Modeling an Equation Driven Involute Spur Gear in Solidworks
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- Опубліковано 6 вер 2024
- The method given in this video works when diameter of base circle is bigger than that of the dedendum circle.
When the number of teeth is increased to big enough, the base circle diameter will become smaller than than the diameter of dedendum circle. Then the gear profile will be all involute. One can use similar approach given in this video for such case.
The tutorial file for this video can be downloaded from
drive.google.c...
Wow, wish I had Dr. Cao as my professor. What an excellent demonstration and accompanying material. Thank you for making this accessible to everyone!
Great tutorial, sir!
Just one note: when creating the circular pattern, one might need to be sure to have the "Geometry pattern" checkbox checked in the circular pattern dialog box, otherwise it might not let one propagate the fillet as well
Damn it. I just lost an hour erasing and redoing everything step by step. I was going crazy until I figured it out on my own.... I was going nuts! Now that I'm reading your comment I feel trolled xD
BTW great tutorial Yang Cao, but you should have used an equation in the circular pattern, that's pretty obvious. So you don't have to manually adjust it every time. Number of patterns must be equal to "N". Same thing for the fillets, you could have used an equation like "fillet radius equals 0.5*clearance" or sth like that.
You are a gentleman and a scholar. Thank you so much for this comment.
I had an issue with that, but I changed my fillet so that it was included in the sketch, and then set it to an equation.
Thank you sir. True legend lol
thanks alot for this
Thank you so much for this great tutorial. I'm really glad to learn the equation driven function for drawing the involute, instead of drawing numerous tangent lines and confusing myself. You've helped me out so much!
Thank you so much for this. Absolutely spectacular. I'm using this to make a clock, and I found that by simply inputting "N" for the number of instances in the circular pattern you can have it auto update. Also, I made the diametral pitch dependent on the pitch diameter via adding another variable. Just a couple things to make changing gear sizes easier.
Can you explain why you made the diametrical pitch dependent on the pitch diameter? What does this solve?
Matthew Miller I'm using SDW 2014, not sure if it will work on older versions. I simply put "N" (without quotes) into the field "Number of Instances" when I did the circular pattern. This way I can make a bunch of different size gears without having to update the number of teeth in the equations AND the circular pattern. As for the pitch diameter, I just made another variable (named pitchdia I think) and changed the value for "P" to an equation based on "pitchdia." This really doesn't solve anything for most practical uses, but when you're making a bunch of different sized gears, it shaves a minute or two off each one.
Super helpful video. Some advice would be set the number of instances of your circular pattern to "n" and the fillet to a fraction of "c" (for example he used R.10 with a .125 clearance, so you could set your fillet to 4/5*"c") to ensure it will never be larger.
Thank you so much! I am helping a client design a machine utilizing a few existing parts and needed to create gears with a dimetral pitch of 4.62. I couldn't make it work, but with this, it was a breeze!
I wish, I had lectures like these 10 years ago in university. Great tutorial! Thank You!
Thank you for sharing!
Note: to write equation you may need to write with " " the variables.
Improvements:
- Number of tooth can be linked to the circular pattern instances
- Fillet radius can be setted as Diameral Pitch / 10, this prevent manual adjust
- Alpha calculation is not required, simply link the line to the intersection with Diametral pitch, than simpler equation as 360/4/N.
- Not necessary to write two equation, can be used one than mirror it
Circular pattern when linked revert back to same value any idea
Why pattern 20 when he got 18 teeth? it happened to me when i designed my gear (different characteristics)
Hello, thanks very much, you saved my life :D
Just a suggestion, to automatic define the root fillet, i used 0.8*c, so we got 80% of clearance (a safe value).
For number inside of the circular pattern could you not just call the variable "number or teeth"?
Your video has certainly helped my team design our own gears for a design project. Your video is very clear and concise. Thank you Sir.
This is fantastic! I was able to follow along using OpenSCAD instead of Solidworks because of how detailed your explaination was. It also cleared up a bunch of questions I had regarding gears in general. Thanks for sharing!
Thanks Yang, the tutorial is detailed and easy to follow. Save me tons of time!.
