How to model Gear Racks, Straight and Helical, Parametric (Gears pt 4/7)
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- Опубліковано 29 чер 2024
- In this video I show how to model a gear rack in Fusion360, though the method translates easily to any other CAD package.
Topics covered:
0:00 Introduction and setting up parameters
1:27 Sketching the tooth profile
5:08 Patterning the tooth to make a rack
6:12 Modifying rack by changing parameters
6:50 Adding backlash to the rack
7:43 Making a Helical Rack
9:08 Looking at Transverse vs Normal module
12:22 Slicing a rack in Cura
13:14 Meshing demo; joints and motion link
18:40 Conclusion
Full gears playlist: • All about gears
KHK gears drawing:
khkgears.net/new/gear_knowled...
Rack .f3d file:
www.creonova.nl/wp-content/up...
Meshing demo .f3d file:
www.creonova.nl/wp-content/up...
Website: www.creonova.nl/
Instagram: / creo_nova - Наука та технологія
You're a hidden gem of UA-cam. Pure genius and exactly what I needed for my project. Thank you for posting these!
Thanks a lot, good luck with your project!
I got to hand it to ya. I've come back to this video a lot when working on projects. The knowledge you gave with those user parameter settings are gold. For everything, not just gears. I kind of learned that the hard way last project once i had way too many fixed dimensions to make it manageable. So now, I am starting over from scratch, and the first thing I am going to do from now on with EVERY project I start is make a dimension list and then enter all those dimensions as user parameters. It's not that my fixed dimensions weren't accurate before, but only for certain models and conditions. Which of course, have a way of changing over time. With editable parameters, i don't have to start over anymore. I just change the parameters. This is going to be a staple of my workflow from now on. THANK YOU!
Incredibly useful series! I've been trying to find a spur gear generator for a while now. Who knew it was built into Fusion 360. This series as helped a lot with the 3d printer motion system I've been working on. Thank you!
Also, a useful tip for those who don't know, you can right click on a sketch and click "Show dimensions" so you can modify dimension values without having to go back into the sketch.
Awesome video as always! Your videos really are the gold standard on youtube when it comes to gears, well done!
Thanks! That's a large part of the reason I'm doing this I must say. It actually started when I found out that a lot of tutorials about gears are just wrong. They're creating the wrong shapes...
@@antalz Well keep doing the awesome work please :) I also really enjoy the flow of your videos; in-depth but straight to the point
@@TheHypaaa Thanks, and I certainly will!
one of the most useful videos i have seen for what i specifically need Thank you!
THIS IS insane!!! Why did it take me years to find somebody who can explain it simply, yet still using a "complex" method!
Thankyou very much
My pleasure, thanks for watching. That's really why I started this series.
Excellent tutorial, exactly what I was looking for. Thank you.
Hi, Awesome video! I think its the best tutorial/series about gear design I've seen on youtube! I was wondering if you 'll cover internal or inner gears in the future?
Yeah that's actually the next part. I only have an approximate method though, it's not mathematically exact unfortunately. If you're in a hurry, geardownforwhat has a tutorial on compound planetary gears that also covers at least the basic method.
This is awesome, thank you for your wisdom and knowledge
This Is Just what I needed , You are a Guru My friend! Subscribed.
Great tutorials for gears! Thank you for sharing this.
Thank you for watching, good luck!
hello Sir,i am a newbee,but i sure very much like your video's about maling and explaining how gears works,thank you
this is just perfect and comprehensive
Thank you, thanks for watching
wild because before I started watching this I was digging through my gear books. I was reading the KHK book :)
KHK publishing so much info was really a great help in making this series
brilliant. exactly what i needed! Thankyou.
Great to hear, good luck with your projects
Thank you for the great video! I found a few others but none nearly as concise and easy to follow as yours!
One note on the Cura configuration, I just draw my component sketches onto the XY plane so when I export the STL's, they then import into Cura in the correct orientation! Or model then change their position before exporting.
