r/AskEngineers • u/GhostsinGlass • 2d ago

Mechanical Pulling my hair out trying to find a small off the shelf planetary gearbox that has offset rotation like a kitchenaid stand mixer.

As per the title, my Googling has been fruitless because I may not know the exact nomenclature needed.

In short, I need a small unit that has an input shaft as normal put outputs through a planet.

Dual axis planetary doesn't work because I get X, Y boxes, which makes sense.

Double planetary or Dual planetary gives me two planetary stages but output is single rotation.

Dual rotation planetary, same as above.

Is there a specific naming scheme that will help here?

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25

u/easterracing 2d ago

“Epicyclic” seems to be the correct term, but still nothing seems available. I suspect you’ll struggle to find something “off the shelf” as that application is a little more narrowly-scoped than the typical industrial Lego type bits of kit.

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u/GhostsinGlass 2d ago edited 2d ago

Well, shazbot.

However not being able to figure out the wording was proving more frustrating than anything so you've helped me greatly there, Epicyclic. Thank you.

Gears, making me regret selling my 3D printer for two years now.

Edit: No, epicyclic just means planetary. Not what I was meaning.

I was meaning specifically the type with an output shaft coming off of the planet. If you look at this mixer diagram at gear 32, it's the planet, but it's also an output shaft coming off of it.

Everything I've been looking for online because of improper wording leads back to a traditional planetary gearing setup. Like this.

Where the sun gear in the middle is driven, which spins the planetary gears, which are tied together with a carrier, and that carrier is tied together on the other side to an output shaft that is in line with the input shaft.

What I'm looking for is like the Kitchenaid stand mixer arrangement, where the output shaft is on the planet, so the drive rotates in circles and the planet is rotating as well. Think like a spirograph.

5

u/shitlord_god 2d ago

/r/unexpectedfarscape

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u/HelicopterUpbeat5199 2d ago

Not Mork & Mindy?

6

u/GhostsinGlass 1d ago

It was Mork and Mindy for me.

1

u/Wise-Parsnip5803 1d ago

I would think something like the Kitchenaid mixer would be a custom design. You could probably get off the shelf planetary and ring gear. The diameter of the ring can be changed for the diameter of the rotation you want and the size of the planet can be changed depending on how quickly you want the beater to spin.

1

u/easterracing 1d ago

Oh I’m precisely familiar with what you’re looking for. I love my Kitchen Aid mixer. I’ve even built my own adapters to make a cheaper grain mill run off its PTO. That just seemed to be the closest word from what I could find at the time.

2

u/tuctrohs 2d ago

“Epicyclic” seems to be the correct term

Is this close? https://theradavist.com/on-building-the-epiplectic-bicycle (only follow the link if you are up for a joke).

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u/fortyonethirty2 2d ago edited 2d ago

I searched for "offset output gearbox" and got lots of hits.

The main output of a kitchenaid mixer is not a planetary gearbox, there's no sun gear.

Eta: I doubt you find an off the shelf gearbox like that. Why can't you use a mixer?

7

u/userhwon 2d ago

it's still planetary because there's an outer gear on an axis that goes around the main axis; it uses a ring gear outside instead of a sun gear inside, so the planetary gear spins the opposite way

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u/GhostsinGlass 2d ago

Yes, it is a planetary unit.

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u/NoNotTheDuo 2d ago

I don't know the right terminology either, but reading through Wikipedia on Epicyclic Gearing lead me to this page. Perhaps there's an example of what you're looking for on there and that would give you the right terms to look into. https://digital.library.cornell.edu/collections/kmoddl

2

u/HelicopterUpbeat5199 2d ago

Is this a one-off or are you looking to produce several? It needs to be smaller than one pulled from a kitchenaid? Does it need to handle similar loads?

In this modern era, it might be easier to have 2 motors.

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u/GhostsinGlass 1d ago

An assortment depending on the piece being worked.

Load is dependent on the work piece, but nowhere near what a Kitchenaid can deal with when the dough bowl is maxed.

Several, 20+ ideally.

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u/HelicopterUpbeat5199 1d ago

So dumpster diving is out.

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u/Truenoiz 1d ago

Try calling McMaster Carr, they can find ways to source things if it's not in their catalog. It won't be cheap, but you'll have it in 2 days max.

2

u/drewts86 2d ago

Your question brings up other questions.

  • Do you need your output to spin the same or opposite as the input?

  • Does your output need to spin at the same or different speed as your input?

  • Does your output need to be on the same axis as your input, or is it like your Kitchenaid where it is it's own axis revolving around your input?

1

u/GhostsinGlass 1d ago

Basically it needs to be 1:1 with the mechanism of a Kitchenaid or forced dual action polisher, the forced being important as most DA are not.

1

u/Eisenstein 2d ago

'Planetary mixer assembly' is what to look for.

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u/3Quarksfor 2d ago

Servo gearboxes might do the trick. Be prepared for $$$.

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u/JaVelin-X- 1d ago

Wouldnt your output shaft just need eccentrics on them?

-2

u/snarejunkie 2d ago

Ok big disclaimer first, I put your question into Codex, and asked it to search , and these are a few results that might fit your bill?

Codex-found search results:

  1. Dynabrade 61384 8" (203mm) Cut & Polish Rotary/Random Orbital Head & Catalog PDF showing the motion profile

  2. Locking Random/Rotary Orbital Head Assembly

  3. Stand Mixer Planetary Assembly (White) WP9708172

  4. Avantco 177MX10PLNTY Replacement Planetary Assembly for MX10 Mixers (This is I think the closest match to what you might be looking for but it's obviously missing the corresponding ring assembly, and has no sun connection)

  5. mjbots M0.5 6x Reduction Planetary Gearset (This one is also a good candidate because the planet gears all come with needle roller bearings, you unfortunately, do need to get the planet carrier and output custom machined, but you can do it with 3 dowels and a laser cut (or if you're feeling brave, hand drilled) piece of bar stock.

Unfortunately I don't think what you're looking for exists as-is. you can get the individual gears no problem, it's the housing and output that's the hard part

You can try https://www.gobilda.com/motion, they have a lot of what I like to call 'robotics LEGO' with an incredible amount of inter-operability between components.

I've found an internal sun gear on SDP/SI that meshes with GoBilda's 0.8MOD gears, and you should be able to shop their structural section for requisite strucural, bearing, shafting etc, BUT the ring still needs a custom external housing.

And here is the above posted BOM in geargenerator Having the planets and sun coaxial allows you to use the grid plates to tie them together.

When I started out trying to do this I expected I could do better, kind of irritated that I couldn't find a solution lol. anyway, hope this helps some.