Thats right, a chain-less drive train for an off season project. Any ideas?:rolleyes:
What do you mean impossible?
Why? Have you considered using timing belt? (See 125 in 2008 if I recall)
I believe you may be referring to a belt-driven drive train. Many teams have done this in the past. As long as the belts are properly tensioned, they can work as well as chain, with much less weight.
Hereis a white paper on the topic.
Hereis one of many threads discussing this.
Good Luck,
Ethan
Our team is attempting to achieve this over the summer, well at least we are thinking about trying to try it…
I’m not really sure how we would do this though because I’m not on mechincal, but I’m hoping we succeed. Our chains broke in our final matches in Atlanta.
Impossible? I mean, I know AndyMark sells lots of stuff, but I didn’t know they sold the Impossible as well!
In all seriousness, I think the Aztecs (157) did a timing belt drive in 2005. They may have continued doing them, but I haven’t been to a regional with them since. Cyber Blue (234) did a great bit of research on belts vs. chains that you can find on CD-Media.
Hope that helps!
Team 51 used a chainless drive this year. It was 4WD and each wheel was gear driven by its own motor. The motor/gear/wheel assembly was made as a module and could bolt on to any corner of the robot.
Better not tell Raider Robotix (team 25) its impossible; they’ve been doing it since 2003.
see also: 703, 1369, 103
May I ask why?
well i always did think that mechanum wheels were somewhat witch-craft…most of them are direct driven off a gearbox…no chains
Ours also had no chain, but that’s easy with belts.
how about using shafts and bevel gears
Bruce
1517 was a belt drive this year, mecunams normally don’t use chain as BEEKMAN said, I think 126 had a belt drive in 2008, and pretty much it is not that hard to have a chainless drive.
What type of drive are you guys considering? It does sound like a neat project to use something you haven’t done before, I guess that is why they call it off-season, belt, direct drive, sprockets, other?****
We used timing belt this year to great success. I still have to question why you are so adverse to chain. Properly set up, you should never break a chain. Maybe instead of finding an entire new way of transmitting power you should look at improving your current chain setup and figure out why it didnt work. If something was wrong in the chain setup, you will surely have the same issues with belt or direct drive as those really require even more precision and thought.
Can you or someone else on your team elaborate on this a little bit more? I’m curious to how you actually broke chain, we’ve done some interesting (dumb) stuff with both 25 and #35 chain and have never actually broken the chain.
Usually, when teams have problems with chains it’s because of implementation and not the actual chain itself. Proper alignment and tension have solved any issue that I’ve ever had with chains.
But, on the original topic, having a drive train that doesn’t use chains is uncommon but not impossible. Personally, I’m biased towards the 25 method of building drive trains around gears, and I think I may experiment with this a bit in the off season. On thing you may want to consider about moving away from chains is that you’ll need increased precision in your implementation to use just about anything else. I’ve found that #35 chain is pretty forgiving to loose tolerances, but gears and belts aren’t…
If your “chains broke” in several matches, going chainless (unless you only have four wheels, each direct driven) via gears/belts will only make the problem worse. Gear and belts need higher tolerances than [35-pitch] roller chain does.
If your chains broke, it’s probably because they were improperly tensioned or misaligned. Look at solving these problems before you write off chain and attempt something else. If you don’t solve the root causes behind your chain failures, the same issues will affect whatever other drive train design you implement.
Team 103, which I am proudly a part of, has beed using relatively the same drive train, which is completely gear driven, since 2007. We were inspired by our long-time friends, 25, and built a whole now drivetrain as an offseason project after the 2006 competition. We were also sick of the problems with chain and decided to revamp our design. We have had no serious problems with our drivetrain since then. Our system has been nearly flawless, and has proved us very well. This year we are planning to make a few modifications to lower the weight, but otherwise, a very solid drive train.
We modified our system in 2008 and 2009 to deal with restrictions and increase speed.
I am confident to say that we have one of the most powerful, allong with one of the fastest tank-style drivetrains in the FRC behind a few powerhouse teams.
If you have any specific questions, please pm me.
Direct drive, good power, but drains batteries like crazy and if the drive shaft gets bent your in trouble.
We did no chain last year and loved it!!
http://www.vandenrobotics.com/ploggerb3/?level=picture&id=1517
Those were Toughbox modules we made by adding a 1/2" hole in the corner of the toughbox for a dead shaft. Then mounted a gear directly on the wheel that meshed with a gear on the output shaft of the toughbox. Then used a pillowblock bearing on the opposite side of the wheel. This is a pretty straight forward direct gearing design, that most any team could do. Down side is using a gearbox for each wheel.
This year we tried belts, but didn’t use the right size and couldn’t get the tension right, so we reverted back to #35 chain. The most common way chain comes off is misalignment and/or lack of correct tensioning.
I thought that team 25 had at one time an all gear driven drive that was modular. It was very heavy but it was very effective. I could be wrong but it has been a year our two.
These words need to be emphasized; too often inexperienced teams are unable to identify this problem on their own.
This year and last we’ve used Andymark Toughboxes (nano this year) direct-drive to the wheels. The Toughboxes stood up to the banging up and down the bumps this year with cantilevered wheels and NO signs of wear, though we only did 1 competition. It’s slightly heavier than a typical drive train, but we really liked the idea of 4 direct-driven wheels when dealing with the bumps.