New technology for manufacturing quasi-globoid worm gearings

Abstract

The advantage of the globoid worm gearing, that all teeth of the worm are in mesh in every moment, is well-known. The main advantage of the helical worm gearing, the easy production is also known. The paper presents a new gearing construction that tries to combine these two characteristics in one novel worm gearing. This solution, similarly to the manufacturing of helical worm, applies turning machine instead of the special teething machine of globoid worm, but the path of the cutting edge is not parallel to the axis of the worm but has an angle in the vertical plane. The resulted in form is a hyperbolic surface of revolution that is very close to the hourglass-form of a globoid worm. The worm wheel then generated by this quasi-globoid worm. The paper introduces the geometric arrangements of this new worm generating method then investigates the meshing characteristics of such gearings for different worm profiles. The considered profiles are circular and elliptic. The meshing curves are generated and compared. For the modelling of the new gearing and performing the meshing analysis the Surface Constructor 3D surface generator and motion simulator software application was used.