3D modeling of a gear train
3D modeling of a gear train
(OP)
I'm not sure what happened, but I had posted a question here a while ago. I received an email notification that someone had responded, but I have not been able to find the response, so.......I thought I'd try again.
I am interested in modeling in 3D, a gear train. I have in my head that I'd like to build, probably out of wood, a gear train. I'm thinking 3 stages, each stage with a 5:1 ratio. The driving gear will have 40 teeth and the driven gear will have 8. The 8 tooth gear will be hard coupled to the next 40 tooth gear which will drive the next 8 tooth gear which is hard coupled to the final 40 tooth gear. The final 40 tooth gear drives the final 8 tooth gear which is hard coupled to the output shaft.
Because I'm building out of wood, I suspect these gears will be large in diameter.
I thought it might be a time saver if I modeled these gears and worked out the dimensions and created drawings (to be used as 1:1 templates) for cutting out the parts. In addition, I thought it would be great if I could build this virtual gear train, move the first driving gear and see all of the other gears move. So I have been in search of a 3D solid modeling program that will let me do this. And here's the final requirement.....the CAD program either needs to be free (since this is a hobby project) or VERY inexpensive.
I have looked at FreeCAD but I don't think that program will allow me to move the 1st gear and then see all of the other gears move (according to the constraints I enter). I have looked at SketchUP Make (which is a great program), but again, I don't think I can get the constraint based motion. Others have recommended Fusion 360 but I don't see a free version and the purchase costs I've seen are high (maybe I'm not looking on the right spot). I am not a student so an educational copy is not an option for me.
I have recently discovered OnShape and it looks like this program will give me what I need (although I have not really used it much yet). The only downside side is that OnShape is only cloud based (I believe) and all of the designs done with a free account are available to the public (which perhaps is a good thing so others may be able to look at my designs and provide guidance). I'm so used to working from a local hard drive that working exclusively from the cloud is a big change.
Any words of advise?
I am interested in modeling in 3D, a gear train. I have in my head that I'd like to build, probably out of wood, a gear train. I'm thinking 3 stages, each stage with a 5:1 ratio. The driving gear will have 40 teeth and the driven gear will have 8. The 8 tooth gear will be hard coupled to the next 40 tooth gear which will drive the next 8 tooth gear which is hard coupled to the final 40 tooth gear. The final 40 tooth gear drives the final 8 tooth gear which is hard coupled to the output shaft.
Because I'm building out of wood, I suspect these gears will be large in diameter.
I thought it might be a time saver if I modeled these gears and worked out the dimensions and created drawings (to be used as 1:1 templates) for cutting out the parts. In addition, I thought it would be great if I could build this virtual gear train, move the first driving gear and see all of the other gears move. So I have been in search of a 3D solid modeling program that will let me do this. And here's the final requirement.....the CAD program either needs to be free (since this is a hobby project) or VERY inexpensive.
I have looked at FreeCAD but I don't think that program will allow me to move the 1st gear and then see all of the other gears move (according to the constraints I enter). I have looked at SketchUP Make (which is a great program), but again, I don't think I can get the constraint based motion. Others have recommended Fusion 360 but I don't see a free version and the purchase costs I've seen are high (maybe I'm not looking on the right spot). I am not a student so an educational copy is not an option for me.
I have recently discovered OnShape and it looks like this program will give me what I need (although I have not really used it much yet). The only downside side is that OnShape is only cloud based (I believe) and all of the designs done with a free account are available to the public (which perhaps is a good thing so others may be able to look at my designs and provide guidance). I'm so used to working from a local hard drive that working exclusively from the cloud is a big change.
Any words of advise?





RE: 3D modeling of a gear train
https://en.wikipedia.org/wiki/Involute
https://en.wikipedia.org/wiki/Involute_gear
Regardless of size, anything below 10 teeth on a gear is susceptible to skipping and binding.
RE: 3D modeling of a gear train
Since I will be fabricating my own gears by hand, I may opt to simplify the tooth profile....not sure yet.
Thanks for your reply.
RE: 3D modeling of a gear train
Lots of crappy gear models with "simplified" teeth out there to copy. Some have been the source of tens of thousands of dollars in rework and warranty and customer dissatisfaction. "Simplified" gear teeth make life quite complicated.
RE: 3D modeling of a gear train
I do gear train layout on a macro level first. Usually start in 2D with circles representing pitch and outer diameter of each gear. This makes it simple to drag gears around until I find the right place. Then fatten gears up to corect thickness and depth and finally add teeth.
