Abstract: To improve the meshing performance of ZC1 worm gearing,it is necessary to analyze the instantaneous contact line of the worm gear tooth surface.Established the mathematical model of double-enveloping ZC1 worm gearing for automatic escalator based on the theories of the space meshing.The worm wheel tooth surface instantaneous contact line equation are established.At the same time,the curve of worm wheel tooth surface instantaneous contact lines are described with MATLAB,and the influence of the main design parameters on the distribution of instantaneous contact line is analyzed.The results show that center distance a,radius of tooth profile of grinding wheel ρ and lead angle γ have a certain effects on meshing performance.

Key words: ZC1 worm gearing, double-enveloping, instantaneous contact line, meshing performance