Great tutorial. This video captures the difference between hobbyist level CAD and actual mechanical engineering XD
In SW 2013 if you double click the pattern and edit the dimension in the view window, you can enter the global variable there. This also works for helix.
Hello, I very much enjoyed your presentation and demo, excellent, you kindly explained all the steps and it was relatively easy to follow, much appreciated. Thanks.
Thanks for putting together this video, really appreciate it. Comprehensive and easy to understand.
屏幕录像专家。。。记得当时看黑客视频就是用这个软件。
现在在油管上看到了，满满的回忆啊
According with the TXT this Equation is wrong in my SolidWorks:
sqr(dp^2-db^)/db*180/pi -phi
The correct Equation is gonna be this one:
= sqr ( "dp" ^ 2 - "db" ^ 2 ) / "db" * 180 / pi - "phi"
same here. thanks.
No it would be
= sqr ( “dp” ^ 2 - “dp” ^ 2 ) / “dp” * 180 / pi - “phr”
This is an amazing tutorial, thank you very much for taking the time to make it and sharing it with the world!
Well, that's about as good a demo as can be done. Nice job, sir. And thanks for a solid technique.
Equation Driven Curve:
"D2@Sketch2" - Circle Name from which is shape created
"D2@Sketch2"*.5*(cos(t)+t*sin(t))
"D2@Sketch2"*.5*(sin(t)-t*cos(t))
Mirrored Curve:
"D2@Sketch2"*.5*(cos(-t-2*"D4@Sketch2"*pi/180)-t*sin(-t-2*"D4@Sketch2"*pi/180))
"D2@Sketch2"*.5*(sin(-t-2*"D4@Sketch2"*pi/180)+t*cos(-t-2*"D4@Sketch2"*pi/180))
Remember you need to be in Sketch2 to make it work.
Very good work. I have now a complete parametric gear !
Thank you very much !
Dr. Cao, thanks for posting this! Now to find out why Solidworks fails at 39 teeth (when the dedendum circle diameter is greater than the base circle diameter).
+Jeff Biss
Have you, by any chance, figured out yet why it fails at 39 teeth? I'm experiencing the same problem.
+tobyteddy222, nope, I have not figured out why. I have contacted my reseller and they said that they are looking into it, I sent them my part file. I think that it has something to do with base circle being a smaller diameter than the dedendum circle. If you look at the results of 39 teeth, you'll see that the tooth base produces "notches" with the involutes. Trimming the dedendum circle and each involute turns one of the involutes red and the "The sketch has not been undated..." message is displayed. I will post any resolution when I get it.
+tobyteddy222, I still haven't received a reason why this fails but have developed a work around:
1. Open an new sketch on the same plane as that which holds the equation driven involutes.
2. Select the involutes and the base (dedendum) circle.
3. Click Convert Entities. Those features are now copied onto the new sketch with no equation driven relations between them. They can now be trimmed as required so that you can use the new sketch to Extrude Cut the disc. After you extrude cut, simply create a Circular Pattern using that Cut-Extrude feature and you're done!
You can now create spur gears of any number of teeth up to 105. There is a problem with this method because 360/(4*N)-alpha equals zero when N = 105.3916. So, gears with 106 and more teeth will fail.
why does this don't work when I go to more teeth? it collapses in 42 teeth. the dedendum circle becomes bigger than the base circle and it doesn't work. it is a great tutorial but I've been struggling with this all day long...
thats bad
it probably has to do with the pressure angle you're working with. remember that if we want to constrain the dedendum and base circles, we can express their relationship as:
(pitch diam) - 2(dedendum) < (base diam)
with pitch diameter equal to (module)*(num of teeth), or (num teeth)/(diametral pitch) and base diameter equal to (pitch diameter)*cos(pressure angle), just like the textbooks give us.
you can solve for your max number of teeth by moving all other variables to the opposite side, but you should see that the num of teeth at 20 degrees pressure angle is mathematically limited to like 41 or something.
I just wanna thank you for this, this is an incredibly helpful tutorial and your other videos are very helpful as well. You're a fantastic professor. I wish SolidWorks had a gearing tool though. Also, it would be helpful if you could speak up a little bit in your videos.
