Society of Robots - Robot Forum
Mechanics and Construction => Mechanics and Construction => Topic started by: Mad MIR on August 19, 2011, 03:44:26 AM
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Hey guys im well on my way to building a new battlebot for a local competition and hit a snag. What is the best way to mount the axles to the chassis of my robot.
If decide to use ball bearings how would i attach the bearing to my metal frame because i know bearings are not meant to be welded.
Any help is much appreciated, thank you!
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Hi,
What is the best way to mount the axles to the chassis of my robot.
If decide to use ball bearings how would i attach the bearing to my metal frame because i know bearings are not meant to be welded.
Use a Ball Bearing Holder for each.
(http://lh3.googleusercontent.com/public/639oMhw1MdEqYdJ3CEHWchESfVvzJ9ERsCsYFv8KcUFgz6KWqq0UWBBpCRpLsiBukTH2kZBp1-T7g0KEpZxd9F6t2x6RVAcLzbvB0nhDHadMRiXql_sgk8go13fOm7rtKz2JLMVVV-YOwW1opo5nJ49Q9KADr1VqfLTCwF_G)
With the right tools you can make them yourself out of a block of aluminum.
Drill out for a the bearing (tight, but not overly so), drill the piece for a tightening bolt at the top and cut through the aluminum radially, so the bolt can secure it.
Another way, when you have the hole for the bearing, is to make two thinner plates with 1..2..3 mm smaller diameter hole to go on each side and bolt them to the center piece (for retaining the bearing.
Cheap and easy, but not nearly as resilient, would be to cut a notch into the frame, cut a hose clamp in two and bolt one half to each side - then you can tighten the clamp to retain the bearing.
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hmm, the second idea seems most suitable, it wont be too hard to build and i can easily weld the assembly to the chassis.
If i had access to proper tools, like a cnc, to machine aluminum i would have chosen the first option, but sadly i dont :/... i dont have much of a budget either.
This bot however will go through a real battering, im talking hard impacts with other robots, do you think this method of mounting bearings will hold up to that?
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hmm, the second idea seems most suitable, it wont be too hard to build and i can easily weld the assembly to the chassis.
If i had access to proper tools, like a cnc, to machine aluminum i would have chosen the first option, but sadly i dont :/... i dont have much of a budget either.
This bot however will go through a real battering, im talking hard impacts with other robots, do you think this method of mounting bearings will hold up to that?
The things soeren posted above are called pillow blocks. You wouldn't have to get it CNCed, they're readily for sale. You can even buy them with bearings already installed. Just FYI.
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Hi,
[...] do you think this method of mounting bearings will hold up to that?
I have no idea of your welding experience and that will be the crucial point (if you just make them with enough material around the bearing).
Aluminum is hard to weld. Takes a lot of heat to get the weld started and from that point, there's little play to the point where the aluminum just melts away.
There is this Aluminum solder/weld that is claimed to be stronger than the aluminum in itself. It's close to brazing in use and I'd like to try it myself, for both a robot chassis and for somewhat similar jobs, but I haven't been able to find it locally and ordering it from the US carries quite a shipping penalty :(
Personally, I wouldn't try welding such critical part in alu, but just stick it with strong bolts/nuts.
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I guess i will stick to nuts and bolts then.
Yea i heard about that stuff, 'alumiweld' i think its called.
I dont think pillow blocks are available for sale in my country, I have very limited access to pre-fab parts, what i can i order from abroad but otherwise i just try to build the parts myself.
Thank you very much soeran and corrado for your input :D