ANSI spline with addendum modification 1

[gmos]

Hi all
I am new to the gear and spline area so please let me know if any of my assumptions are incorrect. I have to design a female spline for an ANSI spline. The problem is that the outer diameter and form diameter are different from standard so I am guessing that the spline has a modified addendum which is commom for DIN splines but I haven't seen any in ANSI splines and I couldn't find anything about addendum modification in the ANSI standard.
My question is can I use the DIN 5480 formula to find the x value:
external spline major dia=mz+2xm+0.9m
or should I use the common formula which is used for gears whith modified addendum which is (for standard center distance) :
DO=mz+2x=2m
I assume that I should use the same x value (or to be specific -x) for the internal spline.
Here is some information about the spline:
External spline - ANSI B92.1 - CLASS 5-flat root side fit-13 teeth-pitch :8/16-major diameter: 43.64 mm- form diametr: 37.998mm
thanks for your help

 

[gearcutter]

"can I use the DIN 5480 formula to find the x value?"
No you can't because you'd be assuming that the major diameter is standard.

As the modified form diameter is only around 0.10mm less than the standard but the modified major diameter is almost 1.0mm less than the standard; it would appear to me that all that's been done to your modified spline is a 'topping' of the major diameter.
What's more important is ensuring that you have the circular tooth & corresponding space thicknesses matched correctly.
For that you'll need the dimension over pins (plus the pin size) or the base tangent measurement values.


Ron Volmershausen
Brunkerville Engineering
Newcastle Australia

http://www.aussieweb.com.au/email.aspx?id=1194181

 

[gmos]

Thanks gearcutter,
I agree with you. I have the tooth thickness and the over pin measurement and I was wondering why the effective tooth thickness is similar to the standard value. Thanks for the valuable guide.