Excellent video - very helpful. One question though. At 9:45 you enter 0.68 into the T2 field. What does this value represent, and how is it derived?
That is just a value for "t" I randomly selected after a few trial.
he chose 0.68 so he can put bounds on the curve of that first involute line, otherwise it would keep plotting for all infinite points of t (reference for anyone else wondering)
this determines the length of the curve from the start . it is the end point of the curve. it just needs to be long enough to go past the outer edge of the gear body so you can trim it later. type 2.00 in that field and you will see what happens.
This is best video about gears in SW! Pro. Thank you!
Would it be possible to mirror the second involute istead of using another parametric curve?
thanks for the tutorial, very good! Can you give me a solution for a number of teeths >420 and metric module 4?
finally sb who knows his shit. though those long ass equations in the notepad could be given in desription to copy
Thank you so much!! I needed to crank up a bit but it was totally worth it!
Im so happy I can make gears now!!!!
It basically saved my life thanks sir
to clarify.. when you input your equation curve, the genereated curve goes from left to right...0 degrees, to the right, with the given equation... my line goes up... from 0 degrees, vertical...I have No idea why its doing this. I even went back and did it with all your numbers..
I made the same mistake. You probably wrote the Y(t) equation wrong. My error was putting a plus instead of a minus lol
Dr Yang, really helpful video. Question from my side (couple of years after your video and the majority of the responses)
But, can you please describe / explain why are you using "t2=0.68" which such value?
I've reviewed your material, and I don't see, yet, the correlation
Could you please help me to understand?
Thanks
I played with it. I could be totally wrong but I think t2=.68 just guarantees the involute curve will extend past the addendum circle diameter. Like if you made both t2s=.75, the gear would still be exactly the same.
Hello Mr. Cao. I am trying to create my initial equations just like you do on the video. However, I am not able to do so. After I enter the Global Variable name I press enter and continue to the Value/Equation area. Once there, I enter the value I want and press enter, but it does not accept the value. I cannot continue beyond that point. Hope you can make a suggestion to my problem. Thank you in advance.
any odds you could make the drive public?
great job displaying the exact equations necessary to produce a gear that can be changed with only a couple variables.
Could you produce a video teaching us how to build equation driven helical bevel / miter gears?
Unreal tutorial! Thank you so much!
Hello Sir, can you please make a video on internal spur gear involute shape as well? I am struggling to design it. It will be very helpful for me in my research field
Thanks for the demo. I noticed on SW14, that for the circular pattern, I was able to set the number of instances to be the global variable N so it auto updates. Also the fillet radius can be set to "c" / 3 or 4 or whatever.
Good to know. Thanks for the information.
Thank you for the post! Helped me immensely!
One mistake that I noticed is during the circular patterning of the filet and extruded cut. The number of instances should be set to the global variable "N" rather than the number 20 which is shown.
The old version of SolidWorks does not allow to do that.
I am using solid works 2016, and when I set the number of instances to global variable N it simply substitutes the current value
Awesome tutorial! I think you can also drive the fillet and circular pattern using equations. That would make it a little more time saving. Thanks again for this tutorial! =)
Great tutorial, but wouldn't be easier to make the second involute curve as a symmetry from the first one (via the constrution line)?
Nice info,thanks for sharing it with us, well done :)
I really appreciate your effort. I am just beginner of solidworks and followed your lecture and got it. As you mentioned I encountered the base circle diameter is smaller than dedendum circle diameter. Do you have other lecture for this or should I draw from the beginning? Please let me have your tip for this. Thanks in advance
Thank you so much sir!! I m really greatful!!
Do you have similar explaination for Internal Spur Gear Modeling?
why the tooth Involute curve created by equation is not defined? it color is blue.
where does the 0.68 come from in the involute curve parametric equation
Hi there, on your notepad, the alpha equation is different than shown on the PDF. It is wrong?
If you're referring to the *180/pi, this is the conversion from radians to degrees.
This is here because the equation calls for radians, (notice "phi rad"), however our pressure angle is in degrees
This method looks pretty strong
Thanks for uploading this, it really helped me understand the process a lot more.
I have made my version of your model, are there any conditions that need to be modified to account for a much larger spur gear? I am trying to model the angle but my value comes back as a negative value and cannot define the angle.
