Experiences with Belting

[Patrick Wang]

I'm curious to know if anyone has had experiences with belting whether for building robot components or not.

Specifically, I would like to know the following.

-How does belting compare to chains or gears for transmission efficiency?

-Have you encountered any general problems with belting in general?

Any other experiences are of course welcome.

I'm mostly looking at using belts for tranmissions and not so much conveyor assemblies if that helps focus things

[sanddrag]

There are many good industrial devices that use belting but the following should be considered:
Pulleys are much more money than sprockets
Belts must be properly tensioned to function correctly
Blets can slip, chains cannot.
That's about as far as my knowledge goes. We've always used chain and sprockets just because there's no real reason not to. They are overall the best in my opinion.

[MBiddy]

Well I think that if your robot is misbehaving, a good belting will put it back in line. Use the biggest, leatheriest belt you have, since it's made of metal. A few team members all using their belts at the same time is enough to make any machine behave.

[sanddrag]

I didn't realize it was you, Patrick, who started this thread. So, how's your transmission project coming anyway?

[Aaron Lussier]

Originally posted by Patrick Wang
-How does belting compare to chains or gears for transmission efficiency?

-Have you encountered any general problems with belting in general?

First I must give you the story of our transmission

Weeks 1-5- Working on a belt systems that could be able to pull two goals and not slip

Week 6 Realized what a dumb idea that was becasue we had so much traction that the belt were slipping. Hurriedly threw together a sproket and chain system that did not switch casue we did not have time to thin of how to do it.

1. 3/8 chain will never break, never slip and strech a lot less that belts

2. One word "Slippage" we could never get them tight enough to hold anything with out popping breakers or just not working.

My opinion go with the chains and gears.

[Rob Colatutto]

we use belts in our tranny between the atwood and the bosch motors. in order for it to work we had to measure it exactly so everything fit perfectly without any tensioners or anything, if you have the time to do all that, its worth it

[Andy A.]

Any kind of belt or chain will slip, if it's not big enough/tight enough for the job.

We used big heavy chain and sprockets for our drive, and as far as I know, it never slipped a tooth.

We also used timing belt on our rollers. Again, as far as I know, they never slipped.

Aside from that, I belive general wisdom is that chain is better for high tourqe situations, belts for high speed (exaclty the situation on our bot).

[Patrick Wang]

Sand,

the transmission project is going along well. As with any engineering challenge however I am now on my 3rd iteration.

Traditionally our team has been using chains and sprockets and we know they work.

I was just curious about the belting because I have seen many variable speed mechanisms work off belting. but at a second glance I don't think that belting would be quite suitable for robot purposes.

Thanks for all the responses!

[Adam Y.]

Hmm belts what an interesting concept if implemented correctly they can be your best friend if not implement correctly they can be a nightmare. Last year we tried to use belt drives on our robot but.... it slipped!!!! Ahhhh. I would think that synchronous belts would be your best bet but get one with a power rating at which the belt wouldn't slip. Btw Ill be back later from marching band Ill explain it better.

[Matt Reiland]

For efficiency I think you will find it very difficult to beat straight cut spur gears in the transmission over either chain or belt. Also there is no tensioning in a properly built gear drive tranny, just bearing supported axles meshing the gears. Again properly designed (right pitch, gear material, and face width) a first robot will show little if any wear after a year with a gear driven tranny.

We have 5 on the 2002 robot, all look brand new and none have failed since they were built in January.

Look into gear drive. Leave the belts on the Harley Davidsons, and the chains on the Crotch Rockets.

[sanddrag]

Everything you said Matt is absolutely correct however I would have to say that nothing beats chains and sprockets for ease of design/assembly and durability.

[JVN]

We used belting for our transmission this year. Our entire tranny consisted of pulley reductions from the chiaphua to the wheels.

It worked fairly well, although it was hard to keep tensioned and aligned properly (especially in the heat of battle). I found myself wishing our head engineers had just built a spur gear box you can't beat ~90% efficiency!

I wouldn't do it again...

~JVN

[Katie Reynolds]

We used belting two years ago on TOBOR IV ... I believe we got it not to slip around the time last year's IRI rolled around

Sprockets/chain all the way!

- Katie

[Sachiel7]

Well, my team had an interesting experience with using belts this past year....
We had many problems, however I'm not 100% convinced this is because of belts.
In my opinion, chains are alot better to use in FIRST, you just MUST spend plenty of time making accurate measurements and making sure everything is lined up exactly perfect.
If you are going to use belts, Make sure you know the size of you belt and order it a good time before shipping. Also, make sure you get extras.
The main prob. with Belts is that you pretty much have to buld a gearbox to go to a shaft to hold the Belt Drive, and that can be pretty painful. you then have to worry about where all your resistance force is going, and need to find a way to keep most of it off the gears. Also, you have to find a creative way to do this with keeping tension on the belts.
But, If you can do this, good luck.
At least with chain, if it breaks, you can fix it. With belts...you'd better have an extra. In fact, this past year, we found out on Day 1 of our reigonal that our leader had ordered the wrong size belt for 2 motors of our dirve sys. Well, we tried to cut them down to size, but they just broke in the first 5 sec. So, we had to scramble the rest of the day to order in the right size. When we finally did, we had to take apart our robot to put them on. During the next match, we found out our tensioning techinique stank, so the belts (and gears) stated happily ripping themselves apart.
So, just a few words from experience.
(My team hasn't used chain yet, but we plan to this year, after talking to other local team, they prefer chain over any other type of drive)

[Dan 550]

*Note*: Chains slip just as easily as belts do. Trust me, we had a kid on the team who just had a knack for breaking things. I know you all do too. Chains are a lot more annoying to reset than belts too, and you can get a nice pair of double sided serpentine belt systems with pulleys of various sizes and tensioners for around two hundred dollars, if you know where to look. See JEGS.com or NAPA Auto Stores or go to your nearest auto parts store for more on this subject.

*NOTE*: Regular old toothed gears are a thing of the past. There's a reason that they haven't been used to drive camshafts on car engines since 1935. They get too hot! The friction between two toothed gears with no liquid coolants is immense, enough to melt brass, warp aluminum, and redden steel. If you can cool it, do it. If not, wear gloves.

*NOTE*: V-belts work exceptionally well in a drivetrain, and are a lot cheaper than serpentine belt systems. Use them to change gearing. It's wonderous. A few nice CVT's use V-type belt systems. Audi's comes to mind, as well as GM's and Honda's.

*NOTE*: End of notes.