Helical Gear from Spur Gear Pattern

grabcad

Model is parametric and relation driven. Variables include pitch, tooth number, pressure angle, addendum, deddendum, face width, helix angle. By changing parameters, any helical gear may be created. Model contains involute form drawn two ways (one with cylindrical coordinates, other with parametric); both curves from equations, and the helical tooth was formed by a sweep. The sweep trajectory was created with a curve from equations. To change spiral hand, go to curve from equation for trajectory and locate equations: r=DA/2 theta=F*tan(beta)*360*t/(pi*DA) z=F*t Put a - sign in front of the F in second term. Tooth rasius below base circle diameter was faked in.