Diametral Pitch = 0.3333
No of teeth = 110
Pressure angle = 20°
Addendum Diameter = 336mm
Pitch Diameter = 330mm
Base Circle = 322mm
Dedendum Diameter = 322.8mm
My tan and beta angle values in the involute curve come back with a value of -0.3°
Has anyone used this to create a relatively large spur gear?
Thanks a lot Mr. Yang Cao.
Very good! Two question. The parametric part remains blue is it still undefined then?
Thanks a lot for this awesome tutorial. Till now, it is the best one with scientific basis. The voice is clear, the accent is very good, and referring to lecture is very nice. Can you please tell me why the "base circle diameter=Pitch circle diameter*cos(Phi)"?
khkgears.net/new/images/basic_gear_terminology_and_calculation/Fig.-2.6-Working-Gear-Nomenclature.jpg
This is the link to a picture, on which you'll see that it's a simple right-angled triangle
I really love it, job well done!!! You have won a new subscriber :)
Excellent video
Thank you my Teacher
How do you create a curve with profile shift?
Great video! Helped me a lot. Just one comment. When you named your global variables, you called "P" Diametral pitch but I think that should be the pitch diameter (in) and you called "dp" pitch diameter when that should be diametral pitch(teeth/in). The values are correct though. Thank you so much for your help.
while draw the equation driven curve, how did you come up with t = 0.68
See Chad Wassink's comment below: Yang Cao replied "That is just a value for "t" I randomly selected after a few trial. "
@@harmonytan6746 Lmao. I was just wondering about that
THANKS a bunch from australia :)
Very usefull material. Thanks a lot. When you say "a" need to hear "b" as well. Don't you have a tutorial for internal involute gear too? Hot to direct involute curve toward center now?
Thanks
Can I add the module in the equations instead of updating manually??
And add also the relation between module and number of teeth and the pitch??
Hello Sir, Kindly provide me access to the drive file... Thank You !
Thank you so much for this sir !! this is Absolutely well done and very helpfull !!
Very helpful video. Thank you very much!
Can u make the same tutorial for Bevel Gears? Thanks.
Great Work Many thanks
Do you have vedio on helical gear tooth cut ..like you showed on spur gear
We can't see your equation for alpha in the equations manager.
Can we have access to the tutorial you used as base.
Great video. Used this information to make a template using a design table for not only spur but helical gears as well. The only thing I am unsure of is what determines what the clearance, or fillet radius, is. Does anyone have any knowledge of this?
Is there some reason why can't you just mirror the first involute curve across your centerline instead of modeling a separate equation driven curve?
I am unable to add new global variables, only one is being entered ... what to do ?
Awesome tutorial. Thanks!
How can I alter this to make less than 13 teeth possible?
i have a problem in equation driven curve . .
it says wrong equation i just copy paste it?
X(t) = "D2@Sketch2"*0.5*(cos(t)+t*sin(t))
Y(t) = "D2@Sketch2"*0.5*(sin(t)-t*cos(t))
+John Medina If youre still having this problem, all you have to do is copy and paste the formula into the x_t and y_t boxes, and you'll notice that the formula turn red in colour which signifies that it has an error. For some reason solidworks doesnt like having things copy and pasted. After this, just click the 'explicit' check box, and then click the 'parametric' checkbox again. It somehow makes solidworks forget that it was copy and pasted and the formula will turn black and it should work. If that doesnt fix your problem, you may need to change D2@Sketch2 to D2@Sketch3 if youve accidentally done it on a new sketch. That worked for me
+Sam Isaac I think if the formula turns red you have a problem with the formula. My issue was having multiple sketches/dimensions not lining up with equations, such as - Equation for Xt in the 2nd involute"D2@sketch2"*0.5*(cos(-t-2*"D4@Sketch2"*pi/180)-t*sin(-t-2*"D4@Sketch2"*pi/180)). Problem I found was that I had D4@Sketch2 on a separate sketch! D1@Sketch3!To maintain consistency/efficiency I kept the formula and changed the sketch to match.