Thanks so much, that's pretty much why I made this series. The Cura tip does work, but I often have components that are part of a larger assembly, so their orientation is dictated by the assembly unfortunately. Doing some rotations is not a big deal though, and of course I always try to keep printability in mind when designing.
There's a video on the channel about Hobgoblin drive units, those for example were designed as an assembly, not a bunch of separate parts.
@@antalz Definitely understand your reasoning for modeling in this orientation!
As soon as I typed out my response I thought about it for a moment and figured you’re very well aware of how the orientations work! Haha
@@ThinAir-3D It's still worth while to write out your suggestions, you never know what someone else might overlook. Also don't forget tons of other people read the comments, so they can be useful to them too.
@@antalz You are absolutely right about that!
A great video you help me out again first win planetary and now with rack and pinion
Thanks, good to hear this series helps!
Awesome video!
Thank you!
Great video series! I think you can get the width parameter to work (at least in this case) if you open the spur gear component and edit the two extrudes, replacing the distance values with your parameter.
I should give that a try, but unfortunately the thickness is perhaps the least interesting parameter. You can just change it whenever by extruding the flat faces. You could even change the module by doing a scale in XY. The big blocker is the number of teeth, which obviously affects how many teeth there are, but also the shape of those teeth. That just can't be parametrized unless you sketch an involute approximation yourself. If you want to try that out, check out a small channel named "Steel Stone"
@@antalz I saw that video, pretty involved process. Another approach might be to hack the SpurGear.py script to accept an existing component, then update the 2nd sketch with the tooth profile using points generated by the new parameters. With any luck the extrudes, fillets and pattern commands that follow would still work
@@bobmvideos That might work well. Unfortunately I haven't yet checked out scripting in Fusin360, and I fear I won't for a long time to come. I'm quite busy at the moment unfortunately, even my next video on the 3D printed drybox is seriously delayed.
On your note about Cura and the orientation: if you correctly use the variable layer height you can have extremely smooth layer transition.
Variable layer height can definitely help, especially if you have mostly horizontal and vertical bits, with a few curved bits in between. For a rack though it's almost all curved or at least angled, so you'll need to print nearly everything at a low layer height.
The other problem is that the teeth will experience a shear force that will tend to rip the layers apart. It's much better to orient the layers in a way that the force stays within a layer. The strength within layers is generally roughly double the force between layers, CNC kitchen has done a lot of testing on that subject.
I do suspect that variable layer height might be a huge help when doing bevel gears.
I can't begin to describe how amazingly timely this was. I'm working in Blender and although it makes super gears, it lacks some of the parameters and doesn't really help with the guides or (in my case) a rack.
That's great to hear, glad it's useful to you
@@antalz Exceptionally! I'll admit I'm having to plod around and learn it a little at a time but knowing how to do it is 90% of that effort and if I do it right first time, then I won't have to worry!
@@marcdraco2189 Great, if you need any help let me know. I have 0 Blender knowledge though.
@@antalz Thank you. Blender has a gear system but it's not really up to the quality the Fusion plugin provides. You can't (for instance) insert a fillet. I suspect it was created for gears that "look" right without the real-world functionality.
Now I can make some adjustments myself but a better plugin would make a world of difference. The best I've found doesn't work on the current version though.
However, all that said, your videos have both taught an inspired me. You are an excellent teacher young man, don't ever let anyone tell you otherwise!
I understand 100% more than I did when I started all of this and you're the reason. Let me raise a glass to your health and happiness and all the best for 2021!
Nice! Thx!
Legend
thaaaaaaank you for not relying on a generator. i dont know how to implement gears, so i need them to be easily adjustable while i figure it out, which means i need parametric. seems like every video relies on a gear generator or pre-defined dimensions, which is great for if you already know what gear you need, but not great if youre still figuring that out
Would you be interested in manually drawing the gear/pinion in a parametric way? I never covered that actually, some others have but in my opinion generally not very well.
@@antalz haha, i spent several hours after that comment trying to figure out how to draw the pinions parametrically and i was able to make something that looks very much like a gear. but which is significantly (about .25mm) off of a gear generated with the same variables by fusion, and it doesnt mesh right when i try to animate it. i think youtube is sorely lacking a good tutorial on how to parametrically model involute teeth!
