Abstract: A physical model for grinding face gears with six-axis CNC cylindrical gear grinding worm wheel machine tool is developed. A new method is proposed, which takes the initial design shaft section of the worm wheel as the basic parameters and designs the diamond dressing wheel for dressing worm wheel considering parabolic tooth profile modification. The surface equations of face gear machined by grinding worm are established by two-parameter meshing equations. Tooth grinding and tooth contact analysis shows that, if a diamond wheel which directly takes the worm wheel shaft section as the tooth profile is used for dressing the worm wheel, the pressure angle of the face gear will be smaller and the transmission error curve will be discontinuous and concave. When the dressing wheel is designed with parabolic-shaped modification, the grinding surface deviation of face gear is basically negative, and the transmission error curve is continuous convex parabolic type. The loaded tooth contact analysis indicates the new design can reduce edge contact at tip of tooth and vibration. Numerical examples prove that face gears machined by this method can get higher precision and good meshing performance. An experiment is performed to verify the method.

Key words: face gear, grinding machining, grinding worm wheel, tooth surface deviation, transmission error