Machining Simulation And Experiment Of Spiral Bevel Gear Based On Four-axis NC Machining Center

Spiral bevel gears are widely used in modern industry.Because of the complex shape of tooth surface,it is necessary to process on special milling machine tool at present,which has high manufacturing threshold and poor versatility.Therefore,it is very important to expand the diversity of its processing.Based on this,this paper presents a method and strategy for machining spiral bevel gears by milling cutter head in general CNC four-axis machining center.The main research contents and conclusions are as follows:(1)A two-way hobbing method for spiral bevel gears is proposed.According to Meniere's theorem of differential geometry,the cutter disc conditions for realizing double-pass hobbing of taper are obtained;the coordinate system of spiral bevel gears for machining large and small wheels is established based on the principle of gear space meshing,and the tooth surface equation of spiral bevel gears is derived from the cutter equation of the cutter disc;Using MATLAB software to program,the initial values of the non-linear equations of tooth surface equation are iterated and solved..The obtained discrete points are imported into UG software,and the three-dimensional model of gear pair is constructed,and the contact spot simulation is carried out.(2)The method and strategy of disc-cutting spiral bevel gears in general machining centers are put forward.Based on the analysis of the structure of traditional machine tools,Free-form machine tools and general CNC machining centers,the coordinate system of machine tools is established.By using the kinematic coupling of coordinate space position,the transformation relationship and explicit expression between the adjustment parameters of bevel gear processing and the corresponding kinematic parameters of machine tools are deduced.The programming strategies and methods of spiral bevel gears machined by vertical four-axle blank inclination and horizontal four-axle cutter head angle transformation are determined,and the NC machining strategy of chamfering flange on the top of large wheel teeth and the construction method of transition surface model are put forward.(3)The feasibility of cutting spiral bevel gear with cutter disc of CNC machining center is verified by simulation and cutting test.The physical motion models of vertical and horizontal machine tools are established by using VERICUT software,and the corresponding NC processing program is compiled to simulate the cutting of largeand small spiral bevel gears respectively.The simulation results are consistent with the design model generated by the theoretical tooth surface equation.On a four-axis machining center,the large wheel is cut by double-sided method and the small wheel is cut by taper double-pass hobbing method.Finally,the tooth surface contact spot hobbing test and the tooth surface deviation topological measurement are carried out.The quality of the contact spot and the tooth surface accuracy of the cut gear meet the requirements.The research results have achieved the expected goal and laid a foundation for flexible manufacturing of complex spiral bevel gears based on CNC machining center.