This video is helping me a ton already, thank you for sharing :)
one thing that will help, does the gear and rack need the same amount of teeth, or is there a ratio we can follow?
No that doesn't matter. The only requirement is that module and pressure angle match. Besides the the module*number of teeth does determine how far away the gear should be mounted from the rack, and how much rack travel equals one rotation of the gear. There's a bit more info on these words and equations in video 2.
So I was trying to design a curved rack kind set up and when I was making the curve for the shaft to slide on, it doesn't move along that curve ,, could you suggest where I might be going wrong?
Hi, since you linked the KHK site, I figured, why design my own gear when they provide the 3d model for what I need? So I downloaded their model but now I don't quite know how to mate them, is there an staright forward method to do this?
I can interpret your question in a few ways:
1) If you want to know where in space your gear should live, for regular gear-gear sets watch video 2. For a gear-rack set, I point out the pitch line near the start of the video. That pitch line must be tangent to the pitch circle of the gear, just like how the pitch circles of a gear-gear mesh must be tangent.
2) If you want to know how to add mounting features suitable for 3D printing, check out video 1
3) If you're making helical gears/racks in the normal system, check out video 3. For helical gears in the transverse system you can just use the math from video 2 without changes.
4) If you're asking about joints in Fusion360, I don't cover that explicitly but I do show it a few times in the different videos, and you can find how I did it in the example files in the description. "Mate" is also a technical term for the functional equivalent of joints in some other CAD systems, if you're asking about those, I can't help you very much because I don't have active licenses in those CAD softwares. There are tons of good tutorials on the basics of inventor and solidworks though.
For all cases the chapter markings in the videos should point you to where you need to go. Let me know if I failed to understand your problem.
I should point out that while I title all these videos "How to model X", that is really only part of the equation, and useless in a vacuum frankly. How to print them, how to mount them, where to mount them are all explicitly part of the tutorials. I should perhaps use a better title, but I felt that "how to model X" would do well in search.
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at around @2:00 in the video how do you get the line parameter to get it above the base of the rack (1.25* module) what do you get click... i select the line and the rectangle length but then i don't know whta to do to get the value window
I'm using the dimension command, using the shortcut key D.
Tough for me as a beginner to figure out what shortcuts you were using, but did eventually make it to the end. Thanks for this. My next question is: What changes would I make to the joints and motion link in order to make it so the gear rotates in one spot and the rack moves?
In that case you'd ground the shaft, and then instead of putting a slider joint on the shaft you have to put it on the rack. I think that's all. And yeah these tutorials are a bit tough if you're very new to Fusion, but I'm glad you figured it out in the end.
@@antalz I had actually tried that first, but it didn’t work. I couldn’t figure out how to make a slider joint between the rack and construction line,mor it wasn’t working anyways, so I’m going to put a rectangular base to slide with the rack. Also, would i create a motion link between the rotation joint of the gear/shaft and the slider joint of the rack?
@@sethother8012 I never tried slider joints onto sketches, you could be right that doesn't work. And yes the motion link should be between the slider and the revolute. You probably also want to ground the base you made.
@@antalz I'm trying this, but I just don't understand why it doesn't just slide in the position i started with, which is the rack's back touching a similar dimension block. I want it's back to slide up and down the length of a long 2 x 4 type shape. The first component i pick is the one that slides, and the second one i pick stays still, right? Well, when i choose the back face of the rack first, then the face of the 2 x 4 second, it gives me no x , y, z choices until i click revolute or some other motion first THEN slider, then i change to slider, but instead of making the back of the rack flush with the face of the 2 by 4, it rotates it 90 degrees, so the gear rack is perpendicular to it, and also places it upside down so the teeth are against the face of the 2 x 4, How can i make so it will just slide from the position they are in?. I kind of have to move the rack out of the way to access the back of the rack that i need to the slide, but when i click the 2 x 4 face second, i get perpendicular, like the rack and 2 x 4 form a cross and upside down rack
@@antalz I think i figured it out. So I guess you have to choose exact center of both the rack and the 2 x 4? Even if just sliding?
