pic: Team 3647: Off Season Teaser 1

We have gotten into a habit of doing some serious off season work; and well this year we ended up rebuilding most of the 2012 Robot, including a new drive frame and shooter assembly.

This is a gearbox I designed to replace the P60s we were using to drive the belts on the tower; 36:1 with WCP 20DP + AM 32DP gears. For use with one or two 550 type motor.

Nice work. These are very similar to the gearboxes we made to run the rollers on our robot this past year.

One note, don’t forget about the air cooling holes on the front of the motors.

Can’t wait to see it at BATB!


Looks fantastic! Def agree with IndySam, add the cutouts for the vents on the FP/RS. Also you can go thinner on the 1/4" plate.


I’ve been keeping up with your facebook page and photos. Awesome work during the offseason. Can’t wait to see the final product.

Is there another version to fit 2, 550 motors?
Not sure where the other would mount.

Also what CAD program was this designed in?
Very nice render I like the black background.

Thanks for all the nice comments!
We will be at both the Fall Classic and Batb. More photos and stuff to come.

I did add in the vents, forgot about that at first heh… :smiley:
And will be also looking at some 3/16 plate instead of the 1/4; though we may just do the 1/4 because we have lots of the stuff lying around.

I had a version of this were there was two motors on top of each other, instead of just the one centered motor mount.

This was done in SolidWorks and rendered in the built in PhotoView 360.
Thanks! I do as well. :cool:

If the motors were on top of each other, where would the standoffs go?

You’ll see some cool superlight gearboxes when we eventually clean and post Encore’s CAD. You can DEFINITELY run thinner than 1/4" plate here, 1/8" would probably be totally adequate.

Thinner = cheaper = lighter = less material removal (faster fabrication).

After just plain having less stuff, decreasing size is the best way to save weight.

I’d also recommend looking into the .25" face width 24DP plastic gears from SDP-si for the initial stage. They are DIRT cheap at ~$2, and mate great with the banebots 10T pinions (which are also cheap, and fit through the motor boss hole). All of Encore’s gearboxes had an initial plastic stage of this size.

Yeah If you could swap that out with a plastic gear it would be great.
I have used stock-drive in the past and they are a very good company.
They have a lot of CAD files for download as well to help speed things up.

One more question, it is mainly a CAD question.
Did you take advantage of configurations in Solidworks to make the different versions (1 motor setup vs 2 motors setup)?

It’s not much of a teaser if you’re telling us what it’s for! :stuck_out_tongue:

In all seriousness, that’s a very nice gearbox. I can’t wait to see the “new” 3647 bot!

Here is the two motor version:

We are probably going to run 3/16th plate instead of the 1/4 in the cad model.
The plastic gears sound like a great idea, Adam do you have any model numbers? and what kinda bores do they have?
Also are the Banebots pinions 24DP?

I have used configurations before in Solidworks; however that feature wasn’t used to do this model. Just because… i don’t have a good reason for that :smiley:

Nice, yeah configurations would be perfect for this scenario.
The Banebot Pinion gear is a 24dp I believe.


Here is a link for my wcp gear library part. You can use it to drag and drop the part into an assembly and you will be prompted to select from a list of every gear wcp has. I would give it a try if you want I use it all the time when I am playing around with gearboxes. Also comments are welcome :wink:

Cool thanks for tip on the 24DP pinion from banebots.
Oh cool I saw that earlier; might give it a try next time I do a box.

Yeah it is really great, I kinda got addicted though I had to reformat my work computer and I do some SW 2012 CAD on it during my spare time. And I tried doing another gearbox without it and got fed up with going to find the downloaded gears every time, the drag and drop is very nice. :slight_smile:

Could you have gone with plastic gears throughout the entire gearbox or would that not have the tooth strength?

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We are doing what Adam suggested and switching the first stage to the 40T plastic [delrin] gears. However the rest of the gears we are using WCP alum ones instead of plastic gears because we just can’t find/get plastic gears with the hex bores. And we do not have the tools to do so correctly.

Without one fully knowing all the equations and factors involved in gear strength, it’s REALLY hard to say, “YES!, X is strong enough”.

I feel comfortable saying the 24DP 1/4" wide gears from sdp will hold up in nearly all initial reduction applications off a 500 sized motor (I have a slight concern about fully reversed stall torque under repeated shock loading, as Encore didn’t have any systems running that) as Encore ran that setup all over.

It’s also hard to completely characterize the loading; if you know the gearbox never experiences anything near stall torque except under initial acceleration that’s a totally different loading case than repeated bang-bang high load shocks (like an arm, elevator, something getting hit, etc…). For further stages I’d recommend increasing the DP of the gears.

I feel that the FP gearbox is a GREAT resource to look at here. Those gearboxes have been proven to be absolute tanks (in terms of the gears). Numerous teams have run them as assembled, or by removing the gears and building about that. One could infer the worst case loading at each stage there by looking at the ratios, and comparing gear size off that. Maybe throw 20% margin on there to be safe.