The Split-Ring Compound Planetary - My Highest Reduction Yet

[@florianfesti4325]

This mechanism definitely needs a free wheeling second sun gear to prevent exactly this kind of failure. There is an argument for also needing a planet carrier to take up the side to side tilting forces on the planets.

[@peterfitzpatrick7032]

An end plate with axle-pins and brass pinions... 🤔

[@stevengose8160]

This was my thought as he was showing off the top of the design.

[@flipschwipp6572]

Or do it symmetrical, input-output-input

[@florianfesti4325]

@@flipschwipp6572 Yes, this works, but does not allow an undisturbed 360° output as you need to connect the two input ring gears somehow.

[@laharl2k]

Yeah pretty much what OP said. I saw the failure mode coming way before he even finished assembling it. Though someone sugested brass gears, i dare you fabricate 5 different gears in brass that are not straight lines like normal gears. These gears have the same manufacturing problems double heiringbone gears have. You need to cnc them tooth by tooth on a 4 axis precision cnc mill with a really fine end mill.

[@localhawk1]

"Why are harmonic drives more popular" - because they have no backlash (0,0°). If a robot wiggles, it is not good. If robot does not wiggle, it is accurate. Anyway thanks for your videos and the very interesting content each time. Best Regards

[@OmegaF77]

Bute if I want a robot worm, I need the wiggle. Wiggle Wiggle

[@jakegarrett8109]

@@OmegaF77 it's funny because my coworker designed a robotic worm that appeared on a hackaday article and the comments were golden along those lines of "sure, robotic worm, that's what it was for", haha!

[@kristoferkrus]

What differentiates harmonic drives from this gear system that would make them have any less backlash? The harmonic drive constructed here admittedly has some backlash (at 6:57): kzbin.info/www/bejne/e57ZoGaYgblgkJY

[@bj_]

Harmonic drives can have backlash. Maybe you meant they can't be back-driven? Which depending on the robot, maybe you want a degree of back-drivability

[@localhawk1]

@@bj_ backlash < 0,0°, of course microarcs are always there. back-drivability can work on higher reductions or larger assemplys (or any other) with distortion detection of the flexspline. with load cells.

[@lagynas]

I'll become patron when you start using metric as main system.

[@LeviJanssen]

I do

[@safetyinstructor]

@@LeviJanssen what are foot chooch'rs then? ;)

[@dallynsr]

lagynas Pffft. La Dee Dah. Conversions are a fact of life, no getting around it by moving decimal points. There’s this really neat technology now that makes miles equal kilometers and cent da grades equal fair-in-hights, it’s a major pain in the neck and requires you to speak out to your google assistant or fav smartphone “convert 6 millimeters to yards!” Baaaam! Get a pen and paper it’s gonna spit that badboy out with no mercy.

[@Pinz314]

Why, whats wrong withmeasuring in banana's?

[@fightfanian]

😭 wah

[@olawlor]

I'm using one of these in a robot actuator, quite impressive performance if you can stop the planets from tilting inward. I added an "idler sun" on top that helps with this. It still skips teeth before stalling the motor, but is surprisingly debris and damage tolerant, even in 3D printed PETG!

[@seppo8703]

I stumbled onto something similar few month ago, but their design was backdrivable. The paper is called "Bilateral Drive Gear-A Highly Backdrivable Reduction Gearbox for Robotic Actuators". (commented this already with a DOI link, but comment is gone, I don't think youtube likes me :)

[@lawrenceoatman4464]

Industrial robots are taught by taking their "hand" and moving them through the motions you want them to do. This backdrives the reduction gears.

[@nemernemer]

@@lawrenceoatman4464 ”hmm, yes! Let me just teach the move-set to this Kuka Titan by pushing it” I think you mean cobots :P

[@dekutree64]

The reduction on these is essentially unlimited. The formula is "one minus the ratio of the ratios". Basically, the closer the planet/ring ratio of the top half is to the planet/ring ratio of the bottom half, the higher reduction you'll get... all the way to infinity if they're perfectly matched (i.e. the output won't move at all). Another interesting thing is that if you add a planet carrier, you can drive the carrier directly and eliminate the sun gear. However it does result in very high RPM of the planet gears. Maybe ok with metal, but for 3D printed the sun engagement is usually worth its added efficiency loss.

