OMG(osh)!!!! I built this gearset!! Here are my settings: S1-Ring 80 teeth, S1Sun=20, S1-Planet=30, S2-Sun=20, S2-Planet=28, S2-Ring=76. This gearset has a 285:1 GEAR RATIO!!!!!! This is mind blowing. I think its like a combination of a traditional planetary gearbox, combined with a harmonic drive (which are known for their high gear ratios). In this gearset, the planetary gear ratio is 5:1 (S/(S+R) and the harmonic gear ratio is 57:1 (S2R/(S2R-S1R*S2P/S1P). This is really crazy. Love, Love, Love!! this gearbox design.
I use FreeCAD and Blender, and they're both pretty lightweight to run. The need for a better computer really only comes when you start making massive and complex things. As a design gets more complex in FreeCAD it'll take longer to compute the updates - and a faster CPU will help. In Blender, as you get more sophisticated, increase the output quality, add more detailed textures and render at a higher resolution, it'll put your graphics card to work. I upgraded my GPU from a GTX960 to an RTX2070 Super and it cut the time to render video sequences in half. At a minimum, if it has an operating system and boots up and was manufactured in the last 15 years, there's a good chance it can run FreeCAD and at least an older version of Blender. I have a few old Core2 Duo computers I built in 2007 that still run and they'll happily run FreeCAD and Blender. It'll just take a few decades to render anything in HD! www.blender.org/download/requirements/ forum.freecad.org/viewtopic.php?t=16701
Thanks for the vid, I appreciate it! I want to point out that if your stack identical gearsets you will still get reduction. Make your ring gear a single, fixed "tube," and connect your 1st stage planets to the input of the second stage. I stacked two 4:1 planetary gears to get a 16:1 reduction
Brilliant! I am new to this and even bought my first 3D printer. Do you recommend printing the ring gear as is and cut it after it prints, or design a cut or notch in FreeCAD? (Which I don't know if it even is possible) Thanks or the tutorial mate! I learnt a rather lot from it!
I'd put in the notch in FreeCAD and then 3D print with the notch. Lately, I'm doing regular spur gears (not helical) so the gears all slide together easily. For a helical gearset, I'd make the notch either by subtracting a thin cube in the Part workbench, or pocketing a thing rectangle in the Part Design workbench. Congrats on your new printer!!
Thank you for posting this! super intresting. BTW check out the spreadsheet in freecad! it would allow you to make the calculations straight there, and use de results directly in the 3D geometry
Thank you. You're definitely right about that. It would have saved me a lot of tweaking numbers when I changed the tooth counts half way through. Whole thing could have just updated itself if I used the spreadsheet in FreeCAD.
I'm completely new to planetary gears (and pretty new to 3D printing) so I have some amateur questions. Should the two sun gears be attached or should they rotate independently from each other? Similar question for the planet gear pairs - joined or independent? Wrto printing, in the video you briefly mention only in passing that there are some 3D print adjustments that one might want to make to the gear teeth but I can't figure out what those might be.
Thank you very much for the video :) now, I know that the compound planets are printed with both layers unified, and the rings are printed separately. However: the suns, are the unified together, or printed separately?
In my case, I printed all of them separately, and there's a gap on the ring gear to allow it to "open up" like the letter 'c' so I can squeeze all the gears in. If you were going to print a double-helix planetary gearset without the notch, you'd have to print sun, planets, and ring all at once. There'd be no way to get the sun into the planets if the ring is solid all the way around. If the gears are just spur gears, you can easily slide them into each other so it doesn't matter if you print the set in place or some pieces separately. Once you double-helix the gears, the won't assemble without opening up the ring.