RE: 3D modeling of a gear train
If this is a hobby project, why not just draw it using paper and pencil / drawing implements?
Or cut it out of cardboard if you want a moving version?
3D looks great, but sometimes previous ways can be just as good and a lot quicker....
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: 3D modeling of a gear train
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: 3D modeling of a gear train
Yes, I have seen a bunch of simplified gears online. All of these are "hobby" grade gears and probably used at low speeds.
RE: 3D modeling of a gear train
RE: 3D modeling of a gear train
1. I'd like to know how to model in 3D and move parts in an assembly to see how all of the other parts move. So the modeling part of this project is to get familiar with virtual machine design. I'm sure I would use those new found skills for lots of other ideas/projects.
2. I plan to make the gears myself (to see if I can) so that's why I am not buying the gears.
3. The gears will be spread out from one another so as to not collide with the other gear shafts.
4. I'm planning on loading the gears so cardboard won't do. I considered prototyping in cardboard and might do that as a first test.
Thanks for the reply.
RE: 3D modeling of a gear train
Z
RE: 3D modeling of a gear train
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: 3D modeling of a gear train
I have taken a closer look at AutoCAD Inventor and it looks and sounds pretty good. I may try their 30-day trial.
RE: 3D modeling of a gear train
I'm thinking that it will be easier and faster to make iterative changes on the digital prototype as compared to a physical one.
RE: 3D modeling of a gear train
https://commons.wikimedia.org/wiki/Unwin%27s_Const...
RE: 3D modeling of a gear train
RE: 3D modeling of a gear train
It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.
RE: 3D modeling of a gear train
RE: 3D modeling of a gear train
John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
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RE: 3D modeling of a gear train
TheTick: Ever see a video using the unwinding string to get the arc right? I might want to try that.
JohnRBaker: The last link I placed in this thread outlines a method for approximately drawing the curves. I might try that out.
RE: 3D modeling of a gear train
https://www.youtube.com/watch?v=r96r6IJEYKo
Benefits of involute teeth:
RE: 3D modeling of a gear train
Using Blender: http://www.otvinta.com/index.html
SolveSpace: http://solvespace.com/index.pl
RE: 3D modeling of a gear train
B.E.
You are judged not by what you know, but by what you can do.
RE: 3D modeling of a gear train
Just because you're right doesn't mean he's not wrong. Sometimes you just have to let folks work on digging their own eyeballs out with a grapefruit spoon. Even when they get done they won't be able to see that it was just a waste of time.
Happy Friday.
RE: 3D modeling of a gear train
To use the 3D printer with modern, fast computer to create an arc-shaped gear tooth approximation is - well, let's be polite - strange...
To create working gear train needs some knowledge of gearing. The theoretical shape of the gear flank is just a fraction of the whole problem.
RE: 3D modeling of a gear train
A 1:15 speed increaser is damn near impossible with precision metal gears and super-precision bearings in jig-bored plates.
With hand-filed gears, or even gears made in a real gear shaper, in wood, it probably won't even move.
Mike Halloran
Pembroke Pines, FL, USA
RE: 3D modeling of a gear train
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: 3D modeling of a gear train
Mike Halloran
Pembroke Pines, FL, USA
RE: 3D modeling of a gear train
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: 3D modeling of a gear train
Mike Halloran
Pembroke Pines, FL, USA
RE: 3D modeling of a gear train
I think getting 125:1 is quite feasible with this sort of arrangement, in a single stage, but obviously the big gear will be seriously big, and the efficiency will be shocking. On the other hand you can build it with a saw and a chisel.
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: 3D modeling of a gear train
Looks to be exactly what you need from first glance.
I rather think that wood mill above is more like 1:125, not 125:1. Kind of a big difference.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: 3D modeling of a gear train
LittleInch, Yes, I am familiar with this, thanks. Matthias is reasonably famous for his gear design tool. If you look at his YouTube channel, you'll find a number of projects using wooden gears that his has made.
RE: 3D modeling of a gear train
This guy has built this absolutely stunning machine, using a band saw.
First the music show:
https://www.youtube.com/watch?v=IvUU8joBb1Q
Then have a look at his build videos:
( Somewhere in there he glues a plotted gear onto plywood and cuts it. I think he also names the software.)
https://www.youtube.com/user/wintergatan2000/video...
Amazing!
Regards,
Tomas
RE: 3D modeling of a gear train