Research On Reverse Solution Of Worm Gear Surface And Digital Manufacturing

The special characteristics of the worm drive meshing,the transmission process is easy to cause the worm wheel pitting,wear and gluing failure forms.For some cases where the accessories and the unknown worm gear design parameters cannot be supplemented,it is necessary to quickly and accurately adapt the failed worm gear.With the continuous development of CNC machining technology,the use of CNC machining with higher processing quality and flexible processing methods is the trend of small batch processing.The worm sub-point cloud acquisition is performed by using the Tianyuan photo-type 3D scanner OKIO-B-400 device.Two kinds of worm gear models were compared and analyzed by the point cloud reverse reconstruction method and the simulated worm gear hob machining process.Using Imageware to align,segment,and simplify the point cloud,the tooth surface is reconstructed by two methods: curve reconstruction surface and point cloud directly fitting the surface.Based on the deviation of the point cloud and the surface and the smoothness of the surface,the merits and demerits of the two fitting methods are judged.By contrast analysis,it can be found that the method of reconstructing the curved surface is better.The method of curve fitting the surface is used to obtain the curved surface of the worm wheel,and the three-dimensional model of the worm wheel is completed in UG.The same method is used to construct the three-dimensional model of the worm.According to the three-dimensional model of the worm,some parameters were modified to obtain the model of the worm wheel hob.In the UG,the VB program is used to control the worm wheel hob model,and the process of automatically simulating the worm wheel blank for machining the worm wheel blank is realized,and the worm wheel model which is enveloped by the worm wheel hob is obtained.In the dynamic simulation software RecurDyn,a virtual prototype model is established for the worm pairs assembled by the worm gears created by the two methods.The simulation analysis of the transmission error and contact force of the worm pair is carried out under two different working conditions.It can be found that the worm gear consisting of the worm wheel obtained by the point cloud reversely has a smaller fluctuation amplitude and contact force value of the worm gear transmission error under two working conditions,but the transmission error and the contact force fluctuation value are larger.Using the processing module of UG,the NC machining code of the rough machining,the semi-finishing milling and the finishing milling of the worm wheel obtained by the point cloud is planned,and the NC program code of the worm wheel numerical control machining is output through the post-processor.The machine tool model of worm gear machining is built in VERICUT,and the actual machining process of the simulated worm gear is simulated to verify the NC machining program of the worm gear.The actual machining of the worm wheel is completed by a 3-axis CNC machine tool,and the original worm gear and the reverse worm wheel are respectively subjected to the rolling inspection test on the modified lathe.The contact impressions of the two are basically the same,which verifies the feasibility of the worm wheel model method obtained by the point cloud.