Beveled Gear System With Sprockets! Share Your Thoughts

That’s very intriguing… negligible power losses… negligible slop… What could it be?

I tried to come up with any alternative to vex bevel gears or 1727Z crown gears.

This is easy to build but has lots of slop, so no.

This seemed like a good idea at first, but the pegs are slopped at the weird angle and not at sproket pitch. So not likely either.

Going back to gears, one of these may be usable, but seems like plastic gears will be wearing out fast.

gears 1

gears 2

gears 3

Finally, going without any gears or sprokets, this traction wheel design might actually work if you don’t mind it slipping at some point.

Am I any closer to your cool design @Ethan5956F?


No. The second one is neat though. If you got a spacer that matched the curve of the sprockets you could get something pretty low friction and low slop

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@Ethan5956F Maybe not your design, but a couple of these (with a 1/2" shaft connecting them) could do a 90 degree power transfer pretty effectively. (negligible power loss, negligible slop as far as I can tell)


The vex u joints have a non constant velocity transfer iirc. You’d be better off doing something like a Hobsons joint. Here’s a demonstration of a prototype I made a while back:



There’s also a vid I posted at some point floating around in vtow where Im spinning it with my hands. Can’t find it tho

(Note im not currently using any Hobson joints for any 90° transfer, as it’s inferior to most bevel designs because it relies on sliding friction rather than rolling resistance. However, the slop can be made quite low, and the friction is very smooth compared to most other models I’ve seen. If it’s tuned and supported correctly it works better than the crown gears contraptions I’ve seen so far. As I said before though, this is not the best design. There are better options. Pls don’t use a hobsons joint in vrc)

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Lol, if you search forums for any info on u-joints the first thing that comes up is about how they are literally falling apart under any usable load.

Also, Hobsons joint screams cantelievered x2 and friction^10 all at once.

I also thought about doing something like this

but figured out you would need too many custom parts cut…

Then there are rope belts, but that’s also would be something too complicated to make, at least, for my team.


That idea would have a lot of slipping going on all your previous ideas on beveled gears are very cool :ok_hand:

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There are ways to get around the friction but yes there is essentially no way to get around them being canti’d so you have to use really strong and really short rods if you want them to support any load (main reason why I wouldn’t recommend them in vrc)


Here are some more I found on “mechanisms” playlist (which is also generally a good resource for robotics.

These seem…possible…to implement in VRC, but probably with the same drawbacks as the Hobson’s Joint. Just wanted to throw some more out there.


My opinion on this is that at that point, just use crown gears


I messed around with making that type of joint thang shows too and I gotta say it’s pretty difficult to get anything worth the time working out of that in vrc. Itd be easy to make one of those in vexu with 3D printing but there’s no point cuz u can just make or buy a bevel lol


Thang is op but his ideas are too big brained for most applications we can use in vex unfortunately

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cnc’ing the metal pinions into custom bevel gears could be viable, but it requires some pretty heavy machinery, and not something most teams could easily do.


I made a few of those and it works well under load and has extremely low slop but there’s one slightly better alternative that I’m using

you’re using 90 degree energy transfer on your robot?

Not for my comp bot no. Just a side project I’m doing for fun

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Those videos are very interesting I’ve never seen joints like that. It would be very difficult to build them tho

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I would like to see your attempts at doing that or did you even do it. No proof then no trust

I don’t need your trust : )


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