Omni Wheel

[Kilroy0846]

Our team recently purchased 6" Aluminum Omni wheels from Andy Mark. I also got the "press fit" 1/2" ID bearings that are recommended for the wheels. When they said press fit I figured heating up the wheels so the bearing would slide in, then cooling it down to get a tight fit. Contrary to my assumption, the bearings slide right in and out of the holes. I was wondering if any other teams had this problem and how you solved it. Or if there is a standard way to solve this problem that I haven't found on the forums yet :)

Thanks

[kevin.li.rit]

You can try loctite and pinning them in.

[Richard Wallace]

Are your omniwheels going to be powered; e.g., will you mount sprockets on them?

[Kilroy0846]

no they are free. They just roll on an axel

[Richard Wallace]

In that case you could try what Kevin suggested above.

Or, if you need more stability, you could mount a second bearing on the other side of the omniwheel.

The second bearing would go in a plate you would need to make or buy. The plate would need to be at least 2-1/8" in diameter and about 1/8" thick. It would need a 1-1/8" hole in the middle and a pattern of six clearance holes for 10-32 screws (about 0.2" diameter) on a 1.875" diameter circle. The plate would mount to the omniwheel using spacers, maybe 1/4" long, which would accept 10-32 screws.

The two bearings will both tend to fall out if you don't support them laterally on the inner races, so you'll need some kind of axle bushing on each side. But you'd need that anyway, to keep the omniwheel from sliding along the axle. I've seen axle bushings made from 1/2" inside diameter PVC or other kinds of pipe.

[Taylor]

http://img245.imageshack.us/img245/6749/snowflakepq7.th.jpg (http://img245.imageshack.us/my.php?image=snowflakepq7.jpg)
We make an aluminum part that holds the bearing in. This goes over the lipped side, holding it to the omniwheel.

[roborat]

We just made spacers to go between the bearings and the frame on both sides.

[lynca]

Our team recently purchased 6" Aluminum Omni wheels from Andy Mark. I also got the "press fit" 1/2" ID bearings that are recommended for the wheels. When they said press fit I figured heating up the wheels so the bearing would slide in, then cooling it down to get a tight fit. Contrary to my assumption, the bearings slide right in and out of the holes. I was wondering if any other teams had this problem and how you solved it. Or if there is a standard way to solve this problem that I haven't found on the forums yet :)

Thanks

Are all AndyMark Plastic Omni wheels designed to have a loose press fit ? Or do other teams have a tighter press fit ?
Why would you not want a tight press fit similar to the Kit Wheels ?

[Xenozero]

my team is having a similar issue, we have never used the omni wheels before. We purchased 2 omni wheels and 2 22 tooth sprockets to mount on them, but the bearing just slides right out. After some of the mentors got on the phone with the supplier, they tell them that they are designed to be used in pairs with their "omni spacers" is this true ?

[Kilroy0846]

Thanks fellas

you helped out a lot.

[Jimmy Nichols]

We are using the 6" aluminum Omni's and we are getting 7/8" OD flanged bearings to keep them from Falling through.

[aksimhal]

I know this is somewhat random question for this thread, but where are about 6" omni wheels sold besides AndyMark. (They are sold out of Aluminum wheels).

Thanks,

[Lawry Goldstein]

We used AndyMark omni wheels last year, and we have AndyMark onmiwheels, performance wheels, and Gen2 Shifters this year as well as the ToughBox, all of them have bearings that easily slide in and out of their mounts.

I assume this is on purpose, bearings in industrial applications generally require an arbor press to seat, and then a bearing puller to remove, since many teams lack one if not both of these devices, such a fit is an advantage for most FIRST teams as the cost of efficiency and stability which is immeasurably and unnoticeable for most teams.

If the stability gained from a properly seated bearing is part of your design, you’re probably making most of your drivetrain yourself, so it makes sense to me.

[vivek16]

http://img245.imageshack.us/img245/6749/snowflakepq7.th.jpg (http://img245.imageshack.us/my.php?image=snowflakepq7.jpg)
We make an aluminum part that holds the bearing in. This goes over the lipped side, holding it to the omniwheel.

haha, that was pretty much our approach. Except we just used some scrap aluminum sheet and the hand mill and only had three holes. your's looks nicer though :)

-vivek

[Jonathan Norris]

I know this is somewhat random question for this thread, but where are about 6" omni wheels sold besides AndyMark. (They are sold out of Aluminum wheels).

Thanks,

Honestly I don't know of anywhere else to buy them. Most teams used to just machine them, so I think AM may be the only supplier. Are the plastic ones sold out too??