[Question] Making involute gears?, special curve shapes Options

[jbayless]

Hello,

I'm hoping to draw involute gear teeth (http://en.wikipedia.org/wiki/Involute_gear).

An involute is a special curve that describes the path of a fixed point on a taut string being unwound from a circle. According to Earle Buckingham in Analytical Mechanics of Gears:

"At present time the involute curve is used almost exclusively for spur-gear-tooth profiles that are employed to transmit power. It meets all the requirements for a gear-tooth profile and, in addition, has so many unique and valuable properties that it stands in a class by itself."

Anyway, most places I've checked online say that I should just draw a simple gear, and mark a call-out for an involute gear tooth profile. That would be fine if I were ordering them from a shop, but I'm going to be cutting the gears myself on a CNC waterjet cutter, directly from the DXF file that Solidworks exports. So the more accurate the DXF file is, the better my gears will be.

I'm just wondering, does anyone know how to generate an involute curve in Solidworks? Or even how to approximate one from splines?

Thanks!

Jacob

[Annika Nauheimer]

Hi Jacob,
There is no way to directly create curves from an equation...
I am not sure if this really helps but you can give it a try
1. Create a set of co-ordinates as a table, using your formulae, in Excel. (Remember to include a third column of value zero if you wish to create a 2D curve).
2. Save this table out as a .txt file
3. In SolidWorks: Insert > Curve > Curve through XYZ points and browse to the .txt file > OK
This will then plot a curve that is driven by the points generated in Excel.

Annika