Create a gear/knurl in AutoCAD

[bettsaj]

I want to draw a knurl with an o/d of 19mm by approximatley 16 tpi.

I have drawn a circle of 19mm, and i now need to work out how many teeth that will be for the circumference of the part. I've worked out the circumference as 19 x pi which equals 59.69026

For some reason I just can't get my head round the rest of it, what angle the teeth should be, etc..

I want to do a polar array within the circle, but i want the teeth to be complete with no gaps and to join up at the end correctly.

There must be a sum for this or a work around that i haven't thought of...

Please help!!!

 

[chicopee]

First, you must understand how the cycloidal tooth form is generated; then you must know certain terms and their related calculations used in gear design such as diametral pitch,pitch, pitch diameter,root diameter, outside diameter,addendum, dedendum, etc...Once you get the correct tooth form for one side of a tooth, then you can mirror for the other and then you can do a polar array.

All preliminary calculations should be carried out to at least four decimal places if you use english units. If you dont, the polar array may create an overlap of teeth.

I suggest that you get a mechanical enginering handbook or the machinist handbook to learn how a cycloidal curve is generated and all related terms and calculations.

In ACAD there is an easier way to create an approximate cycloidal curve, however it is not the exact way.