View Full Version : Mounting an Omniwheel
So... We got omniwheels, and want to mount them. Unfortunately, we don't know what we need to mount them. The baring can just fall out. We got spacers to mount sprockets, but they don't keep it in place either. What do we need to mount them?
Dr Theta
07-02-2011, 16:40
We need a little more information. What type of omniwheels are you using, what type of drivetrain are you using (live axle or dead axle). My gut says you need a hub but we need more information to know for sure.
viperred396
07-02-2011, 16:43
We need a little more information. What type of omniwheels are you using, what type of drivetrain are you using (live axle or dead axle). My gut says you need a hub but we need more information to know for sure.
Pics would be good too
We are using a (or we want to use) four wheel drive. It is independent of the axel. It's an 8" aluminum omniwheel. In the picture on Any Mark, the baring is just sitting in the middle, but it doesn't stay. http://www.andymark.com/ProductDetails.asp?ProductCode=am%2D0431
The wheels are independent of the axel. We are using four wheel drive, 2 of them are omniwheels. http://www.andymark.com/ProductDetails.asp?ProductCode=am%2D0431.
viperred396
07-02-2011, 16:49
The wheels are independent of the axel. We are using four wheel drive, 2 of them are omniwheels. http://www.andymark.com/ProductDetails.asp?ProductCode=am%2D0431.
Are the omni's powered?
Yes, the omniwheel are powered
Dr Theta
07-02-2011, 16:55
The wheels are independent of the axel. We are using four wheel drive, 2 of them are omniwheels. http://www.andymark.com/ProductDetails.asp?ProductCode=am%2D0431.
So it is a dead axle system, I do not personally have experience with these particular wheels however it appears that the bearings are a press fit to the center, you mount the spacers and sprockets to the wheel with bolts through the mounting holes.
Yeah, the barings go into the center and they don't just slide, but they can easily be removed, like when test drove the robot before we got the sprockets, and the omniwheels came off.
Dr Theta
07-02-2011, 17:02
Did the wheel come off the bearing or did it come off the chain? Are you using spacers on your axle to ensure the wheel can't move laterally during operation?
Jimmy Nichols
07-02-2011, 17:04
We have used these before, 6 inch version. How we mounted them on a dead ale system was using flanged Bearings similar to these: 6384K348 (http://www.mcmaster.com/itm/find.ASP?tab=find&context=psrchDtlLink&fasttrack=False&searchstring=6384K348)
I would recommended purchasing these as the quickest solution.
viperred396
07-02-2011, 17:05
Yeah, the barings go into the center and they don't just slide, but they can easily be removed, like when test drove the robot before we got the sprockets, and the omniwheels came off.
If the bearings are falling off then you need longer spacers to hold them in there or you need to fabricate some screws in the wheel to told them in
So it should look like
Frame| Spacer| Bearing | Wheel | Bearing | Spacer | Frame
The spacers should be long enough so that the wheel barely moves side to side
does that answer what you were asking?
Yeah, the barings go into the center and they don't just slide, but they can easily be removed, like when test drove the robot before we got the sprockets, and the omniwheels came off.
I have a feeling that you're not using any spacers on your axles. Try cutting some PVC pipe to length to slide over your axles to keep the wheels in the same place, it'll also keep the bearings from sliding out because theres PVC pipe in the way....
Should be like this
| is sprocket
- is axle
= is spacer
|| is wheel
-==|=||==-
viperred396
07-02-2011, 17:10
Try cutting some PVC pipe to length to slide over your axles to keep the wheels in the same place, it'll also keep the bearings from sliding out because theres PVC pipe in the way....
PVC works great for this but make sure the pipe rubs against the bearings and not the omnis... we have found that some Aluminum pipes that we cut ourselves work for this due to the thinner wall then pvc
AllenGregoryIV
07-02-2011, 17:10
viperred396 is correct, spacers will probably be your quickest solution.
You can also use shaft collars to stop the wheels from traveling latterly and prevent the bearings from falling out.
The wheel fell off of the baring. No, thats how it was when it fell off. At the time, the omniwheels were not powered (we were just testing it, and intended to make it four wheel drive). And it was Frame, spacer, wheel, spacer, frame.
viperred396
07-02-2011, 17:13
The wheel fell off of the baring.
It sounds like your bearing is a little bit to small
The wheel fell off of the baring. No, thats how it was when it fell off. At the time, the omniwheels were not powered (we were just testing it, and intended to make it four wheel drive). And it was Frame, spacer, wheel, spacer, frame.
You are putting two bearings in per wheel right? (One per side)
I've never used the omni's but i'm largely sure they work like all the other AM wheels in which you put 1 bearing in on each side.
viperred396
07-02-2011, 17:18
Have You tried turning it on and off?
For risk of feeding the troll.. Please don't post unless you have some valuable insight or ability to help the discussion
ttakashima
07-02-2011, 17:26
Are you using the single or dualie(sp?) omni? If the single you need to purchase the bearing hub off andymark. If the dualie you need to use a flagged bearing on either side and still keep those spacers. You may also use the am sprocket spacers ie: pvc-bearing-wheel-spacer-sprocket-spacer-bearing-pvc for the single wheel.
The AM omniwheel shown contains only a single bearing. You'll want at least two-bearings constraining something to a shaft -- but no more than two.
In this case, since you're using a dead-axle, I'd find the appropriate bearing to fit into whatever sprocket you've got bolted onto your omniwheel. It'll probably be an R8 flanged ball bearing and is available from AndyMark as well.
The flanges on the ball bearings constrain them axially in only one direction. You'll want to use spacers or shaft collars on the side of each bearing that faces away from the wheel to constrain them axially in both directions. Be certain that the spacer or shaft collar you use contacts ONLY the inner race of the bearing or you'll experience additional frictional losses and, perhaps, binding.
Be aware that flangeless ball bearings are not constrained axially at all in this sort of arrangement and can fall "into" the wheel. If that's the case, you can add a third spacer that lives between the wheel and sprocket, but I'd recommend getting flanged bearings instead.
The Troll
07-02-2011, 17:32
Okay I'm Serious Now. Have you tried putting a 6 inch metal plate in the middle of the wheels. If cut right and wielded it will not hit the corners purtruding out. It will connect to the rotational device. When it spins it will hold it in place while still being able to move with reinforced steel to back it up. I hope that helps. Make sure it's small enough so you dont have it flopping like a fish.
Okay I'm Serious Now. Have you tried putting a 6 inch metal plate in the middle of the wheels. If cut right and wielded it will not hit the corners purtruding out. It will connect to the rotational device. When it spins it will hold it in place while still being able to move with reinforced steel to back it up. I hope that helps. Make sure it's small enough so you dont have it flopping like a fish.
A guy on my team says that that would be like trying to make a peanut butter and jelly sandwich with a laser from a satellite in space. Overcomplicated.
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