+John Medina i am facing the same issue . .no mater what i type in it says invalid
nice thanks
Could be you have a different language version in SW? I.e. in
german "Sketch" is called "Skizze", therefore straight copy/paste
wouldn't work for involute equations.
do you realize that you patterend 20 teeth but your # of teeth in the model parameter is 18? Is this an accident or intended?
How can i do in other to copy the function in Notepad and paste it in solidworks?
thnk u for the video, my problem is with m=2.5 angle pressure 20 ans nbr of teeth 45 the base diametre is higher than the dedundum cercle diameter how can i solve this please
when dedendum lies above base circle, i found an interesting thing. involute profile generated from base circle cuts pitch circle somewhere between addendum circle. Would you please help me through this problem?
I have the same problem. But I guess you will have to change the sketch for these cases. My solution was to make the base at dedendum, in which case the fillet would be between dedendum circle and the involute curve.
Yucel Sert This isn't a good idea because having a base of the wrong size will lead to improper geometry.
Hi Dr Yang Cao, Thanks for the video! it help a lot, but I noticed the link for the tutorial file isn't working any more, I wonder where I can download it again, it's very good information.
I followed your instructions.. just putting in my own numbers for the variables at the beginning... and my first equation curve is completely wrong. im not sure why. sw 2016
Very nice tutorial Mr Cao, I have a question, do you know, how to design a rack and pinion (obviously I learned how to do a pinion), but I cannot to draw a rack to matching pinion with, I will be very happy, If you could do that. Thank you very much.
Fantastic tutorial
How to make tooth chamfer in a gear?
Great video sir!
Have you tried to build a non circular gear with involute teeth? Something like gearify but with involute teeth. Would be great!
What should I do, when it is saying
Unable to create instance for the pattern. Try again by decreasing the number of instance or the distance between instances
hI, on the begining when I write "p" then I write Value =2 and try to confirm this value by enter, nothing's happened. In your case you have the possibility to fill the comment. I have not. What i am doing wrong?
Same with me but no one answers
Would it not be a simpler method to mirror the first involute profile over the center line?
simplification: alpha = tan(phi)-phi or ?
what about profile shift?
Is it possible not to use alpha?
Let's say the straight line attached to involute curve is line "A". What if I draw a line "B" from center to where involute curve meets pitch circle where D=9. Then draw another line "C" from center at 360/4N degrees from line "B". Then mirror involute curve and the straight line "A" attached to it accross line "C".
I tried this which should make sense, but then angle between line "B" and "C" is 4.2 degrees instead 4.15 shown in your video. Which part did I do wrong?
There seems to be a limit to the number of teeth you can have given a specific a and d because eventually the base circle, which is Dp * cos(phi) becomes larger than the d circle. Is this a real property of these gears, or a side effect of the way we drew it?
Yes. I mentioned the issue in the description of the video. It is possible for the base circle diameter to be "smaller" than the dedendum circle diameter. Gear profile will be all involute. No more straight line between the base and dedendum circle. I haven't been able to figure out a general method to accommodate both cases.
Yang Cao
Ah sorry, I should have noticed that in the description.
How would I modify the equations to suit a gear with a large number of teeth?
good morning, i have a problem. when i put the value of the number of teeth equal to a high number, like in my case 94, it creates between two teeth a strange thing, how can i do to remove it?
thaks for your attention
Hi, I would really like to know what needs to be changed if the base circle diameter is smaller than the diameter of the dedendum circle? None of the videos on youtube has a solution for my question.
How can I adjust the equations to make gear with different diameters? If I adjust the "P", the size of the teeth changes also such that the new gear cannot fit into the original gear. How can I change the equation so that I can make different size gears that can still work with the original gear?
How can I incorporate profile shift as well?
Why t1 is 0 and t2 is 0.68 in equation driven cure "D2@Sketch2"*0.5*(cos(t)+t*sin(t)) and "D2@Sketch2"*0.5*(sin(t)-t*cos(t))? Any clear description please ?
M A Motin Sobuj hello did you find this out? thanks
M A Motin Sobuj He (the teacher) said about this: "That is just a value for "t" I randomly selected after a few tria"l.
It's the beginning and end of the curve. You can use other values for t_2 as well, as long as the curve ends outside the material (and can finish the cut).