I have been approached by a team at my robotics club who have asked what are some specific similarities and differences between a sprocket and chain drive train system or a meshed gear drive train. I personally believe sprocket and chain is a better choice but what are your guys’s thoughts?
High strength sprocket and chain is definitely better…with that, even when wheels are off the ground, those on the ground get powered by all the drive motors. Also, it’s just easier to make high speed or high torque drivetrains with high strength sprocket and chain. Don’t bother with the low strength, as they break very easily.
We only use high strength sprockets, however I was making the comparison between those and high strength gears for meshing
Sprockets let you move the motors around to open up more space in the middle of your drivetrain.
Sprockets let you connect two points that are not a standard hole distance apart.
Gears have less wiggle room (arm moves but motors do not) but this can be nullified with a well tensioned chain wrap.
Gears are better for compound gearing because they are more compact when compounded.
Gears also have more sizes (84 tooth max gear vs. 60 tooth max sprocket.
I like chain and sprockets for drive so that I can move my motors back.
I heard that it’s possible to get a much better gear system from chain, but it’s harder to pull off. I’m not completely sure, but i believe that chain systems are usually sided more towards speed drive trains while gears would be better for torque. I think this because if you put resistance on a chain drive, chain may begin to bundle up causing power fluctuations, causing snapping and dislodging of chain
With chain, you’ll can potentially have tension issues. I’ve read that if you use the larger sprockets and loop the chain, it wont be as problematic. Also, you may have slipping problems. To fix that, simply use spacers on your drive train. I’ve read on the forums that you can get about 90% power efficiency from well used chain.
I don’t see why would you use high tension on a drive train considering the thickness and that you usually wont need torque so high that your gears begin to skip. If you run into skipping problems(which will probably only happen during push matches) you can apply idler gears or use lock plates to pull gears together. If you use enough gears to connect both sides of the drive, your drive train should have a lower center of balance compared to the chain drive. Another thing you should consider for gears is the price(30 dollars a set). i have a feeling you would spend much more with this system. Anyhow, through research, they say that you get about an 80% power efficiency from well used gears.
Looking at other teams, The chain or gears doesn’t make or break a team in regional. i would just stick with gears(low tension) if you must or avoid shifting gear ratios altogether. After all, reliability is the most desired trait in a robot.
This is true. While I was building a bot for the classroom last year, the chain had to much tension on it and when we went to raise the lift, one side was extremely relaxed while the other was very taught. Then a chain link snapped.
Chain has its problems that have been mentioned above but there are many good things about it. YOU can save space and transfer power over longer distances. Also with chain both sprockets rotate the same way ( if they are the same orientation to the chain. This can e very useful for drives. Chain can also be used to protect motors from stripping. A team in my club stripped lots of motors, so we put a short section of chain between the motors and the wheels. After the modification, the chain would skip once or twice during rapid changes in direction preventing stripping the motors internal gears. Chain has meny great applications just like gears. IN my opinion gears are easier to make m ore complex systems with due to their more compact size.
I’m gonna have to cast my vote for chain. Although it does have its risks and disadvantages, it has always performed pretty well. None of the drive trains I’ve geared together did as well or lasted as long as the chained drives. In my opinion, chain drives are also easier to repair or modify. If you need to add a motor, all you need to do is install it and move the chain accordingly. Motors can be mounted almost anywhere as long as they are in the same plane as the driven sprockets. Two years ago, our bot had its drive motors mounted on the lift tower and it operated well.
Also: one of the only disadvantages to sprocket and chain is how the sprocket mounts to the axle. Most HS gears have circular inserts which, as I understand it, put less strain on the axle. HS sprockets don’t have these. I don’t know if it’s a HUGE problem, but I think circular inserts for sprockets would be nice to have.
That being said, I still think that chain is a better option
I like Chain. If you’re looking for a way of combating the space issue that using chain on your drivetrain causes, this is how we’re doing ours this year.
It’s fairly compact, actually. And there really isn’t a lot of slack in any of the chain we used. I would recommend doing this for your drivetrain, and standard gears for your arm.
i don’t mean to complain, but you can hardly see the chain in the picture. I would be interrupted in a picture where the chain was more clearly visible
I think the point was more to show off how the motors were mounted relative to the chain
Sorry, my teammate informed me that I’m an idiot who didn’t check the entire Imgur album.
This is a better picture, and I’d be happy to answer any questions you have. We’ve actually added an additional crossbar across the middle of the entire frame that helps with motor support, and keeping everything square. There’s an IME on the front right wheel motor, too.