An Analysis On Meshing Performance Of Offset Cylindrical Worm Gearing And A Study On Worm Processing

Offset involute cylindrical worm gears is a composition of the transmission by the worm and worm wheel meshing, which is characteristic of small size ,big transmission ratio, low vibration and noise. This paper mainly studies on the worm which is a involute helical gear with few teeth in substance orthogonal to the face gear (ie worm gear). The meshing performance,optimization of parameters of the second quadrant of the offset involute cylindrical worm gearing and the screw worm tool's design is the primary concern. The content of this research is as follows:Firstly, based on the theories of the differential geometry and gear meshing, mathematical model of the second quadrant of the involute offset cylindrical worm gearing drive is established by kinematics method. Derived function of the worm meshing, meshing equation, worm wheel's tooth surface equations and the boundary line equation of worm screw gear tooth surface are also deduced.Secondly, according to the theoretical equations of the second quadrant offset involute cylindrical worm gearing drive, in the light of their mathematical model, the meshing of its performance is simulated. The influence of design parameters on involute offset cylindrical worm gearing drive is emphasized. Analysis showed that an appropriate increasement in helix angle, increasement in modulus, reduction in worm gear teeth, reduction in the number of worm head , increasement in the heliciod working length of worm gear can improve the distribution of contact line, which can make the transmission performance better.The last, the research in processing the well-established involute helicoid worm tooth has been done. The use of profiling method of processing principle and the use of contact line method turn out contact conditions between a disc cutter and the workpiece surface spiral surface. The disc cutter axial truncated map is designed by programming software. At the same time, the deflection of disc cutter axial truncated map is also studied, which is caused by the modified gear.