[@pablolopez-garcia853]

Fujimoto's Bilateral Drive, indeed one of the most advanced implementations of the 3K/Wolfrom planetary. And the gear ratio was higher, around 100:1 if I recall that correctly!

[@boluwarin]

Please I'm trying to work out how to calculate reduction for this setup. Could you please point me in the right direction? A textbook maybe or a website? I've been trying to figure this out for weeks

[@josetjaw8161]

@@boluwarin do you still need it? I've just finished making spreadsheet on determining teeth configurations (teeth number, pitch diameter, and gear ratio) for this type of planetary gear train (split-ring compound)

[@josetjaw8161]

No, the reduction is certainly not unlimited. It's high, yes but not unlimited. There are some geometrical constraints

[@dekutree64]

@@josetjaw8161 True. From trial and error with my calculator, the max ratio seems to be always less than ring teeth x planet teeth.

[@HuskyMachining]

if you need a part made over the summer, just send over the CAD and I'll send the part your way.... cool vijeo btw

[@stefanpariyski3709]

I would definitely put a planet carrier, with your design the planets can move every which way they want, which puts weird stresses on all the teeth. That would be a big step forward, and I think much better results can be obtained, even with 3d printed parts.

[@AS-ug2vq]

Is 1300:1 possible with this?

[@jacobm2625]

The mechanical nerd in me says you need carrier/holder plates for the planet gears, and have bosses coming out of the ends of the gears. Very cool design, and I learned something new today, thanks for the video!!

[@Rudmin]

If you do a bit of research this gear design is credited to Ulrich Wolfrom more than a century ago. It is often referred to as a Wolfrom drive. The publication is Wolfrom, U.: Der Wirkungsgrad von Planetenrädergetrieben. Werkstattstechnik, Vol. VI, 1912

[@AlBarathur]

Your explanation at 15:00 minutes is exactly what I was going to write. Good analysis.

[@gontzi7]

Great video dude, I don't think I would never have found this type of gear if it wasn't for you. You just gained a new subscriber

[@mike_van_in]

Ditto!

[@DBear8008]

Nice to see another Iowan with a similar mind and hobby. I’m from Fairfield, about 1:45 away. Good to know a KZbinr like this is close by!

[@adamw5449]

Thank you for naming this for me as it has also rattled around in my head quite a bit. I was sure it wouldn’t be an original thought and what ya know here it is.

[@coledavidson5630]

Glad I know what this is called now. What i never understood was how the one ring can fit the extra tooth in 13:17 i also wondered how this worked out but you explained that really well

[@carlvanheezik263]

This is a very common gear reduction. Check gear down for what and you after watching some his movies you get a ton of recommendations to make them.

[@johnmcvey386]

One of the remixes of Gear-down-for-what uses a top "sun" gear that has a round hole (not D shape) so that it just floats on the motor shaft, but serves to keep all the planet gears engaged with the top ring gear. It will solve your torque issue with only one part!

[@madeintexas3d442]

Hello from a fellow Texan here. Love your videos. I wish I could design something that looks half as good as your designs in cad.

[@mica4153]

Heck yeah. you know you're getting there when PCBway sponsors!

[@TroyMackay]

Using the same gear tooth numbers in the same volume you can get yet another order of magnitude by allowing the planet tooth count to differ on each layer. The highest ratio is when the product of opposite planet and ring teeth differs by only 1 (ie. P1R2=P2R1+1). Such high ratios are of limited use, but it does give you much more flexibility when choosing other constraints.

[@ethanmye-rs]

It reminds me a lot of a differential screw, just in gear form!

[@luismorales8085]

When will we see an update on the Coilgun Project!? Those lithium batteries were insaneee.

[@beeblaine539]

I’ve had lots of success with similar split ring compound mechanisms with a cycloidal gears. Conjoining the center gear on a 2 slightly different ratiod cycloidal drives allows for far greater gear reduction in a smaller space then planetary can offer.

