Wednesday, March 16, 2011

Homemade Roots Blower: Second revision of the rotor profiles

Hopefully This will be the final designs of the Roots lobes before I start making it.

I decided to design a 3 lobe and 2 lobe rotor that would be compatible with supercharger case I designed, I will see which works out best by testing it in use. I will most likely make the 3 lobe first since I feel that the 3 lobe design is better.

I do not have any keyway broaches, for now I will just have drilled holes for the keyways. I plan on using a 1/8 round nose endmill to cut grooves into the shaft so that i can insert a 1/8 inch metal rod to lock together the rotor and the drive shaft. No idea how well that would work out though.

This 3 lobe is significantly smaller than what I had originally planned mostly due to the size restrictions of my small mill. The entire assembly is much smaller too.

Some advantages I see with the 2 lobe rotors is using less raw materials to make one and less machining required. Unlike the 3 lobe above, the centers of radii is different between the male and female lobes. I designed it this way because when they are equal, the center section becomes too thin to properly support the rotor.

I also made a rotor profile that just looked like an oval blob, was surprised that it actually works but the swept volume was very low so it's not very practical.

Next I will probably try to make a lysholm style rotor.


James Ammons said...

I would like to try using that cad model as a base is there anyway i can get the files i am thinking of using it on a r/c car of much smaller size... but i think that the idea is a good start

Anonymous said...

I wasted almost an hour using that profile before I realized its completely retarded and you don't know what your talking about.

Anonymous said...

I agree with the other anonymous, but getting the epicycloid parametric equation to go through in solidworks is even more nerve-racking

Anonymous said...

This might help you?

BrekiBMW said...

Please upload project CAD

Unknown said...

To those that have left negative comments. Your sarcasm does not bring anything useful to the project. I have built small roots blowers with rotors that have a 60 degree helix. The twisted rotors can be machined without having a forth axis. I machined a 1/3 of the rotor and using an indexing head I rotated the rotor twice at 120 degree indexing. I spent a considerable amount of time developing the arc–cycloidal rotors but I worked at it until I achieved a curve that keeps the rotor mesh within .0002. When setup with clearance the .0002 is as good as perfect. I will offer a clue that will be helpful. First use a CAD program, without it you will need to be Ienstein. when you turn rotor A +30 degrees and rotor B -30 degrees then the circles representing the lobes must be tangent to one another. Once you achieve that it will become evident what you need to do to achieve the proper mesh.

Have Fun,

George C. Fitts said...

Thanks for your sharing, NETDUKE! I like this Homemade Roots Blower: Second revision of the rotor profiles very much.

Oscar The Cow said...

Do you have a CAD download of this? I would like to build my own for a project I'm making.