2073 is looking into WCD, feedback requested

[billbo911]

Up until now, we have mostly been a KOP drive base shop. KOP on Steroids has been our main chassis for the last few years. We are now looking into switching it up and moving to WCD.
Here is are a couple of renders of our first attempt.





I am not a CAD master by any means, this is done by one or more of our students. I am going to ask them to follow up on any/all questions and suggestions.

We had originally thought we would try to have a single drive belt contained in the frame rails, but found that a single serpentine belt needed to wrap around idler pulleys that were way smaller than the minimum recommended by Gates. So, now we plan on using one internal to, and one just inside the frame rail.

Any comments, critiques, questions, or suggestions will be greatly appreciated.

Full size images can be viewed here and here.

[nuclearnerd]

It's a really nice rendering in any case!

I have no experience with WCD, but your design seems pretty textbook - just missing the shaft collars / circlips needed to hold the wheels on to the hex shafts.

[safiq10]

From what I see it looks good. Like others have said its just missing an clip ring or shaft collars. Everything looks to be functional and it looks beautiful! Best of luck!

[TikiTech]

Howzit!

We started using WCD last year and really like the performance. So unless the game dictates otherwise we will be using it again, though possibly a hex frame 8 wheel WCD.. I posted earlier
..
A few things.. Top render has the transmission constrained on the wrong side of the drive rail.

You will be better off not using the versa blocks on the center and just drilling your center hole to use the WCD gearing block.
http://www.wcproducts.net/217-3634/

You will also need to drill a few holes on the drive rail for the bolt heads on the transmission plate to nest into. This will allow the transmission plate to rest against the drive rail giving much better support. You can run a dual sprocket on the transmission to drive each of the outer wheels.

I suggest #35 chain. We have been using #25 but last year we had to tension the chain more often due to our use of the WCD 3 CIM dual speed transmission. (great transmission by the way)

Also factor in a chain/belt cover. Nothing is worse than an electrical wire getting in there. Most of the time an encoder is mounted to one of the outer wheel shafts. Plus the judges like things to be safe!

I am sure I will think of more after I post this..

Good luck with this, looking good!
Aloha

[Michael Corsetto]

Bill,

We should arrange an in-person design review in December. It would be a great experience for both teams. We're not too far away after all

-Mike

[asid61]

Originally Posted by TikiTech

Also factor in a chain/belt cover. Nothing is worse than an electrical wire getting in there. Most of the time an encoder is mounted to one of the outer wheel shafts. Plus the judges like things to be safe!

I am sure I will think of more after I post this..

Good luck with this, looking good!
Aloha

+1. Some inspectors will not like the uncovered chain, but more importantly stuff can get snagged in there really easily.
Also, when doing renders, turn on perspective. It makes it looks a little more realistic.

[mlantry]

I'm unsure if the little tabs on the edges are for bumpers but if they are I would either come up with a way to support them or a beefier way because I could see though bending easily if a team gets under you bumpers. Aside from that looks good

[MrBasse]

Originally Posted by TikiTech

...Top render has the transmission constrained on the wrong side of the drive rail...

I saw that too, but I think that is just the wheel reflection in the frame rail.

Looks great to me, once you figure out chain/belt runs you should be set. We have had a harder time figuring out chain/belt runs than anything else building our first in house drive train.

BTW, your RSL is hanging outside your frame perimeter...

[MichaelBick]

First of all, there is no pulleys on the inside of the gearbox for the two back wheels.

In tube belts is going to be a nightmare to fix. With a regular WCD, the spacers in the gearbox make it harder to fix belts, but doable because you can always just remove the back plate. With this setup, you have to remove the entire gearbox to replace the in-tube belts.

[FrankJ]

Keeping in mind that it has the 2014 controls.... Anything under the CIMs is going to be hard to access. You would also want to make your radio platform easy to remove so you can get to PD board. Depending what ends up on top, you might want to face your pneumatic controls & gauges out. The disconnect switch looks a little buried. You obliviously have a little rearranging to do to make the belts work.

[billbo911]

Originally Posted by Michael Corsetto

Bill,

We should arrange an in-person design review in December. It would be a great experience for both teams. We're not too far away after all

-Mike

Excellent idea! I know we plan on meeting with your team leadership to discuss CCC, maybe we can coordinate both things happening at once?

Everyone else, THANKS!! Please continue the feedback!

Great observations and suggestions so far. Correcting these details will go a LONG way to make this a successful endeavor!

[JesseK]

It looks like this setup only mounts the WCP gearboxes via 2 #10 bolts. Could you or your students provide an exploded view, or a close-up view, of the gearbox, rail, intended bearings, and all bolts around one side of the bot's center wheel? Making the rail transparent or semi-transparent would also help.

[billbo911]

I'm working with the student who created this to get his CD account set up so he can respond directly to these questions. The team is out of school this week, so communications are a bit slow. I hope to have him up on the board later today.

Originally Posted by JesseK

It looks like this setup only mounts the WCP gearboxes via 2 #10 bolts. Could you or your students provide an exploded view, or a close-up view, of the gearbox, rail, intended bearings, and all bolts around one side of the bot's center wheel? Making the rail transparent or semi-transparent would also help.

Thanks for the request JesseK, we will work on getting that up ASAP.

[AustinSchuh]

Looks like you have ~1" between the bumpers and the wheels. Consider pushing your wheels out a bit further. That'll give you more room inside the base for your electronics.

Why not stand the battery upright? The bumpers will extend to the top of the battery anyways, and you gain a bunch of space back.

The 20/30 amp fuses are hard to get to and see. Move the radio up a lot, or somewhere else.

Considering that the electronics will change next year, can you get models of them and try fitting them into your base instead? That'll be more valuable (and they are smaller!)

[R.C.]

Bill,

The things I would change:

-Don't use a full versasblock per gearbox, use 1/2. And mount the gearbox so the face of the gearbox is flush.

-Use the WCD 2 CIM DS and ditch the belts inside the tube. Go to 18T sprockets and run chain, you'll be much happier. If you still want to run belts, I would read some of the posts/docs on here about tooth size and width of belts.

I would comment on the electronics layout but Austin has me beat!