’t have enough contact time with the wheel to get up to that speed. If you have a very extreme (like >180 degrees) amount of wrap around the shooter wheel, maybe you can get good results, but in most designs, you’ll be better served by using a bigger wheel or adding more compression to the system so you can run it at a lower speed.
I know it’s not really what you asked, but I’d bet reevaluating some of your other design decisions will help you more in the long run than worrying about the best belt to run with what you have now.
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If we don’t run our shooter direct drive, the second choice would be a GT2 3mm belt reduction for us. My expectation is that we would face any issues doing that.
We’ve also used GT2 3mm for reductions directly from a 775pro (Free Speed ~18,000rpm) for our intakes in the past.
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In 2017 we ran multiple systems with GT2 belts directly connected to 775s. I think we had our shooter geared 2:1 originally with 2 motors (bad design) and never had any issues with belts. We also had our feeder geared like 5:1 and our intake 4:1 I believe that year, iirc, we never broke a belt.
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This might help
https://www.sdp-si.com/D265/PDF/D265T146.pdf
GT2 comes in 2, 3 and 5mm indicated as a GT2-2 or GT2-3 etc. Now the 2mm and 3mm variety should handle it but then as you can see from the charts it also depends on the torque at the rpm and other factors like the number of teeth, belt width etc - read the pdf. HTH
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Vexpro sells 16 tooth GT2 3mm pitch pulleys for 9mm wide belt made to press fit into a 775 pro motor. Keep in mind their free speed is over 18,000 RPM.
While it’s possible that your shooter is “out of spec” according to Gates, it will still work. Gates spec’s their products to last an industrial grade product lifetime, and your robot use will never even approach a fraction of that expected lifetime.
TLDR: Yes it will work, just make sure you aren’t skipping teeth and breaking belt that way.
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