Study on the evolving law of meshing performance of a novel self-evolution hourglass worm drive

Under the extreme service requirements, a novel self-evolution hourglass worm drive has been proposed, and this transmission form has both precision and heavy-load characteristics. In this paper, to fully grasp the transmission characteristics, the evolving law of macro and micro meshing performances is studied. The mathematical model in the initial state is converted, and the medium gear tooth surface in a modified involute gear is obtained. Considering the tooth profile change in the whole life cycle, the control model of the tooth thickness is established, and the boundary of backlash-adjustable is determined. The mathematical model of the meshing performance under the initial state is established, and the influence of six design parameters on the meshing performance is analyzed. The evolving process of the tooth surface is investigated, and the evolving law of the meshing performance is mastered. The results of the analysis indicate that during the evolving process, the contact area in the direction of tooth depth increases in a deceleration trend, the transmission pair has good contact strength in the whole life cycle, and the lubrication performance at the engaging-in end and engaging-out end are different.