| This research was sponsored by National Science and Technology Major Projects Large and High-accuracy CNC Forming Wheel Grinding Machine(No.2014ZX04001).In the forming grinding of large gear,the machining error of machine tool can cause the gear accuracy to be reduced significantly.In order to improve the status,this thesis can study the effect of machining errors on gear errors by using mathematical analysis and machining error simulation method,which provides reference value for improving the machining precision of CNC forming wheel grinding machine and the prophase design of machine tool.The main research contents are as follows:Based on the kinematics theory of the multi-body system,the geometrical error model of the linear and rotational axes of the forming wheel grinding machine is established by using the homogeneous coordinate transformation matrix,and the topological structure of the machine tool is described by the low sequence array.This thesis expounds the ideal and actual motion transformation matrix between adjacent bodies of the machine tool,and establishes the ideal and actual motion model between grinding wheel and gear and the spatial geometrical error model.This thesis can analyse the shape forming process of the forming wheel grinding machine,and present the motion creation method.The influence of grinding wheel position deviation on tooth profile error,pitch error and common normal length deviation in gear forming grinding is studied by mathematical analytic method,and the influence of gear mounting error on tooth profile error and pitch error is analyzed.The results show that the influence of the grinding wheel radial position deviation on tooth profile error and the pitch error is greater than the tangential one,and the influence factors of the difficulty degree of grinding the few teeth gears and the relation between the cumulative deviation of the tooth pitch and the eccentricity.Based on VERICUT machining simulation software,this thesis constructs the machining system of virtual CNC forming wheel grinding machine,and simulate the machining of gear forming grinding.The influence of grinding wheel position deviation and gear mounting error on gear accuracy is studied qualitatively by machining error simulation method.It measures the positioning error and straightness error of machine tool by using the laser interferometer.According to the geometric error distribution law,the geometric error data of the simulation machining is simulated,and the effect of Z axis geometric error on the tooth error is studied by using the single factor variable method.The results show that the tangential straightness error has the most obvious influence on the total helix deviation during the forming grinding,and its radial straightness error has obvious influence,and the positioning error has no effect.The conclusion of the single factor variable method is validated by the multi-factor variable method,and the gear precision can be improved by the proper straightness error coupling.The error compensation method is used to improve the motion accuracy of the milling machine tool’s linear axis. |