@@WhitmanTechnological yes... thank you! I have more experience from printing the “modular toy robot arm” from thingiverse, which uses many “print-in-place” compound planetary gears... but the suns are solidly printed together... There is no tooth slippage in the sun, I am amazed at that 😬
Why did you not use 'internal gear' on the ring gear? I have the feeling this was the option you were looking for at min 16. It took me a good afternoon to come to the same realisation. The internal gear option only exists in Part Design, but not in Part. FreeCAD likes to make simple things complicated because it is the way they have always done it :)
I'm using the Gears Workbench, which makes herringbone gears and other types of gears really easy, but it doesn't have an internal gear option to the best of my knowledge. I used the Involute Gear option in the Part Design Workbench for a long time until I took a serious look at the Gears Workbench. I hopped into FreeCAD to test the External Gear: True/False setting just now to see what it does. The math/geometry behind involute gears is fascinating, but I'm no expert. The profile does look like something that might be "the correct way" to build a ring gear. It certainly looks markedly different from the external gear shape. Do you think that the internal flavor of involute gear is the most correct way to construct the ring gear? I could see how that profile might eliminate problems with tooth meshing if tooth meshing is an issue. If someone wanted to use the involute gear from Part Design to make their herringbone ring gears, they could do an additive helix twice (one clockwise and one counterclockwise) and then subtract those from a cylinder, or do a subtractive helix from a cylinder. Just FYI for anyone reading these comments and looking to take a crack at it themselves.
@@WhitmanTechnological I'm just a curious hobbyist, so I can't say anything about the proper way to CAD :) However, the larger the diameter, the more triangular the gear teeth become, so I suspect it is less of an issue the larger the internal gearing becomes. I just made a 70mm outer diameter ring in my 3D printer and it works fine. Modulus 1,6, 40-20-10 teeth. 0,1mm backlash on sun and planets. I had to go to 0,05mm on the ring because the CAD broke. So there should be 0,2mm play between planet and sun, and 0,15mm play between planet and ring, to allow for heat extention. With these parameters, the gear spins freely. I'm new to printing moving parts, but in my previous designs I took 0,2mm play, so I was a little fearful the friction would be too much. However, the gear is a little too loose (I have to run it flat on the table, to not let the gears fall out). I might try a little less play in my next attempt. Changing the pressure angle from 20° to a higher number might help too.
@@JasonRobards2 Those numbers parallel my results, too. In the Gears workbench, the backlash seems to have a larger effect than I expected. Setting a backlash of 10 or 20 micrometers is enough to have a significant visible impact on the tooth profiles. With those tiny numbers, I'd have expected a much smaller effect. Next time I'm using a planetary gear set, I'll try it with the internal tooth profile for the rings. I bet it ends up working a lot better. 😊
I took a look at the Wolfrom patent. It's pretty cool. In the Wolfrom patent, the gear set has at least one extra stage (three or more stages) to allow for changing the gear ratio during operation. In the Wolfrom, you can slide an external gear along the various stages to fix (ground) different rings. So it's not just a gearbox, but a variable speed transmission. Assuming the Stage 1 ring is the output of a Wolfrom gearset. You have a sliding lock that meshes with the outside of the ring of stage 2 for the first gear ratio, and then slide that lock onto ring 3 to have a different ratio, and then slide the lock further to ring 4 to get a still different ratio, etc. It's a variable transmission with relatively few parts. Awesome. Structurally, the Wolfrom starts as the same kind of gears I made in this video, but has extra stages and the ability to ground different stages to change ratio.
You could have the ring gear on the second stage link into the sun gear on a third stage. Hold the third stage ring fixed with the first stage ring, and your output would be on the 4th stage ring. But you can get gear ratios like 300:1 from just two stages if you choose the numbers of teeth appropriately. I used multiples of four (since I have four planets) for all the tooth counts so that the planets are identical. If you use multiples of two for tooth counts, you'll need two kinds of planets (and they'll have to be aligned carefully when the gearbox is assembled). If you use arbitrary numbers of teeth, each planet might have to be different, and every planet, sun and ring will need to be oriented properly when the gearbox is assembled. It makes the planets and assembly harder, but you can get astronomical gear ratios from just a two-stage assembly if you can tolerate the extra complexity.
