InvGears.scad

I had trouble with my RC car design, needed to get the gearbox working much better.
So, I created InvGears.scad.
See
http://www.thingiverse.com/thing:1643825
All files NEED OpenSCAD version 2015,03-02 or later they will NOT work with previous versions.
InvGears.scad is meant to be used as a library for use in other scad files.
Everything is still very much work in progress.

Example.scad demonstrates it's real use.
This contains a parametric 2 stage, 3 axle gearbox.
Variables near top of file control the parameters of the gear box:
Pitch sets gear tooth size and therefore ultimately controls size of gearbox. On my printer 0.7 is about as low as I would go, 0.8 for higher print quality.
The rest of the variables are documented in the file.
Un-comment gAssy() to see just the gears, use OpenSCAD View|Animate menu to see the teeth movement for adjusting Pressure.
Typical gAssy() view:

Comment out gAssy() and un-comment Assy() to see full assembly.
Typical Assy() view:

Comment out Assy() and un-comment print1() to get printer plate of housings (parts shown in white above).

Comment out print1() and un-comment print2() to get printer plate of gears (parts shown in red above).

In both printer plates there are extra cubes.

I created my printer in 2013, it's a RepRap metric Prusa with home made hot end:

Your printer probably creates better quality prints, to be honest I have no idea how the quality compares. You will see that my printer has NO fans, I find that adding cubes to my prints allows the plastic to cool down between layers so that it doesn't go wrong, the cubes are my alternative to fans.

I did say that the files are work in progress, the Example supports Spur, Helical and Herringbone gear types only.

InvGears.scad:

The file can be used on it's own to see how it all works.

There are 3 variables near the top of file:

iDemo = 0;

Set this to 1 and the you will see output.

Variables similar to those found in Examples.scad are further down in file, these control what is shown in demo.

iShowC = 0;

Set this to 1 and you will see the 4 circles of interest for the gears.

Please refer to http://www.cartertools.com/involute.html by Nick Carter to fully explain.

The 4 circles show Outside, Pitch, Base and Root as explained by Nick Carter and shown in his first drawing.

It also shows the 2 radii that define each side of main tooth.

iShowT = 0;

Set this to 1 and you will see the involute point calculations, radii and tangents.

These show up best with Rim, Adj and Typ all set to 0.

This is explained best by Nick Carter in the rest of his drawings and explanations.

Once you get to this stage you can alter the other variables and see the difference they make clearly.

Don't forget to set iDemo, iShowC and iShowT back to 0 before using the lib in your files or Example.scad.

InvGears.scad also includes bevel and cycloid gears, but I have not yet created an example for those.