Internal/external spline definition

[borjame]

All, I'm trying to define an internal spline for a mating shaft to an already defined external spline. When I go the Machinery's Handbook 26, the major dia of the internal and external spline (Dri and Do respectively) are defined exactly the same way as N+1/P. Since they can't be exactly the same am I correct in assuming this is the "perfect form" and that tols and what not need to be accounted for in the design? I see a correction factor cf defined as .001*D, but when I plug this number into the Form Diameters for internal spline I still don't get the supplied numbers.

The numbers supplied are:
angle - 30 degrees
diametral pitch - 16/32
# teeth - 32
pitch dia - 2
eff chordal tooth thickness - .09095

major dia - 2.0706 (I get 2.05??)

Am I missing info or just knowledge?

 

[dimjim]

Mine shows Do equals N + .80/P
but my Handbook is the 17th Edition.

 

[gearcutter]

As per the 26th edition Handbook:
For 30deg P.A.
Flat root side fit: major internal diameter = (N+1.35)/P
Fillet root side fit: major internal diameter = (N+1.8)/P
Flat root maj diam fit: major internal diameter = (N+1)/P

Mating parts having the same nominal major diameters are for "Flat Root Major Diameter" fits only. The standards show how to calculate the clearances.


Ron Volmershausen
Brunkerville Engineering
Newcastle Australia

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