Ok the end goal is to have a gearbox/wheel combo that takes less space and is customizable. it will look something like this
It is to achieve the following.
Customizable ratios - the bevels are intended to come off the motor and input shaft easily so that
can allow to quickly change ratios from 6:1 to 11:1 in minutes.
Take less space “where it counts” like often the motors sticking out interfere with ball intakes.
Hopefully provide cooling for the motor as we will attach a fan to the gear that is mounted on the motor shaft. (That is currently under discussion)
Reduce Weight - without the motor (which could be CIM, Mini CIM, NEO) The whole wheel/gearbox combo including all mounting hardware and bearings (5-10 608) will be about 2lb.
Reduce cost. Including everything (if it works as intended) will be below $ 25.
The first version will go into a demo / community outreach bot. If it works well there it might make itself into the competition bots which we hope very much.
As for 3DP we consider it a tool to build robots rather than a hobby - unless you consider doing FIRST a hobby in which case - it would be.
Everything I post is at least a co-production. At this moment we spent going over gears/gearboxes and how to draw them. The kids figured out and designed/cadded the components. I fixed some things like today I changed the backlash (and told them) cause the thing was too loose and I print as currently all printers are at my house. We are remote only due to covid. I then take pictures/videos of the stuff they designed and I printed and post it on our Discord Channel that we use to communicate/hold meetings. I also go order/pick up parts and then drop them at the kids porches/front/back door and they do a task with it like disassemble, assemble, paint, Cut something, drill holes - depending on what tools they have at home and whats ok with their parents. Then I pick stuff up and either bring it someplace else or my place and I QC everything like I used to when we were “in person” before covid. If it passes/fine - if it doesn’t and its something minor I might fix it right there or bring it back or inform the cad people to change the design.
The prototype in this post is the 2nd iteration. The first one I posted some “problem pics” on discord with
Planet carrier does not fit over bevel gear mount there is no way to assemble it
Planet carrier is too flimsy.
There is no way to get a wrench in there either make a holder for the head of the bolt (like the did as is shown in the above picture as part of the thickening of the planet holder) or find some room on that side when the bevel is in place.
Then I got the above version and printed it and I put it together and there is a report that we need a bearing holder for the sun on the outside ring gear holder and the mount for the bevel on the outside (not shown) needs to be redesigned. So the whole thing has been going on for a couple of weeks now but now we actually have something to hold and look at (and take pics)
Now someone will redo the outside holder. I changed the backlash right now and refreshed the drawing cause I consider that minor I might have to change the backlash a couple of more times in different places until its neither too loose nor too tight. This is what happens with 3DP gear system at least the printers are quite consistent so once a part is “dialed in” you can print many and they come out close enough. There might be some flowrate and/or backlash adjustments necessary again when we go to Nylon. The reason we are doing them in HIPS right now is cause we pick up HIPS for <$10/kg including shipping. So its not that financially painful if you got to redo a part. We are even considering making the gear boxes for the demo bot out of HIPS and see how long that lasts running it over rough terrain.
So I guess its a both. As for who does it. Its usually a both in the “in person” world too. As you got to show them how to do it at least once.
Now the Bevels atm are all me as no one knows how to do them right including me and what is the best way. I have figured straight bevels out and they work great but am still struggling in properly designing a proper zero bevel or double helical one. Would be nice to use those as they are self aligning (like the double helical gears in the planetary above) and that would make mounting/changing/replacing them easier. I am currently preparing a “class” where I will teach them how to do a proper 3DP plastic straight bevel gear and then they will design one for that gearbox in place of the one I designed. So that is how that works.
Now the community outreach bot will look something like this
octagonal, 26 in frame diameter (more with the Body) and about 5 foot tall couple of my kids are working currently on the head which will look something like this
Another 2 are working on the gearbox above, another 2 on a 30:1 for the arms which at some point might also be used in a climber another couple on the electronics , 2 on the programming and the rest misc pieces like battery holders brackets etc