Cool Gearing: Sun to Sun Epicyclic Gearing
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- čas přidán 3. 09. 2023
- David Hartkop demonstrates an interesting 3D printed planetary gearbox: Sun-To-Sun Epycyclic gearing with Stepped Planets of Incremental Phase Offset (STSEGWSPOIPO for short... lol).
Download 3D print files and a bill of materials to make this for yourself from google drive here: drive.google.com/drive/folder...
very cool design!
Cool design! I think what this is actually called is a split ring compound planetary gearbox. Neat how multiple people came up with the same idea independently
It's definitely a kind of that. It's actually a very old design, as it turns out, the split ring, or compound ring. This one is a little different in that there is not an internal gear, just planets that go around two suns.
I would call this a carrier-driven split sun compound planetary gearbox.
This is so cool! It reminds me of a harmonic drive, with the added benefit of not needing exotic deformable parts.
Yes, like a lot of planetary gear boxes it lets you achieve a high ratio; harmonic drives are awesome because of their low part count, but hard to do with just printed plastic. The gearbox in this video is really trying to show how to make hard-to-shear gear boxes out of plastic. It puts mechanical strength where it is needed to let you use a comparatively weak material, and still be reasonably compact. You DO have to use grease ;-D
could you share the fusion 360 file as well? i would like to study how made the contraints to move the gears, it looks really nice!
Hi there, I wanted to let you know that I uploaded the fusion files for this project: drive.google.com/file/d/1O3kef-J0OegvHsAzybsqPwGzc6PpsYLA/view?usp=drive_link
The Joint that you want to drive is called, "gear carrier to body" and it is the first one in the long list of joints in the assembly. Have fun!
In answering a general question about choosing the # of teeth for planetary gearing, here is a little spreadsheet that will help you find a working combination: docs.google.com/spreadsheets/d/1XEwKdiKt8lfYlEomOAFtGzXVUjcG9FMyumV5H4kTQeo/edit?usp=sharing
Very interesting! It is a variation of split-ring compound planetary gearbox, but better in some respects. I have an application for something like this, and am interested in your thoughts: I am not as interested in small size, high torque conversion, or high speed. I am concerned with positioning accuracy, smooth operation, and lack of "stiction." Lack of backlash is important, but not a primary concern as output need only turn in one direction, not forward/reverse. I'm thinking perhaps using a split helical tooth pattern. [May need to open outer rings for assembly.]
What kinds of ratios and speeds do you need? These split gear designs are good for high gear ratio, but do have some 'bumpiness' in their operation. It is difficult to make them run smoothly; helical gears like you said are good for smooth and quiet rotation. Maybe you need a more classical type planetary gearbox?
@@michaelretzer8480 cool; I see. Do you want it to be 3D printed?
I am interested in the math of this.
You can download stuff about this project from here: drive.google.com/drive/folders/1Vd8Iz-t7SfQN67haENu9mSlcC7crgHqZ?usp=drive_link
It looks like i do NOT actually have a spreadsheet for the math of the gearbox, however. Thanks! I'll have to do that...-david
Very cool design! I 3d printed one and got it to work at about 10 nm of torque at max speed!
But i have a doubt (sorry if its dumb, i'm quite new) if the ratio is 300:1 and my nema 17 motor is rated at 0.5nm i would expect a torque of 150nm when using this gearset(in ideal conditons). If i'm getting at max 10nm out of it doesn't it mean it is 6.6% efficient? That sounds very low, where are all those losses? Is all of it friction? I'm not sure where to start researching.
While it is theoretically 300:1, this style gear box is pretty inefficient. Also lubrication makes a difference, plus running a stepper motor too fast will reduce how much torque it can produce. What a wonderful experiment; can you share a picture / video? Would love to see somebody else's version of this thing! Nice work. 😀
@davoriffic Defenetly! I was planning on sharing a short demo video, but your video is so nice that I want to try and record a proper one laying out my tests, results and doubts. It's going to be my first time recording and editing, but I hope I can have it soon!
I'm honestly a complete noob in mechanics and robotics, I'm just starting out, so I might have made wrong assumptions, lets see how it goes.
@@davoriffic Here you can find my video on your gearbox! czcams.com/video/xYHPf5mpfVg/video.html
@@arnauaguilar8329 What happened to your video link and the video? I wanted to watch it again and see if any updates?
Very Nice ! What about backlash ?
There is remarkably little backlash; feels very tight when stopped
Have you tried adding lubricant to it? Gears are not supposed to run dry against eachother and adding the right type of lube would reduce friction and wear in the system, allowing for even greater performance.
Yes I actually did use clear silicone grease; you can’t see it in the video very well but it helped a lot
Super Getriebe, Was für Kugellager wurden eingebaut. Danke für Antwort.
I used these: uxcell 6806-2RS Deep Groove Ball Bearings 30mm Inner Dia 42mm OD 7mm Bore Double Sealed Chrome Steel Z2
what material did you print it from?
I used ABS and silicone grease
@@davoriffic Thanks for the info. I am going to start printing parts tonight for one, will let you know how it goes
Can it be backdriven?
It cannot. The friction forces are way the heck too high at that 300:1 ratio. At least with plastic gears.
ok
can it pull a standard car?
You know, there's a chance it could! I'm picturing using it to turn a winch spool, and probably replacing the stepper motor with a brushless 3 phase motor like you find in a drone or race car.
Can you make a video about that please?
How heavy a car? Are you thinking it can be powered through the cigarette lighter? 12vdc... Have you ever gotten gears laser cut from steel on send-cut-send.com? Might need to look into using brass or steel gears@@MezCook
I don't have the metal gears for that. Sorry