22-06-2005 21:39

sanddrag

Re: pic: Omniwheel version 2.1

Looks good. What's the diameter, how much does it weigh, what are the rollers made of, and how thick are the plates?

22-06-2005 21:57

Matt Krass

Re: pic: Omniwheel version 2.1

The rollers are either going to be Teflon or HDPE, I'm not sure yet. The diameter is 6", each plate is 1/8" and it's 1/4" thick with both plates. The rollers are 5/8" thick (diameter 5/8" obviously). The rods for the rollers are 1/8" diameter. IT's secured together by five bolts (you can see the holes in the spokes) Not sure on the weight, I haven't figured out that aspect of SolidWorks (to be entirely honest I don't know if it has a weight calculator, I figure it does, but I don't know). The bore is a 3/8" shaft with a 3/32" keyway.

22-06-2005 22:23

Alex Cormier

Re: pic: Omniwheel version 2.1

sweet looking omnis. ya see mine?

22-06-2005 22:24

lsmith243

Re: pic: Omniwheel version 2.1

That is one sexy wheel.. I'm going to suggest it for our bot next year. Great job drawing it up too! I don't have any sweet wheel-drawing skills..

22-06-2005 22:38

Arefin Bari

Re: pic: Omniwheel version 2.1

Good job with the omni wheel Matt. If you could tell us the weight of the wheel, that would be nice (yes, I know you are trying to figure it out). Are you planning on manufacturing this, possibly sell?

22-06-2005 22:46

Francis-134

Re: pic: Omniwheel version 2.1

Very nice wheel. It seems rather similar to our design, but not quite. Anyways, I was wondering how the "omni" part of the wheel is attatched to the hub.

22-06-2005 22:57

Matt Krass

Re: pic: Omniwheel version 2.1

Well, the steel rods would be sandwhiched between the two plates (they have semi circles cut in to them, you put the omni rollers and rods in the semicircles before assembling). And the rollers (Which I've decided will be polyurethane with some assistance from my sister.) will spin freely on them.

I didn't really have any plans for it, I just wanted to design an omni wheel for a while, and I had some free time tonight so I did. If anybody else wants to use the design, feel free.

22-06-2005 23:26

sanddrag

Re: pic: Omniwheel version 2.1

When it is so boring and slow on here in the summer it is funny how all of us just jump at something technical. I don't quite recall exactly what polyurethane is like (the only thing that comes to mind at the moment is the liqid stuff in a can that I applied to the top of my workbench to seal it) but are you sure it is going to spin well on the steel pins? Perhaps you would consider pressing a brass tube into the roller to let that ride on the pin. Also, there must be some sort of provision so the end of each roller doesn't rub on the plates.

Anyway, this wheel design isn't really that different from most I've seen, but it sure is welcome in these barren forums around this time of year.

22-06-2005 23:37

Matt Krass

Re: pic: Omniwheel version 2.1

Well Materials isn't my strong suit, I selected that based on recommendations from my sister, so...I honestly couldn't tell you, but she claims it should work, good enough for me.

23-06-2005 00:12

Andy Baker

Re: pic: Omniwheel version 2.1

This is a good design. It needs some improvements, but it not too many.

1. Urethane rollers are good. Wildstang uses that materials in their "bupods". I am not sure what durometer to use, but try 50a (soft), 60a, or 70a (harder).

2. The gap between the rollers and the aluminum plates does not need to be as much as you show. I suggest a 0.02" gap on either side of the roller at the most.

3. The pockets for the rollers need an inner radius, if you are going to machine this with a CNC mill. A 1/8" or 3/16" radius will work fine. When you make this inner radius, you may need to make the pocket deeper so that the roller still clears the aluminum (that was a problem in the early versions of the 6" AndyMark trick wheel this past year). Also, the outer corner needs a small radius, in order to not dig into the urethane roller.

4. 5 screws holding the two plates together is a low number. You really don't know what kinds of loads this thing will see... it will get banged from the side, and it will see many dynamic loads. I suggest doubling the number of screws and moving them out, away from the center. Also, if you use an even number of screws, you can fasten them without nuts by having every other hole be a tapped hole.

5. The bore either is designed for a driven shaft (keyway, trantorque, etc.) or a bearing (driven by a sprocket). If it is a keyed shaft, the keyway in those two plates will get stripped. If you want to drive this with a shaft your keyway will need more face width. You can do that by adding a bolted-on hub. If it is driven by a sprocket, that can be bolted on in the same manner.

This is the start of a good design, Matt. I like the simplicity of two plates. Also, I applaud your courage for posting this (and other) design. Keep up the good work!

Andy B.

23-06-2005 03:17

i_am_Doug

Re: pic: Omniwheel version 2.1

YES... THOSE ARE DARN SEXY, THEM THERE OMNIWHEELS!!!