Belt torque loadings

[mman1506]

We are planning to use a 3 cim versaChassis for our drivetrain this year and we are hoping on using a belt drive. Unfortunately without making large cutouts in the the belly pan it would limit us to a 24 tooth pulley on a 9 mm belt and we are worried we would be going over the recommended torque loading.

From the gates documentation it seems that the setup would only be rated for 433 oz.in which is below thew 1000 oz.in the 3 cim drive is rated for especially when accounting for a factor of safety.

Originally Posted by mman1506

We are planning to use a 3 cim versaChassis for our drivetrain this year and we are hoping on using a belt drive. Unfortunately without making large cutouts in the the belly pan it would limit us to a 24 tooth pulley on a 9 mm belt and we are worried we would be going over the recommended torque loading.

From the gates documentation it seems that the setup would only be rated for 433 oz.in which is below thew 1000 oz.in the 3 cim drive is rated for especially when accounting for a factor of safety.

This setup works perfectly fine. We're running this exact same setup and it's been driving beautifully the past few days without a problem. I know many teams ran a similar setup in the offseason (ourselves included) and it worked just as fine then.

[magnets]

You should probably be fine. Your robot will run for maybe 100 hours the whole season, and that 422 oz in torque rating is in place because that belt is designed to be run with that much torque for thousands and thousands of hours.

When doing FRC design with bouncing, vibrating, and crashing robots, it's important that you build in a safety factor for shock loads, but fatigue over thousands of hours isn't usually a problem.

[DonRotolo]

If you still have concerns, built it, weigh it down to 150 lbs, and crash it into a (concrete) wall at full throttle from a foot or two away, repeatedly. If it doesn't fail with 100 such crashes, it'll be fine in competition.

What you are doing is causing a shock load, which quickly brings out weaknesses. You don't want to crash at high speed, but at low speed with high load (full throttle). Crashing into pool noodles is fine, don't need to bend the chassis...