A younger me would have jumped at that. I've always loved helicopters. I'm mired in the robot project that most of my other videos are about and won't have time to make a video to do it justice, sorry. The swashplate is a pretty cool piece of hardware. Sleeved onto the rotor so it can slide up and down, and then ball jointed from the sleeve so it can pivot. A lower plate connects to an upper plate with a bearing to allow the top to rotate while the bottom is fixed and both plates describe the same plane. Upper plate has four ball joints that link to the leading edges of the rotors. Lower plate has two or four linkages on ball joints that connect to servos or cables to control the whole thing. An amazing design, and pretty incredible to see the rotors changing their pitch so heavily during a single rotation. I read the FAA Rotorcraft Flying Handbook once, and the part about the flex from flapping and feathering - where the rotors are curving up and down dramatically as they transition from the heavy-load-into-the-wind half of their rotation to the unloaded-away-from-the-direction-of-travel half of their rotation was something I hadn't really thought about before. Amazing those things can fly so smoothly at over a hundred knots considering the wild change in forces on the individual components over the span of a single rotation.
@@WhitmanTechnological sir it’ll be slow and steady you can create something like a course where people pay to learn all this complex design you’re good and I think it won’t take you long time to do because of your experience please think about it sir
I guess I'm confused. Which gear are you driving, which is fixed, and which is the output? Normally with a planetary system, you would have a carrier which would be your output, and your ring would be fixed. In this arrangement I'm wondering if you are driving one sun gear, fixing the other sun gear, and the ring gears are attached to each other, and they are the output??
Hey Randy, one sun is driven, one ring is fixed, and the second ring is the output. There are no carriers because the planets of one stage are made to exactly match the position and rotation of the planets on the second stage. The second stage sun is allowed to spin freely (and could be omitted but it helps to keep the planets aligned). Check it out in action on one of my other videos: ruclips.net/video/PF528b9jf0Y/видео.html The drill drives the sun and I can hold either ring and the second ring spins slowly.
@@WhitmanTechnological OK, What I think what I need to clarify, is that it seems that the two sets of planetary gears are actually attached to each other and printed as one part. Is that correct? And that is what transfers the rotation from the first stage to the second stage. I only picked this up by noticing the timelapse print at 0:25 of the video.
@@randysonnicksen9475 Exactly. Both stages of planet are printed as a single part and are therefore locked together. Stage 1 and Stage 2 have slightly different tooth counts, which produces the reducing effect of the gearbox. Driving either sun will rotate the planet pairs. The slightly different tooth counts from ring1 to ring2 causes them rotate at different speeds. Fix one ring, and you'll have a huge reduction output on the second ring compared to the rotating input on the driven sun gear.
@@WhitmanTechnological Thanks for your replies. Cool gearbox. And I was wondering how you assembled a double helix planetary gearset, until I saw the split in your ring gear. Obviously, in a "real" application that split would need to be reinforced to prevent it from opening, or shifting.
@@randysonnicksen9475 The helical ring gears are collars and slide into pockets in whatever is being driven. The pocket holds the ring closed and the nubs on the outside of the rings fit into slots in the outer part. If you want to see more, the RUclips channel "Gear Down for What" does a lot of very impressive stuff with compound planetary gears. That was my starting point for trying to build this kind of gearset in the first place.
Thank you for this information. If the output shaft required to have same speed. The sun and planet must be same size, same teeth.
OMG(osh)!!!! I built this gearset!! Here are my settings: S1-Ring 80 teeth, S1Sun=20, S1-Planet=30, S2-Sun=20, S2-Planet=28, S2-Ring=76.
This gearset has a 285:1 GEAR RATIO!!!!!! This is mind blowing. I think its like a combination of a traditional planetary gearbox, combined with a harmonic drive (which are known for their high gear ratios). In this gearset, the planetary gear ratio is 5:1 (S/(S+R) and the harmonic gear ratio is 57:1 (S2R/(S2R-S1R*S2P/S1P). This is really crazy. Love, Love, Love!! this gearbox design.