[@brendansimons6811]

No planet carrier? Those compound planets are trying to twist under load. A carrier would resist that and make it a lot stronger

[@pablolopez-garcia853]

The planets are indeed loaded in torsion in this GBox, but a carrier does not help in reducing that twist, in my opinion. Although there are many carrierless designs for this GBox, I agree with you: you need a carrier to support the overturning torque produced by the two tangential forces at the meshing contacts with both annular wheels. A sun gearwheel won't solve the problem: it improves radial support, but not overturning, tangential torque. The carrier solves both... but it is heavier! 🤷‍♂️

[@BrainSlugs83]

With stepper motors, it may seem like they have a low max speed, but if you slowly accelerate them you can go faster. If you're starting from a stop and you just try a high speed it will just stall because there is no momentum, but if you slowly increase the speed in code to match the momentum you can make them go much faster.

[@stefanguiton]

Great stuff! Have you thought about using herringbone gears with this system? Will help to achieve higher torque output

[@b03tz]

Have you tried pushing herringbone gears into a planetary gearsystem before? =D

[@williamforbes6919]

Oh! So that is the name for this kind of reduction! I have one of these I designed downstairs next to my Ender!

[@Rick_Cavallaro]

This was some of the finest mechanical geeking out I've seen. Subscribed!

[@Flynntastic]

Muscatine, Iowa, first time viewer. I'm definitely going to have to build one of these! Great video!

[@adamharoon6021]

Iowa! You got this

[@keithmegow9596]

Thanks for explanation. I'm reading "the great detective" by Wesley Stout. About Chrysler development of WWII SCR 584 radar pedestal that mentions high ratio compound planetary but your details helped me understand much clearer.

[@rashmikp612]

This looks pretty cool. Have you heard about Archimedes drive? The design is based on a planetary gear system but it uses friction (toothless gears aka cylinders) instead of gears. I'm not sure if you can 3d print it but you could definitely give it a shot.

[@darylcrabb8228]

Look into hydraulic torque hubs made by Fairfield Mfg Company. Used quite a lot in mobile and industrial hydraulic applications. The one I worked on used in a recycling plant, driving a large crusher/shredder. The torque hub was driven by a very small displacement Charlynn-Eaton geroler type hydraulic motor. It was a pain getting the planet gear timing set correctly

[@obe22099]

Holding my Milwaukee M12 stubby tiny little impact wrench with 160+ ft/lbs of torque like a gun while watching this.

[@dubravkohubak5387]

Gear down for what made a nice version of this few years ago. It had a secondary sun to avoid planets bending inwards.

[@GearDownForWhat]

That guy makes some cool stuff

[@TroyMackay]

Nice work. Automatic car side mirrors are another example of their application. Other layouts can include an idler gear (by dropping same number of teeth as planet gears) or even an idler cylinder to prevent the gears bending inwards. I've also done some math to fuse the idler to the driven gear which really helps distribute the force to the planets. Would like to see some efficiency measurements - I believe the limiting factor is friction of the meshing gears under output load transmitted to the input and stalling the motor.

[@pablolopez-garcia853]

Do you know who is manufacturing those mirrors...? I heard of this application and even saw a picture of one, but never managed to get the name of the manufacturer... Thanks!

[@TroyMackay]

@@pablolopez-garcia853 I probably saw the same picture. Might be less common than I thought, looking around most appear to be worm gears. Probably a case of one manufacturer avoiding patent royalties! Thought it was a good example of using a very low gear ratio for positional accuracy but not torque transmission (due to very low efficiency). Gears easily skipping could also be a protection feature where a worm gear would otherwise strip teeth.

[@pablolopez-garcia853]

@@TroyMackay Efficiency is indeed the main limitation for these devices, althought it can be substantially improved with some tricks including a sturdy carrier and optimized tooth geometry. Thanks for your useful comments!!

[@DerekWoolverton]

The two places I've seen this mechanism used before is in a patent for car mirror electric actuators where they didn't need fast actuation but needed to be able to fight forces on the mirror like wind traveling at highway speeds. The second was in the patent for a helicopter gear reduction, where they invert the mechanism and drive the two ring gears separately with two turbines so there doesn't need to be any kind of linkage between the turbines otherwise. In that case one turbine ends up operating at a slightly higher RPM than the other, but I guess this is perfectly acceptable. I believe the turbine drove the ring gear through hypoid gears for a further reduction.

