DIN 5480 Involute spline calculations 2

[TOPPTO]

Hi,

I have a couple questions for the masses here.

I have a German copy of DIN 5480 from 1974. I would like to know where I can find an English version of the entire standard. I have found a few sites that will sell this standard in parts but each part costs about $100.00 and there's 16 parts.

My second quesion is if I have to buy the separate parts which part has the calculations for the involute creation? Along with that I am looking for the classes of fit information. How many are there and what is the relationship to calculating the involute?

I created an AutoCAD AutoLISP routine several years ago to draw a true ANSI involute spline. I am now needing to add DIN to this program and will need to add JIS soon after. The english version of the DIN would help me find out if the calculations I already have can be used and what I will need to change for the class of fit.

Thanks in advance for any help offered.

Top PTO

 

[gearguru]

Part 1: most calculations
Part 14: Tolerances (side fit)
For what you need the "true" CAD representation of a spline?
Do not forget about the fit, tolerances, etc. if you really need the perfect drawing. Knowledge of metric (ISO) fit system would help also.

 

[TOPPTO]

Thanks Gearguru,

I think that will get me started. Does part 14 explain the fits? For example one of the splines that I need to draw is W35x2x30x16H. I need to know what 16H is and how that affects space width.

We draw the true CAD representation to send to our vendor to produce EDM bores for us. They use the cad file to produce the EDM profile.

TopPTO

 

[gearguru]

TOPPTO,
Yes,it does.
The example (W35x2x30x16H) is not correct, it should look like W35x2x30x16x7h. The small letters for fits are used for external features, capital letters for internal features. Your spline is external - on a shaft (W means Welle = shaft), 35 is the reference radius in mm (OD is slightly smaller) module 2, pressure angle 30deg, 16teeth - and 7h would describe the tolerance size (7) and location (h).
In metric splines the rule is to use the internal spline with the H tolerance and then combine it with f or g or h etc. external spline. The H/h fit theoretically can create the "line on line" (zero backlash) fit if both parts are made in MMC. We usually use f or g external tolerance fits to create some mandatory backlash by design.
As you see the knowledge of metric fits is necessary when we work with metric drawings/standards. We discussed all these spline and fits problems long time ago here.

 

[TOPPTO]

Thanks Gearguru.

I will search for those posts on spline fits. Hopefully they are still here. If they are, I'll find them.

You know I found this site by accident. What a cool place this is! This site will be the penicillin to my mold. Thanks

TopPTO

 

[gearguru]

TOPPTO,
Welcome to these fora!
In my previous post the 35 means reference DIAMETER, not radius. Sorry!
You mentioned that you created lisp spline program; you can find here also the gear lisp program by Diamondjim. Involute spline is actually a gear with the special tooth height. Most gear geometry formulae are valid for splines also.

 

[diamondjim]

We all knew what you meant.
Nice to see gearguru back
on the forum.