involute curve equation for internal spli

[prabakar78]

Hi all,


Do any one have an equation to generate the involute curve for internal splines .. not the external gear data?.


Regards


Prabakar M

 

[lbotez]

The involute equation doesn't change at all. For standard module, basic rack, profile shift (if needed this is standard as well) and tolerances see spline standards (ISO 4156, DIN 5480, ANSI 92 (M)). Be sure you read the tolerancing system as well, since the generated spline will have "basic" dimensions (MMC condition for internal splines).

 

[IceFai]

you can use "from equation" option to create a datum curve.


and then use "cartesian" for csys type ,relation see attach image:


View attachment 453

 

[prabakar78]

Man,


Thanks for the time spent and the reply...


But i have a concern on this...did this equation takes care ofthe correction factor...


I have another equation which worked fine.. but i have to play with the correction factor.. to get the exact dia under pins...


Any way thanks for the effort.





Regards


Prabakar M

 

[jbuckl]

you can adjust the deviation from the involute by i) offsetting the curve in the feature sketch that uses the involute.(this gives tooth thinning/thickening)


ii) using a second coordinate system which gives an offset from the one at the centre.(this gives addendum modification)

 

[prabakar78]

Thanks for the reply...


i could not get your point clearly.. do you mean that by adjusting the offset distance you can arrive the correction factor...are those two variables linear...


and i have the same doubt for ur second answer also.. is that linear with the modification to the correction factor..


it will be helpfull if you can explain it.





regards


Prabakar M

 

[lbotez]

By offesting the curve you should get the desired result. When you add addendum modification you are just offseting the basic profile. Think of the string wrapping around the base circle: if you offset the profile you cut o small piecefromthe tip of your string. That's the same thing that happens when you shift the generating rack!


To get the correct measurement between pins create the cut with an offset, then using a feasibility study fing the right value for your offset. This should do the trick.