Simulation of the hobbing process of enveloping wormwheels for the calculation of contact pattern and contact lines
The contact pattern and contact line calculation is an essential part of the design of worm gears. The existing calculation algorithms are based on the law of gearing. For this reason, cases like meshing interferences can only be analysed to a limited extent. The simulation of the hobbing process of enveloping wormwheels, introduced here, makes it possible to generate any wheel flank precisely. For the contact pattern calculation, one wheel flank is generated from the cutter geometry and one from the worm geometry. These two generated flanks are brought into contact. For each flank coordinate, the distance to the opposite flank is obtained. The graphical
application of this distance over the wheel coordinates results in a contour diagram that is known as the contact pattern. The contact linecalculation of worm gears also shows on which part of the flanks power is transmitted at a certain rotational position. For this calculation, the wheel flank generated from the cutter is brought into contact with the worm flank at any angular positions.