pic: Isometric View of A 6WD module

62102b328bb874e0256c31774f9ca741_l.jpg

An isometric view of one of our drive modules. In this setup, the middle axle would be driven, and chain would drive the outer wheels from the live axle (Check out the top view for the chain path). Because our middle wheel is lowered 1/8", that will leave at least one load bearing driven wheel at all times in case of a chain failure.

This is all a maybe.

I like! A couple questions…

How thick is the outside plate?
What size chain are you going to use?
How will you tension said chain?
Are you planning to use the kitbot gearbox?

Looks very nice and solid, a good robust design.

The plate is probably going to be .20" Thick, and we’ve always had luck with 25 chain on our 'bots. As for tensioning the chain, I am currently designing a two-sprocket Idler that will clamp on to the cross-pieces between the wheels.
For right now, we are planning to use the Kit boxes… a lot of the reason for that stems from the fact that we have so many spares laying around.
Also, the wheels pictured are skyway 6", but we will probably be using something different.

Here is another Design which was drawn up by Andrew Blair. Believe it or not, it is lighter that the above one… and it looks much more evil.
http://img62.imageshack.us/img62/8065/modulepicpd7.jpg

How’re you planning on cutting the plates? Milling squares is no fun at all and will keep you busy with a file for a long, long time. I’ve never had the occasion to cut square holes on our plasma cutter, but I’m sure it’s a better alternative.

As I recall, y’all can weld things, yes? That makes arranging something like this quite a bit easier, I’d imagine.

What is the taller part between the two wheels for? I’m guessing it’ll accept a transmission, but I’m not clear how it fits in.

We’ll probably have it CNC punched… or “Lasered” :).

As for the huge outcropping, I 'm pretty sure It is just to support the kit Transmissions.

And I think we can weld, after all we’ve only had one person set themself on fire… :smiley:

Ok, We’ve revised it somewhat, combining the two together. This is designed to fit down into the kitbot frame and bolt into place. All the axles will be driven, and the sides will be made of .125" plate. We are torn between welding the standoffs to the plate or having them bolt in place, but we’ll see what happens.

http://img371.imageshack.us/img371/8862/drivenosidetp3.png
http://img405.imageshack.us/img405/8021/drivesidepu7.png

Um, maybe a stupid question here, but if you’re using the kitbot frame to place this into, why are you even bothering with the side plates. Just use the kitbot rails to mount everything to. Am I missing something obvious that this design provides that the kitbot doesn’t?

Overall, I’m confused about the whole design, but maybe that comes from my point above… The standoffs, which look quite bulky and overly complicated, look like they’ll interfere with all your chain runs.

If you’re able to laser cut the side panels, make them straight edged instead of rounded. This will allow you to put a small 1/4" bend into the top and bottom edges, providing a MUCH stiffer side panel. (Think, kit gearbox top support plate…) That way, you can remove most of those standoffs and just put a couple, well-placed hex standoffs at the corners and in the middle.

Are those custom wheels, or just custom hubs for the skyways? I guess you’re trying to make live axles, but I’m not exactly sure why… Could you please add some more detail to the description of this setup.

Sorry if this seems like I’m harping on the design. I just don’t understand why all the custom/elaborate machining is required.

Thanks,

BEN

Ben,

We have had our share of drive train issues in the past couple years, and intend to resolve them, without a huge amount of weight increase for reliability. The modules will provide the ability to quick-swap modules, damaged, inoperable or otherwise, in a very, very short amount of time. They also provide the option of live-axles, which will alleviate some of our machining headaches (Bolt circles and the like). For us, broaching is easier than fighting with many custom bolt circles. We use an elevator wheel, and in order to interface it with our drivetrain, we need a custom hub and sprockets. Live axle allows us to standardize components.

As far as the frame goes- the kitbot frame is simply an option. Ideally, we’ll weld our own out of box tubing, but should the need arise, we are capable of using the provided frame. The standoffs are just another design beef-up, and we intended to use fairly large sprockets (1.5") to begin with- so the chain run will not be affected.

As far as the lip idea goes, I like it. However, when we give the drawings to our sponsor, it’s often a courtesy, (and a time factor) to simply have them free up one machine for a few minutes to cut a part- reducing the number of operations they must complete. I do see the strength benefit possible however, and we definitely will look into it.

As a rule in the design, we were looking for ease of removal, robustness (very important), and perhaps most of all, aesthetics. But thanks for the constructive criticism, and keep it coming! It helps to have another view to make it better. All the CAD has been done by Cody thus far though… Hopefully we get done soon for his sake!

EDIT- Also, the standoffs won’t be nearly as bulky in the final product- we’re using an old version of the bolt plate, and twice the number.