A precision generating hobbing method for face-gear based on worm hob

In order to improve the machining accuracy and production efficiency of face-gear, a method of face-gear generating hobbing by worm is provided in this paper. The principle of face-gear hobbing worm is analyzed, and the mathematical model of the worm is presented based on the principle and the theory of meshing. Taking the hobbing needs into account, the special machine tool is provided, and the movement control method of face-gear hobbing by the worm on the machine tool is proposed. The equation of face-gear tooth surface is calculated, and the 3-D model of face-gear is established based on CATIA software. To reduce the face-gear tooth profile errors induced by ratio errors, an error analysis model of face-gear hobbing is established. The experiment is carried out, and the completed specimen is detected by Coordinate Measuring Machining (CMM). The processing parameter is amended according to the tooth flank detection results, and the maximum normal deviation of the whole tooth surface of the face-gear specimen is improved from 243.2 µm to 61.0 µm. Experiment results demonstrate that the method of face-gear hobbing by worm is an effective approach to achieve the precision face-gear with high dimensional accuracy.