AWESOME!!!!1!!1 Congrats! Crazy how much reduction packed into a small space and with relatively few losses.
Thanks so much for the help, showed me in 1 video what woulda took me days to learn. Again thank you for the in depth teachings
What's the specifications of PC needed if I need to download 3d softwares:
Freecad,spaceclaim,blender,cinema4d
Thanks
I use FreeCAD and Blender, and they're both pretty lightweight to run. The need for a better computer really only comes when you start making massive and complex things. As a design gets more complex in FreeCAD it'll take longer to compute the updates - and a faster CPU will help. In Blender, as you get more sophisticated, increase the output quality, add more detailed textures and render at a higher resolution, it'll put your graphics card to work. I upgraded my GPU from a GTX960 to an RTX2070 Super and it cut the time to render video sequences in half.
At a minimum, if it has an operating system and boots up and was manufactured in the last 15 years, there's a good chance it can run FreeCAD and at least an older version of Blender. I have a few old Core2 Duo computers I built in 2007 that still run and they'll happily run FreeCAD and Blender. It'll just take a few decades to render anything in HD!
www.blender.org/download/requirements/
forum.freecad.org/viewtopic.php?t=16701
Thanks for the vid, I appreciate it! I want to point out that if your stack identical gearsets you will still get reduction. Make your ring gear a single, fixed "tube," and connect your 1st stage planets to the input of the second stage. I stacked two 4:1 planetary gears to get a 16:1 reduction
Interesting. How do you connect them? With a carrier on the first stage planets that drives the sun on the second stage?
Brilliant! I am new to this and even bought my first 3D printer. Do you recommend printing the ring gear as is and cut it after it prints, or design a cut or notch in FreeCAD? (Which I don't know if it even is possible) Thanks or the tutorial mate! I learnt a rather lot from it!
I'd put in the notch in FreeCAD and then 3D print with the notch. Lately, I'm doing regular spur gears (not helical) so the gears all slide together easily. For a helical gearset, I'd make the notch either by subtracting a thin cube in the Part workbench, or pocketing a thing rectangle in the Part Design workbench. Congrats on your new printer!!
@@WhitmanTechnological Tally ho mate! Much obliged good sir!
Helped me a lot thank you !
Thank you for posting this! super intresting. BTW check out the spreadsheet in freecad! it would allow you to make the calculations straight there, and use de results directly in the 3D geometry
Thank you. You're definitely right about that. It would have saved me a lot of tweaking numbers when I changed the tooth counts half way through. Whole thing could have just updated itself if I used the spreadsheet in FreeCAD.
Alt + Enter for a new line inside a cell. Great video thanks.
Thanks for the pro tip!
Useful, interesting, well done. Thanks!
I'm completely new to planetary gears (and pretty new to 3D printing) so I have some amateur questions. Should the two sun gears be attached or should they rotate independently from each other? Similar question for the planet gear pairs - joined or independent? Wrto printing, in the video you briefly mention only in passing that there are some 3D print adjustments that one might want to make to the gear teeth but I can't figure out what those might be.
Amazing 👏
Excellent tutorial
Thank you very much for the video :) now, I know that the compound planets are printed with both layers unified, and the rings are printed separately. However: the suns, are the unified together, or printed separately?
In my case, I printed all of them separately, and there's a gap on the ring gear to allow it to "open up" like the letter 'c' so I can squeeze all the gears in. If you were going to print a double-helix planetary gearset without the notch, you'd have to print sun, planets, and ring all at once. There'd be no way to get the sun into the planets if the ring is solid all the way around. If the gears are just spur gears, you can easily slide them into each other so it doesn't matter if you print the set in place or some pieces separately. Once you double-helix the gears, the won't assemble without opening up the ring.
@@WhitmanTechnological yes... thank you! I have more experience from printing the “modular toy robot arm” from thingiverse, which uses many “print-in-place” compound planetary gears... but the suns are solidly printed together... There is no tooth slippage in the sun, I am amazed at that 😬
Thanks! Really appreciate it!