Hey, I'm trying to create a curved rack and used the fit point spline tool for the shape of the rack but, I can't select the line itself for adding dimensions. I can only select the green handles for the spline. Can you tell me how to get around this please??
Short answer, you can't. The curve of a spline is determined by the position of the fit points and the direction and length of the handles. Depending on what you want to do you can apply constraints to the handles and put dimensions to locate the fit points. Especially vertical/horizontal/tangent constraints on the handles can be handy.
@@antalz ok, thanks for the speedy reply!! I’ll keep working on it.
I have a problem when to make rectangular pattern. how can you help me. I am a bigginer, I just finished step by step with you and draw till the 1st tooth. cannt make the full rack. thank you
Could you be a bit more specific with what the problem is? You need a rectangular pattern of features, and then on the timeline you can select the features that need to be patterned. Do you have the timeline enabled? Have you done the extrude operations?
@@antalz after long hours I mange to do it. I had problems getting the direction arrows to appear. it kept saying choose direction and I didnt figured it out. trouly I dont know what I did to bring them. but now its sorted. Can I send you photos next time if i have problems. Are you on other social media please?
@@enginelover1 I'm on Instagram but not really active, certainly not lately. You can reach me by email at antal@creonova.nl
Hi for the motion link between a gear and the rack such as yours, what would the distance be? I can’t seem to get the motion ration correct
It should be module*numberofteeth*PI distance per every 360 degrees of rotation. If you've learned about the pitch diameter and pitch circle in video 2 that should make sense.
@@antalz thank you, I had an existing gear created with the spur gear wizard, but will look at your video on creating the spur gear from scratch. Many advantages of having this parametric as you say.
@@davidharrison865 I don't understand, I don't have a video on creating spur gears from scratch I'm afraid. I use the spur gear generator in all my videos.
@@antalz ok sorry, I’d switched from watching your video on my iPad to walking and typing a comment with my phone, just assumed you had another video. I’ll fire up fusion again a bit later today and see what I can work out. I got the motion joint set up but could get the motion between the rack and the rolling gear to rotate in sync.
I am trying to make a helical rack for my helical pinion of normal module 1.5. Would the module I use in the parameters for making the rack be the transverse module (the normal module of 1.5 divided by cosine 17 degrees)? When I do the sweep what module would the helical rack have (I’m guessing 1.5)?
I think you got it right. When doing the sketch use a (transverse) module of 1.5/cos(17 deg), your formula is backwards, the transverse module is always larger. You don't need the module anymore when sweeping right?
You can also just sketch the gear profile on a normal plane, in that case just use 1.5. For racks that's not so complicated. The two methods do have a slightly different result: the height of the teeth is based on the module, in the first method it's based on the transverse module, in the second method on the normal module. You can also just use either method and specify the tooth height that's right for you. I believe it's usually based on the normal module. So in your case addendum of 1.5 mm, dedendum of 1.5*1.25 = 1.875 mm.
@@antalz Thank you for the reply. Just to clarify, in making my rack, I have done the same as what you have done in the video, expect that my module is my transverse module (1.5/cos(17 deg)). So the addendum is 1.5/cos(17 deg) and the dedendum is 1.5/cos(17 deg) * 1.25. I have then done the sweep (and yes, the module isn't needed when sweeping). I think that this helical rack will mesh with a helical gear of a transverse module of 1.5/cos(17 deg) - do you agree? I am 3D printing the rack and pinion soon, so I will know the answer shortly if you don't!
@@Thomas-vi5yw Yeah that should work out, though if you make the helical gear yourself too, using the method I usually use, then it will have longer teeth. Shouldn't be a huge problem though.
@@antalz Thank you. I am actually making this all in Onshape which has a helical gear creator function, so hopefully there isn't a problem. Thanks for the help!
@@antalz I printed off the gears today and they mesh very well - very smooth! Thanks for the video - your method works!