[@jakbain1337]

Made a clock that uses this mechanism it was for an engineering design challenge with restricted material, had to be water jet cut and minimum tooth size this allowed for good nesting of gears etc. Was only one of two teams that was able to get a functional clock out of 70 teams. Can say I have a soft spot for this gear type!

[@pirugnappo]

I had the same idea starting from the same assumptions about the harmonic gear. but your use of asymmetrical gears is really smart. As for the gear slip an unconnected sun gear should suffice, but I believe you have already gotten there.

[@brian8687]

This design concept is called Wolfrom drive. I have been looking up for similar high Reduction ratio speed reducers on the internet and discovered things I never knew existed Example: Archimedes Drive Traction Drive Wolfrom drive harmonic drive cycloidal drive cycloidal ball planetary transmission Planetary roller screws Its almost crazy to imagine, there is nothing anyone can think of today that someone somewhere 50-100 or more years ago hasn't thought about, we just got to find the right key word. Consider "Planetary roller screws" I first sow that design concept on one of the "Tesla Bot | Actuators Team". At the time I thought it was a new thing but until recently I discovered that same design existed some decades ago. Crazy right?

[@MarcStollmeyer]

It would be really cool to compare this drive to other methods of getting the same level of gear reduction, and compare efficiency /frictional losses.

[@lawrenceoatman4464]

In the 1970s, there was a "visible V8" model engine that had a starter motor that contained a split ring planetary drive to turn the engine.

[@escain]

Great video and project! thank you. Actually, I think that the greatest benefit of harmonic drive is the extremely low back-slash provided by the pressure that the ellipse generate between the flexible gear and the static outside gear. This is much more important for robotic or CNCs (rotating table) than having to add more torque to the motor: Just remember how much imprecision a few minute-arc of back-slash is already adding to an industrial 2m robot arm.

[@sierraecho884]

Harmonic drives are used in automotive seat recliners for example. They are fantastic in that usecase, since they are really small stamped steel cheap parts.

[@MadMathMike]

Congrats on the sponsor, and great video! 👍

[@gearcheck101]

If you put a sun gear between the planet gears that doesn't interface with the shaft, on the second ring layer, it will help support the planet gears. Oh, and now you're talking about that exact thing... :P

[@johnmcvey386]

Exactly!

[@radicalphil1871]

MKS and BTT make those NEMA 17 and 23 closed loop stepper drivers for the backs of stepper motors. They're called SERVO42 and SERVO57. They're fairely cheap and work well.

[@AnOminous1]

The split planet version was also the first version I encountered. They're fairly common in winches. I'd suggest trying a version with joined suns and planets, sun as input, 2nd carrier as output, first carrier stationary. I left details in the suggestion section of your discord April 2021. It's easier to build and I'd suggest more robust as well. I can provide more design details if interested

[@skiplgoebel8450]

excellent! i am adding you to my 'youth that will shape a better future' list. keep at it(and explore quantum science while you are at it) hats off to you sir

[@kaminmiller]

Alexandre Chappel did a video where he used 3D printed herringbone gears to drive his bench vise. Apparently the shape of the gears allows for a larger surface area for the gear teeth to mesh, making them much stronger.

[@wither8]

16:52 - That's a "no load current". A stall torque is when your motor transitions from full-load (still dynamic) to stall (output shaft no movey-movey). The phrase you're looking for is "idle current draw". 17:09 - That 2 lb water bottle drew 290 mA, as you transitioned from 270 degrees, static and proceeded to decrease from there. (Which makes sense, since you've overcome the static friction and also abs(sin(270)) =1, w/r/t gravity. Which is why if you're reefing on a bolt with a ratchet and cheater bar it's always easiest around perpendicular+the amount of downwards angular momentum you can develop). Then it reverts back to an idle current of 110mA. (Which is a lot. Was the motor still drawing that much current after you removed the assembly?) Your failure analysis is spot on re: folding itself in. It's typically bad form to say you "designed it", even if you cite the Wikipedia page. Even more so when you say "of anything I've designed", implying this is the result of multiple iteration cycles of you and/or your team. If you want to see real power density, take a look at The Torque Test channel. Handheld impact hammer drills are putting out > 1,000Nm running on stock Samsung battery packs in messy environments (ever seen a contractor work in a class 100 ISO Clean Room? Yeah me neither.) The general technique is 3 stages of planetary gearsets, each stage sequentially moving slower/made out of a denser material. By the time you hit stage 3, everything is forged steel and the lost kinetic energy (those BLDCs get up to around 22k or so) is made up for by the mass. Their setup is pretty good, but not AvE good, sadly. Developing 1,000Nm of torque is impressive, but we've been able to do that for ages with diesel generators and airlines (railroads, oil rigs, etc all operated with Ingersoll compressors). The issue is those setups have literally < 5% output efficiency. It blows my mind that these *handheld drills* can drive exploratory drill string with comparatively no losses