Thanks for the request. :)
Why did you not use 'internal gear' on the ring gear? I have the feeling this was the option you were looking for at min 16. It took me a good afternoon to come to the same realisation. The internal gear option only exists in Part Design, but not in Part.
FreeCAD likes to make simple things complicated because it is the way they have always done it :)
I'm using the Gears Workbench, which makes herringbone gears and other types of gears really easy, but it doesn't have an internal gear option to the best of my knowledge. I used the Involute Gear option in the Part Design Workbench for a long time until I took a serious look at the Gears Workbench.
I hopped into FreeCAD to test the External Gear: True/False setting just now to see what it does. The math/geometry behind involute gears is fascinating, but I'm no expert. The profile does look like something that might be "the correct way" to build a ring gear. It certainly looks markedly different from the external gear shape.
Do you think that the internal flavor of involute gear is the most correct way to construct the ring gear? I could see how that profile might eliminate problems with tooth meshing if tooth meshing is an issue.
If someone wanted to use the involute gear from Part Design to make their herringbone ring gears, they could do an additive helix twice (one clockwise and one counterclockwise) and then subtract those from a cylinder, or do a subtractive helix from a cylinder. Just FYI for anyone reading these comments and looking to take a crack at it themselves.
I found a forum post about it and added a note to this video's description. Thanks for teaching me something new!
@@WhitmanTechnological I'm just a curious hobbyist, so I can't say anything about the proper way to CAD :) However, the larger the diameter, the more triangular the gear teeth become, so I suspect it is less of an issue the larger the internal gearing becomes.
I just made a 70mm outer diameter ring in my 3D printer and it works fine. Modulus 1,6, 40-20-10 teeth. 0,1mm backlash on sun and planets. I had to go to 0,05mm on the ring because the CAD broke. So there should be 0,2mm play between planet and sun, and 0,15mm play between planet and ring, to allow for heat extention. With these parameters, the gear spins freely.
I'm new to printing moving parts, but in my previous designs I took 0,2mm play, so I was a little fearful the friction would be too much. However, the gear is a little too loose (I have to run it flat on the table, to not let the gears fall out). I might try a little less play in my next attempt.
Changing the pressure angle from 20° to a higher number might help too.
@@JasonRobards2 Those numbers parallel my results, too. In the Gears workbench, the backlash seems to have a larger effect than I expected. Setting a backlash of 10 or 20 micrometers is enough to have a significant visible impact on the tooth profiles. With those tiny numbers, I'd have expected a much smaller effect. Next time I'm using a planetary gear set, I'll try it with the internal tooth profile for the rings. I bet it ends up working a lot better. 😊
Is the Compound Planetary Gearset identical to a Wolfrom type planetary gearset?
I took a look at the Wolfrom patent. It's pretty cool. In the Wolfrom patent, the gear set has at least one extra stage (three or more stages) to allow for changing the gear ratio during operation. In the Wolfrom, you can slide an external gear along the various stages to fix (ground) different rings. So it's not just a gearbox, but a variable speed transmission. Assuming the Stage 1 ring is the output of a Wolfrom gearset. You have a sliding lock that meshes with the outside of the ring of stage 2 for the first gear ratio, and then slide that lock onto ring 3 to have a different ratio, and then slide the lock further to ring 4 to get a still different ratio, etc. It's a variable transmission with relatively few parts. Awesome.
Structurally, the Wolfrom starts as the same kind of gears I made in this video, but has extra stages and the ability to ground different stages to change ratio.
Interesting! Do you mind sharing the patent number? There seem to be many patents on Wolfrom gears 🤷♂
@@zetteltonne4772 patents.google.com/patent/EP2146112A1/en
Can this be built with more then 2 stages? Sy 3?
