Research On Digital Simulation Of Cylindrical Gear Hobbing Process

Gear as a core mechanical foundation,its quality and performance determine the performance and reliability of the equipment.Gear industry has become the largest industry in the basic parts of machinery.Hobbing is generally used as the first step in gear machining.With the development of industrial modernization,the manufacturing quality of gears has become increasingly demanding.The machining accuracy of gears plays a key role in the performance of gears.All the errors of gear are formed in the process of machining.The error of gear is essentially the machining error.In order to improve the machining accuracy of gears,the machining process of gears must be analyzed.The purpose of the "Digital Simulation Study of Cylindrical Gear Hobbing Process" is to investigate a new hobbing simulation method and control the quality of gear manufacturing.This research provides a new way to improve the machining accuracy of gears.In this paper,starting from the principle of hobbing,the structure parameters of the hob are determined.Through the analysis of the positional relationship between the hob and the workpiece,a three-dimensional meshing simulation model of the hob and spur gear is established and hobbing is analyzed.The relationship between the angle of the middle hob and the gear is obtained by solving the intersection of the normal to the tooth surface of the gear and the involute helix of the hob to obtain the simulated tooth profile for hobbing.By comparing the simulated tooth profile with the theoretical involute tooth profile,the feasibility and correctness of the proposed method are verified.Applying the hobbing machining simulation model presented in this paper,simulation tests were conducted on the modified gears and the shaft angle error of hob installation.The main contents of this thesis are as follows:(1)Based on the coordinate system of involute helicoid and spur gear,the parameter equation of hob and spur gear is derived.Combined with the basic parameters of the hob and gear,a three-dimensional model of the involute helical surface and the spur gear tooth surface of the hob has been established,which provides the pre conditions for the study of the digital simulation of the hobbing.(2)A new digital simulation method for hobbing process of cylindrical gear is proposed.Through the coordinate transformation matrix,the gear tooth surface coordinate system is transformed into the hob coordinate system,and the gear tooth surface and the hob are combined to the spiral surface after the coordinate transformation,that is the three-dimensional meshing simulation model of the hobbing.Through the analysis of the angle relation of hob and gear in the machining process of cylindrical gear hobbing,the intersection of the involute of gear tooth surface and the involute helical surface of the hob is solved,and the simulation tooth profile of the cylindrical gear hobbing is obtained.Compared with theoretical involute profile,the error value of simulation is less than 0.5μm,which verifies the feasibility and correctness of the simulation method of hobbing.By giving two groups of basic parameters of hob and gear,it verifies the universality of the proposed digital simulation method of hobbing process.(3)Application tests were conducted on the digital simulation method of the hobbing process.Using the hobbing machining simulation model,the modified gears were simulated by increasing or decreasing the center distance of the hob and gear,and the error between the simulated tooth profile and the theoretical tooth profile was obtained.By changing the shaft angle of hob installation,a simulation test of the shaft angle error of hob installation is implemented.The comparison of the simulated tooth profile with the theoretical tooth profile shows that the existence of the shaft angle error of hob installation will result in gear tooth profile asymmetry.The error values between the simulated tooth profile and the theoretical tooth profile under the error of the cross angle of different shaft angle error of hob installation are obtained.