[@dhruvbose8294]

I don't know if you're aware of skyientific's channel. He made this same gear reducer with herringbone gears without bearings and it was quite af. Great job never the less!

[@korigarim]

Very cool concept, but if I may, I would really like a post failure tear down to see the actual damage ! (But I am sure there will be a V2 😄)

[@yonggor]

I made a few of these compound planetary gear with 62:1 and 100:1 reduction. First saw them in "gear down for what" channel. they are real powerful but confusing when calculate the gear ratio. An additional sun gear is definitely needed to keep the planetary gear from curling inwards.

[@GearDownForWhat]

I like this

[@buildthis2324]

Try redesigning the gears to be double helical. Helical gears can carry more torque.

[@motopimp2006]

Helical gears do not always contribute to higher torque ceiling. They disadvantage to helical gears is that they cause non parallel/perpendicular force on the surrounding components. Helical gears require a stronger housing and provisions outside of the gear itself. While the gear itself maybe stronger do to the increased surface area for the teeth. It can cause misalignment and premature failure during over torque conditions

[@juancarlossaavedra6757]

"worst than failure is not to try " We learn more in failure than in success. Sheers from Sydney Australia ( Planet Earth)

[@thedubiouswizard]

Great video and explanation of the mechanisms. Good luck in your internship.

[@brianegendorf2023]

If you want a HUGE differential, I would design a gear that has a 3D stepped star shape pattern, there would be a small gear that has a diagonal stepping patter that goes from either edge to center or center to edge, and then it raises a level and repeats the stepping in the opposite direction, and you would design it so that it keeps raising till you hit the 180 degree mark of the gear, at which point it starts to fall back off. Lets say you have 10 steps per star arm level. That means traversing what would would normally be 1 step on your small gear actually traversed 10 steps in the same amount of rotation, and then the pattern raises a level and reverses itself with 10 steps back in the opposite direction.

[@shaerodenaizen4375]

i'm using a harmonic drive for a turntable system for a photogrammetry rig. i needed a gear ratio that would give me a number of steps around the table that was highly divisible by many other numbers, so that i would have many options for the amount of rotation between each photo. 7200 steps per rotation ended up being that number and i used a 1:36 harmonic drive reducer to give me that number. i would have gone higher, but the teeth would have been far too small. i definitely want to give this a try.

[@johnmorris1162]

If you know someone with an EDM machine, it would be fascinating to see what could be achieved with precisely cut steel gears.

[@colbyjohnson2344]

Very nice job. It looks great. I am considering making this for my axial flux motor I created. Thank you for the clear explanation of things. Can I assume you will be adding an idler gear to keep from things skipping on the next one?

[@adamharoon6021]

Great work Levi! Have you considered live-streaming some of your CAD work?

[@gerdmeel5537]

Boring and facing heads often use a similar mechanism. Mostly one or two pinions running against two internal or spur gears with one or two tooth difference. For most applications it's probably easier to use a backlash free mechanism with lower reduction and just use a bigger servo though.

[@kaptainkraken]

Twist the gears 1/tooth arc for the smoothing out of contact faces. The output sun gear can be magnetically cushioned away from the motor shaft. What about making both sides beveled and increasing the face to face compression to try to mitigate even more tooth slippage. You could build a very powerful hinge if you had a stack of thin compressed gears like that.

