Parametric Design Of Hob Tooth Profile And Optimization Of Protuberance Parameters Affecting TIF

The application of large torque engine and high speed motor brought by the development of automobile power technology,as well as consumers’ increasingly demanding demand for ride comfort,put forward higher requirements for automobile transmission system.It is required that the transmission system must not only meet higher bearing capacity,but also have good NVH performance.The "fine high tooth" gear with reduced modulus and pressure angle and increased addendum height coefficient can meet this requirement to a certain extent.However,this design poses a new challenge to gear machining,that is,the true involute form of gear profile is difficult to be guaranteed.When the diameter of the circle where TIF is located is larger than the diameter of the circle where start of active profile is located,it will lead to unstable gear meshing and loss of NVH performance.In this paper,the tolerance between TIF and SAP is ensured through the optimal design of hob tooth profile,and the existing process is further improved to improve the TIF machining accuracy of "fine high tooth" gear.The main work includes:(1)Parametric design of hob tooth profile and TIF solution.Taking the protuberance chamfer tooth profile as the model,the protuberance parameters and TIF solution logic are proposed,the parameter equation of tooth profile is established,and the parameters of each tooth profile are deduced.Based on the gear meshing principle,the meshing equation between hob and gear is determined.Through coordinate transformation,the conjugate curve parameter equation corresponding to each curve segment of hob tooth profile is solved,and the TIF diameter is solved by equal radius method.(2)Analysis and optimization of tooth profile parameters affecting TIF.The influence of tooth profile parameters on the diameter of the circle where TIF is located is analyzed by using the TIF solution model.The results show that the amount of protuberance parameters in the parameters of tooth profile protuberance and stock allowance on both sides have a significant influence on TIF.Furthermore,the tolerance function between TIF and SAP is established,and the optimization logic of protuberance parameters is proposed.(3)Based on VB.NET system platform development.By analyzing the actual needs of an enterprise,combining with My Sql database technology and.Net platform to build a modular system platform with gear transmission design function.The "hobdesign" module with the functions of parametric design of hob tooth profile and optimization of protuberance parameters is designed in detail.(4)Hob design and process improvement.Taking the DCT 7 gears of a certain enterprise as the application object,the protuberance parameters of the original machining hob are optimized by using the system developed in this paper,and the dressing technology of worm grinding wheel in the grinding process is improved.Through the actual measurement and the actual measurement on the off-line test bench,the TIF of the optimized finished gear meets the design requirements and the NVH performance is good,which shows the effectiveness of the design optimization method and process improvement method proposed in this paper.