You could have the ring gear on the second stage link into the sun gear on a third stage. Hold the third stage ring fixed with the first stage ring, and your output would be on the 4th stage ring. But you can get gear ratios like 300:1 from just two stages if you choose the numbers of teeth appropriately. I used multiples of four (since I have four planets) for all the tooth counts so that the planets are identical. If you use multiples of two for tooth counts, you'll need two kinds of planets (and they'll have to be aligned carefully when the gearbox is assembled). If you use arbitrary numbers of teeth, each planet might have to be different, and every planet, sun and ring will need to be oriented properly when the gearbox is assembled. It makes the planets and assembly harder, but you can get astronomical gear ratios from just a two-stage assembly if you can tolerate the extra complexity.
Thank you verry good
Hello sir please can you make a complete 4 blade helicopter swashplate step by step video please 🙏🏻🙏🏻🙏🏻
A younger me would have jumped at that. I've always loved helicopters. I'm mired in the robot project that most of my other videos are about and won't have time to make a video to do it justice, sorry. The swashplate is a pretty cool piece of hardware. Sleeved onto the rotor so it can slide up and down, and then ball jointed from the sleeve so it can pivot. A lower plate connects to an upper plate with a bearing to allow the top to rotate while the bottom is fixed and both plates describe the same plane. Upper plate has four ball joints that link to the leading edges of the rotors. Lower plate has two or four linkages on ball joints that connect to servos or cables to control the whole thing. An amazing design, and pretty incredible to see the rotors changing their pitch so heavily during a single rotation.
I read the FAA Rotorcraft Flying Handbook once, and the part about the flex from flapping and feathering - where the rotors are curving up and down dramatically as they transition from the heavy-load-into-the-wind half of their rotation to the unloaded-away-from-the-direction-of-travel half of their rotation was something I hadn't really thought about before. Amazing those things can fly so smoothly at over a hundred knots considering the wild change in forces on the individual components over the span of a single rotation.
@@WhitmanTechnological sir it’ll be slow and steady you can create something like a course where people pay to learn all this complex design you’re good and I think it won’t take you long time to do because of your experience please think about it sir
I guess I'm confused. Which gear are you driving, which is fixed, and which is the output? Normally with a planetary system, you would have a carrier which would be your output, and your ring would be fixed. In this arrangement I'm wondering if you are driving one sun gear, fixing the other sun gear, and the ring gears are attached to each other, and they are the output??
Hey Randy, one sun is driven, one ring is fixed, and the second ring is the output. There are no carriers because the planets of one stage are made to exactly match the position and rotation of the planets on the second stage. The second stage sun is allowed to spin freely (and could be omitted but it helps to keep the planets aligned). Check it out in action on one of my other videos: ruclips.net/video/PF528b9jf0Y/видео.html The drill drives the sun and I can hold either ring and the second ring spins slowly.
@@WhitmanTechnological OK, What I think what I need to clarify, is that it seems that the two sets of planetary gears are actually attached to each other and printed as one part. Is that correct? And that is what transfers the rotation from the first stage to the second stage. I only picked this up by noticing the timelapse print at 0:25 of the video.
@@randysonnicksen9475 Exactly. Both stages of planet are printed as a single part and are therefore locked together. Stage 1 and Stage 2 have slightly different tooth counts, which produces the reducing effect of the gearbox. Driving either sun will rotate the planet pairs. The slightly different tooth counts from ring1 to ring2 causes them rotate at different speeds. Fix one ring, and you'll have a huge reduction output on the second ring compared to the rotating input on the driven sun gear.
@@WhitmanTechnological Thanks for your replies. Cool gearbox. And I was wondering how you assembled a double helix planetary gearset, until I saw the split in your ring gear. Obviously, in a "real" application that split would need to be reinforced to prevent it from opening, or shifting.
@@randysonnicksen9475 The helical ring gears are collars and slide into pockets in whatever is being driven. The pocket holds the ring closed and the nubs on the outside of the rings fit into slots in the outer part. If you want to see more, the RUclips channel "Gear Down for What" does a lot of very impressive stuff with compound planetary gears. That was my starting point for trying to build this kind of gearset in the first place.
Thanks.
more videos need gratuitous buns