[@seelenquellpoe6767]

Nice. I think i just invented (or reinvented) the split ring harmonic drive just by whatching this video :D

[@thecrapadventuresofchesimo420]

Need to move that 3d printer camera to the other end of the bed (you'll be able to see the print even better

[@jtdyalEngineer]

Great video. The problem with the design is it only has one tooth fully engaged at any one time. The planetary gears should all be linked top and bottom

[@adamcook4122]

Congrats on getting sponsored!

[@fredkaak5572]

Nice! I suppose if you'd reduce the length of the arm it would be much easier to lift. In naming the weight you should name the length of the arm too. I like how you made the planetwheels longer, that must increase the strengt of it. The idea of this makes me smile. I subscribe.

[@coledavidson5630]

Split ring planetaries are so underrated 10:40 also i really want one of these now

[@wompstopm123]

you could simply put a star shaped cap connecting all of the planetary gears together on the 2nd stage that holds them at a fixed distance. doing this would also cap off the exposed planetary gears for saftety

[@SequreTech]

Nice project!

[@АртёмВорохобин]

Hello! I think, that you can place one more sun gear on the stepper shaft, with no connection. It will prevent bending the satellites inwards.

[@nostamine2567]

WWWHAAAAAAATT ?????? u saved meee WEEKS of work WEEKS .... i really cant believe this just happened 1 hour ago ... Thank u for real . And it is so basic to build and design , god . I've been building torquier planetaries but either they are too wide or too stacked up and just to see a second stage (kinda) planetary ... i mean not all heroes wear capes . Dont ever stop designing actuators . U made my fkng day :))))))

[@user2C47]

If your printer has an extra pin, you can get a plugin for Cura that will trigger a camera whenever it finishes a layer. If you don't, there's other options. For example, my printer triggers the camera by running the bed into a switch.

[@Totalis1989]

It is interesting to see the sun gear slipping as the weakest link. If you use a different number of teeth (say 60:56) then you can use 4 normal planetary gears without needing the offset between the top and bottom halves. The sun gear can then extend further, reducing the bending you saw here.

[@hermanhoijer8595]

Levi: "This system doesn't bend at all" Also Levi: "The gears bent inwards"

[@TheUniversalid]

The world of bicycling loves ratios this extreme. Allowing 20k+ rpm electric motors yet still allow 120 rpm pedal cadence.

[@first-thoughtgiver-of-will2456]

This would totally be worth a lost-pla cast with aluminum cans. Maybe with vase mode or 0 infill. Great vid thanks.

[@tobiasgerber3546]

Good work. Looking forward to see the next version.

[@thomassutrina7469]

Like the article. The planetary gears do not have a cage holding them. This was not pointed out. The only issue is that their is a torque force with the axis between the two gears with one tooth difference of the planets thus there is also a torque in each gear keeping it from typing and for the gears without a sun there is a thrust also towards the center that need a matching torque on the sun gear. I do not know if you can make a floating sun gear for the top planetary. My Atlas lathe has a 14.5 degree gear tooth pitch angle. The most common is 20 deg, however; special gear have higher angles that will be stiffer and carry more torque at the expense of higher thrust towards the axis of the gears. Which means that the ring gear needs to be beefed up. Same thing happens for cyclonic gear because the physics or geometry is the same at the line of contract angle. It will produce the same forces independent of the type. Friction drive can use the same approach. Also there is not cage, but without teeth slippage will cause a problem. So at least two sets of rollers are needed to set an even spacing. Then there needs to be a free wheeling sun for the second. Now at least one of the roller could be an elastic item such as a tube. This will reduce the tight tolerance at the cost of the peak torque.

[@valeriucasapu1558]

This is brilliant, man! Keep going.

[@turboprint3d]

ooo I like your design alot more than mine, good job.

[@TheAuxLux]

I guess fixing bending gears issue should be quite easy. You can just connect them all together on top with bearings, right?

[@clickle23]

via a common carrier?

[@crashfactory]

yeah, totally. drop a ring on top with 5x bearings that support the centers of each planet gear. easy, and will remove that failure mode. the next failure mode would be the teeth shearing off.

[@steamcastle]

or just add a top sun.

[@crashfactory]

@@steamcastle true, needs to be disconnected from the lower sun though.

[@IljaSara]

Idler gear at the center shat for the top part of the planetary gears and a carrier/cage for them all. I think that would suffice. Although I'm not an engineer.

