|
|
|
![]() |
|
|||||||
|
||||||||
![]() |
|
|
Thread Tools | Rate Thread | Display Modes |
|
|
|
#1
|
||||
|
||||
|
Re: what Chain size and tensioner to use for the drivetrain
our team has only used 35 chain. we have absolutely put it to the test too, and it has never broken. our bot in 2006 outpushed every ither bot we went up against, even the ones with outback style track designs. we bent our frame causing the chain to rub the inner frame rail, the wheel, be out of alignment, and have excess slack. it never failed. we had to replace our wheel cuz the chain started to eat throuth the aluminum side plate. 35 chain is cheap insurance. use it!
|
|
#2
|
|||||
|
|||||
|
Re: what Chain size and tensioner to use for the drivetrain
25-pitch chain will work fine for drive-train applications if you can manage the manufacturing tolerance required, and save you a fair amount of weight over 35-pitch. Team 190 has always used 25-pitch roller chain, and Team 228 will be going with 25-pitch this year.
As for tensioning roller chain, Team 228 always uses an extremely simple method of using HDPE bar stock with an off-center hole. As you rotate the HDPE around the center hole, the diameter changes and works perfectly for adding tension to roller chain. Here's a photo of three applications of these simple chain tensioners from our 2007 robot: ![]() |
|
#3
|
|||||
|
|||||
|
Re: what Chain size and tensioner to use for the drivetrain
#35 chain, and might I be the first to suggest sliding motor mounts? Leave some tolerances and mill out slots so that your motor mounts and bearingplate supports can slide back and forth -- then there's no use for tensioners, and you save some extra weight. It does take a bit more thought, though. 675 used sliding motors last year and we used tensioners the year before, and all I can say is we're not going back to tensioners.
|
|
#4
|
|||
|
|||
|
Re: what Chain size and tensioner to use for the drivetrain
We'll be using #25 chain for our drive this year. We'll tension it by sliding the front and back wheels, center wheel is direct driven.
|
|
#5
|
|||||
|
|||||
|
Re: what Chain size and tensioner to use for the drivetrain
I always use #35 for drivetrains. I've found that it's much more forgiving when dealing with misalignment. If you've got the skills and resources to keep your tolerances tight, your chain properly tensioned, and a relatively short chain, #25 can work just fine. For something as mission-critical as the drivetrain, though, I prefer the security of the bigger stuff.
|
|
#6
|
|||
|
|||
|
Re: what Chain size and tensioner to use for the drivetrain
Thanks for the info, Though my gut said #35 chain, my skill set has always been electrical/programming and thus wanted to make sure. To bad we don't have a mechanic/engineer to confirm what I thought this year.
As for the tensioner I think we are going with artdutra04 idea. Alas we do not have access to a mill and this might be the best route. Thanks |
|
#7
|
|||
|
|||
|
Re: what Chain size and tensioner to use for the drivetrain
Quote:
|
|
#8
|
|||
|
|||
|
Re: what Chain size and tensioner to use for the drivetrain
the chain doesn't eat the HDPE away?
The reason I ask is because the chain ate away a good half inch into our robot when some bolts rattled loose on a pneumatic tire, causing it to expand and push the sprocket (and thus, chain) into the frame. |
|
#9
|
|||||
|
|||||
|
Re: what Chain size and tensioner to use for the drivetrain
Quote:
#35 is far more forgiving, but heavier. |
|
#10
|
|||||
|
|||||
|
Re: what Chain size and tensioner to use for the drivetrain
Not any appreciable amount over the course of a competition season.
If you use softer or lower density plastics, the roller chain will start eating away the plastic rather quickly. But the High Density property of HDPE is great to act as a low-friction surface for the roller chain, without being eaten away. On our previous robots, after four or five competitions, all we'd notice on our chain tensioners would be a two small grooves about 1/16" of an inch deep. |
|
#11
|
||||
|
||||
|
Re: what Chain size and tensioner to use for the drivetrain
Best not to go with Chain tensioner it is more friction and more work for your CIMS. Just make the chain as tight as possible and don't worry if it take you a full day to mount the wheels. It is one of the most important parts.
|
|
#12
|
|||||
|
|||||
|
Re: what Chain size and tensioner to use for the drivetrain
Quote:
Any properly designed chain tensioner will not rob your drive of any power. Every drivetrain should have some provision for tensioning chain. If you don't, it will eventually stretch enough to be too loose, even if you calculated the exact center-center distance to allow you to use a whole number of links. |
|
#13
|
||||
|
||||
|
Re: what Chain size and tensioner to use for the drivetrain
Quote:
|
|
#14
|
|||||
|
|||||
|
Re: what Chain size and tensioner to use for the drivetrain
Quote:
However, will it really exaggerate itself over the 3-9 days that I'm guessing most teams compete (that's 1-3 events)? Not that I advocate not having a tension system. I still stand by sliding motor mounts. |
|
#15
|
|||||
|
|||||
|
Re: what Chain size and tensioner to use for the drivetrain
Making the roller chain as "tight as possible" would be a larger load on the motors than a properly tensioned drive train.
|
![]() |
| Thread Tools | |
| Display Modes | Rate This Thread |
|
|
Similar Threads
|
||||
| Thread | Thread Starter | Forum | Replies | Last Post |
| pic: Kitbot Chain Tensioner 2 | Donut | Extra Discussion | 13 | 10-12-2007 15:57 |
| pic: Kitbot Chain Tensioner 1 | Donut | Extra Discussion | 6 | 21-12-2006 00:43 |
| What size breaker should I use for the RC? | Excelsior | Electrical | 4 | 18-01-2006 07:34 |
| Chain tensioner usage | Rhs953 | Kit & Additional Hardware | 3 | 10-02-2004 17:04 |
| Chain Tensioner? | Gabriel | Technical Discussion | 14 | 29-01-2004 09:16 |