I have a doubt.The distance between the inter section of the pitch line is 5 time of the module devided by 2. As the module is 2mm, 2x5 devided by 2 is 5.but your measurement is 3.142.How does this happend
I'm not sure where you get the number 5 from. In the description I link to a page from KHK gear, that diagram shows the dimensions exactly. If it seems I didn't accurately reproduce that drawing in the video please let me know.
Is the gear rack we made a Spur gear rack? Or is that even a thing?
It appears it's just a rack, sometimes gear rack to distinguish them from other kinds of racks, I don't recall anyone calling them spur gear racks.
Hi, I need to increase the overall size of the gears, like say scale it up: overall length from 188 to 6000 and the width from 20 to 200. How should I change the parameters for that? Also just wanted to add, amazing video, even a total noob like me could understand.
For the width you can just increase the width parameter. For the length you must either increase the number of teeth or the module. Do note that the module of the rack and the gear must match, you can learn more about that in video 2.
Thanks, and good luck
@@antalz Thank you so much ! I also wanted to ask , how do should I decide the distance between the shaft and the pitch line ? Like is it random or is there a like a process to decide on that. And what about the diameter of the shaft , I do remember you mentioning in the video that, that can be random
@@smrutisuresh9530 The distance between the shaft on which the gear sits, and the pitch line of the rack, is equal to half the pitch diameter of the gear, and the pitch diameter of the gear is the module times the number of teeth. In the video around 13:40 I set the distance to 20 millimeters, and I say that's because the gear will have a pitch diameter of 40mm. Indeed, when I make the gear at 15:00 I select a module of 2, and a number of teeth of 20. The module had to be 2 for the gear, because the module of the gear has to match the module of the rack. The pitch diameter of the gear is then 20*2 = 40, and the center of the shaft must be half the pitch diameter away from the pitch line of the rack, or 20mm.
@@antalz Ohhh got it ! Thank you so much ! 😁
@@antalz sorry to ask so many questions , I seem to be facing a tiny issue. When establishing the motion link , my cylinder is sliding off alone and my spur gear is rotating alone , where did I go wrong ? 😅
I wish there was a way to approximate spur gears parametrically including undercut. Otherwise you need to know all parameters of your gear upfront, especially if you're modifying them further. Numerous times I had to go back and replace a gear and then have to redo tens of downstream operations that would become invalid.
I think you can do stuff like shaft-shaft spacing parametrically, and then import the gear from another file. Then if needed you can change something you can change the parameter, and then replace the gear with another one. You can also do it parametrically, but boy it's a lot of work:
ua-cam.com/video/NaW4jWARFdY/v-deo.html
This also doesn't do undercut, but neither does the standard generator I've since learned.
@@antalz Yeah different file for the gear can still lead to the same problems if you have to extrude/align to/from gear surfaces as well joins/cuts. I guess one could carefully work around those but it's a lot of work, especially when you're not sure what you want exactly upfront and need to redesign parts. I use GF Gear Generator which seems to do the undercut and can do bevel gears, but it's still not parametric and it's limited in other ways (preset module values, no backlash etc). But on the other hand I want to have parametrical backlash, so I'll live with the suboptimal offset. Here's the project where I use a combination of helical and bevel gears ua-cam.com/video/9VcGwiHOALg/v-deo.html
@@antalz Love your videos btw, just found them. I was thinking of doing some tutorials on gears but yours are way better haha! Watched the entire series.
@@MihaiAndreiStanimir Thanks a lot! For your rewind mechanism yeah it's really painful gears just aren't parametric. The video I linked constructs them from scratch, but that's a huge chore. But if you're going to do a lot of iterations maybe worth while.
For a lot of gears you can use your slicer's horizontal expansion or XY compensation setting instead of modifying the backlash. Doesn't completely work for bevel gears I think. You can also give yourself some play in the shaft-shaft distance.
@@antalz Yeah, it's too much work from what I can see in that video. Would be great if that could be saved and insert-derived into other files. Sadly all the reference parameters become read-only :(
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Guys please anybody can send that rack and pinion which is completely done in autodesk link 🙏please