[@nadaso8819]

I made one of these in highschool, they’re pretty cool.

[@notrelevatthis]

Insert a exta gear in the middle on top which is loose to prevent skipping. Also integrate a Ballbearing made out of airsoft bbs. I got mine up to 50Nm

[@0redthunder0]

Congratulations on the internship!

[@Lilithe]

Put small bearings at the top of each red gear, and one around the shaft that they engage with. That way they push outward always and maybe get higher weight/torque?

[@5thearth]

I believe Oskar Van Deventer (the puzzle inventor) did something like this a while back? Might want to look at his ultra-high reduction gearbox experiments.

[@octoBadger]

Nice project, very interesting! Bit chuffed - I predicted that failure mode watching the construction. I'm guessing you've thought of a simple floating, gear-shaped spacer? Retaining it might be tricky, I think it might tend to wander and pop out :p Good work!

[@mekkarmikke]

Can't wait to see this channel grow to the number of subscribers it deserves! Love how relaxed yet interesting and entertaining the content is

[@peterwasmeier9200]

I do the same like you right now. Since 3 weeks I try to print it on my sla printer, because I need a gear with no backslash at all and really small. But it is hard to print. I have chosen 3 planets instead of 5 and more teeth on the upper inner gear instead of minus one.

[@MarkWarbington]

You missed an edit around 18:30 if you're concerned about such things.

[@LeviJanssen]

Whoops, thanks, I’m trying to fix it

[@andrewcomtois6542]

Congrats on the sponser

[@thomasjensma3496]

These are also produced with hollow cylinders as gears, and they provide even greater reductions and zero backlash since there are no teeth and there is always contact. Quite sure the company calls them Archimedes drive

[@ComeToLyfe]

Looks great! Supporting the planets on the other side as others mentioned may also helpd your backlash. Interesting use case, would be for using with non stepper motors and an O-drive like system since the gear ratio would prevent cogging. You would need basically zero backlash to make a high step count motor worthwhile. Another question is, could you make the mechanism stronger by sacrificing some of the ratio for a wider tooth profile?

[@iordanbaltaliiski2882]

Nice mechanism. If these were carbon fiber gears would they be able to achieve the maximum torque?

[@AJ-Palermo]

ooh those are some really nice motors

[@davidflynn5369]

Torque and ratio are decoupled in a compound planetary. I found this when I compared a 48:1 to a 705:1 (same size) and found the torque to be about the same.

[@hamjudo]

If that is enough torque for your application, then you can use a weaker motor. When the torque is limited by the output gears, then the only way to increase the torque is to improve those output gears. The pessimist, optimist, and engineer see the same partially full glass. The engineer sees a glass that is twice as big as it needs to be, assuming no safety margin. The engineer then takes into account that the liquid is red wine and there is a white carpet. The engineer then realizes the amount of fluid isn't the issue. They are simply at the wrong kind of party. They make an excuse about a problem at work. Then leave the pessimist behind and go off to a backyard party hosted by another engineer.

[@davidflynn5369]

@@hamjudo I didn't have enough torque, he motor stalled and nothing broke. The torque was good, just not what I expected. I had to change the geometry not the ratio.

[@pablolopez-garcia853]

Torque Ratio is Speed Ratio multiplied by efficiency in a planetary. You efficiency in the 705:1 GBox must have been around 15x lower than for the 48:1. It sounds like a lot, but it is actually possible if your planet wheels were large enough, compared to the sun gearwheel...

[@davidflynn5369]

@@pablolopez-garcia853 I used to think that. It's wrong, the math is more complex than that. Look at it as a connected lever.

[@mccarterjg]

As far as this gear set goes you add more planets to a planetary gear set and the torque goes up there's a reason why cars and semi trucks use these in their automatic transmissions. I would like to see you print another sun gear to go in the center of that second planetary without a keyed input to the shaft and then see what your torque limits are. But I will agree that the backlash would be relatively unacceptable for robotics though

[@viniciusfriasaleite8016]

Congratulations for the great videos!

[@TJPDmember]

To get the same wheel torque as a car in 1st gear, you'd simply need a reduction of about 12:1 at the end of your compound planetary!! hahah Nice work