Timing Belts for 6W Drive

[=Martin=Taylor=]

The statement that belts cannot handle high torque is false. Lots of machines like large mills and motorcycles use belts without any trouble.

The problem with belts is that they are not good at changing directions quickly. Often, when they go from forwards to reverse very quickly, (as in a FIRST robot) they skip teeth or go flying off.

Notice how 118 only needs to drive their wheels 1 direction?

[Brandon Holley]

We ordered our belts from http://www.sdp-si.com/. They are a reliable source, equivalent to any kind of supplier. They offer a large variety of sizes, lengths, and materials in both the pulley and the actual belt.

[markulrich]

Sounds like with timing belts it's harder to order the right thing and set-up, but may be more durable and not need tensioning.

Originally Posted by Teched3

I would also suggest using a COTS belt rather than try to put a custom length onto your machine.

We have also used the drive configuration you are considering, but would suggest runnng the wheel to wheel belt from the mid wheel to the front, rather than the rear.

What is a COTS belt? Great suggestion with having transmissions in back, will do.

[Vikesrock]

Originally Posted by markulrich

Sounds like with timing belts it's harder to order the right thing and set-up, but may be more durable and not need tensioning.



What is a COTS belt? Great suggestion with having transmissions in back, will do.

COTS stands for Commercial-Off-The-Shelf. The alternative would be a custom length belt.

[Big Ideas]

Properly installed chain is definitely more efficient then timing belt (or any other drive system). That's why bicycles have gone back to chain time and again. Should be less expensive also. You don't have to order the right length. You don't have to compromise your design to fit an available belt length. Splicing a continuous loop belt is not easy to do well and lowers the strength, torque rating, and durability. You can break chain to remove/install with other drive elements still in place. Timing belts have advantages for noise, accuracy, longevity, low maintenance, set and forget, as well as a back surface that can transport objects.

V belt is less efficient than timing belts.
Steve des Jardins
Mentor Team #2102

[Brandon Holley]

Originally Posted by Big Ideas

Properly installed chain is definitely more efficient then timing belt (or any other drive system). That's why bicycles have gone back to chain time and again. Should be less expensive also. You don't have to order the right length. You don't have to compromise your design to fit an available belt length. Splicing a continuous loop belt is not easy to do well and lowers the strength, torque rating, and durability. You can break chain to remove/install with other drive elements still in place. Timing belts have advantages for noise, accuracy, longevity, low maintenance, set and forget, as well as a back surface that can transport objects.

I bet you would be surprised by how many different lengths timing belts come in. They come in very small increments (on average about .05" increments) from 2.8" up to 220", so you really aren't "compromising" to fit an available belt length.

https://sdp-si.com/eStore/Direct.asp?GroupID=213


I would definitely not recommend trying to splice your own belt for the reason you stated involving lower strength, torque rating and durability.

I've said it before, and I'll say it again, I think if teams are interested in belts there really isn't a great reason not to give them a shot. There are pros and cons to each setup (chain vs belts), its really up to the team and how far outside their comfort zone they want to step.



edit: apparently i've hit 1000 posts after ~5 years of browsing CD

Out of curiosity, could some team that has used timing belts with great success post up the type of belt they used (part numbers and so on), possibly with the addition of a picture, so we can all get a clear idea of what's been proven to work?

Also, How much weight is actually saved between a #25 chain vs an equivalent strength belt? And is the cost any different?