Research On Modification Method Of Tooth Profile Of Involute Cylindrical Gear

Involute cylindrical gears are widely used in mechanical transmission for the reason that it has such outstanding advantages in passing movement performance, mature processing technology and simple processing cutting tools. However, the contact elastic deformation, thermal deformation existed in the process of gears tooth and inevitable errors produced in manufacturing lead the negative effects of meshing shock, vibrations and noises which have a negative effect in transmission smoothness. If only improving the manufacturing accuracy and installation accuracy to raise the transmission performance, the manufacturing cost will increase sharply. A lot of theoretical research and practice have proved that the proper modification of gears tooth profile can improve the gears operation performance and its carrying capacity effectively.In this thesis,it takes digestion studies for automotive transmission gears transmission system and puts forward a method of tooth profile modification design to provide technical support for the developed transmission which works under the condition of high speed and overloaded operation. According to the principle of gears meshing, it established 3D parametric finite element analysis gears model in ABAQUS. It also uses the dynamic contact algorithm to analyzed the contact load in the process of gears meshing. On the basis of the combination of conjugate meshing gears principle, it comes up with tooth profile modification scheme based on power function. In this process, the author’s main tasks are as followed:It Analyzed load distribution rules in the process of gears meshing transmission from the perspectives of the gears meshing transmission characteristics and demonstrates theoretically the feasibility of gears modification in view of load mutation caused by the changes of the meshing gears in the transmission. Besides, it summarizes the existing gears modification technology research, focusing on the three elements of modification(modification curve, maximum profiling quantity and profiling length).Generalizing the commonly used determines of maximum profiling quantity and profiling length. It also introduces the common modification curves and its applicable occasions.(2) The node coordinates calculation formulas of tooth profile curve of standard gears were deduced in detail.In this paper,it also discusses the geometric location of tooth involute profile and tooth root transition curve. On this basis, it raises the method of tooth profile modification based on power function and derives the nodes coordinates of modification curve as well as the method of calculating the modification coefficient.(3) It sets up 3D model of standard gears and modification gears based on power function.The relationship between MATLAB and core of ABAQUS was established by the medium of text files.In the paper,it also introduces the process of finite element model of gears dynamic contact analysis in ABAQUS. Taking the maximum Mises stress in different meshing position as an indicator to evaluate the modification effect. For the reason that many random factors influenced the maximum profiling quantity and profiling length, it takes improved response surfaces method to optimize modification parameters, the converged points were best modification parameters combinations of modification gears.The results show that the modification gears based on power function can reduce the maximum Mises stress of tooth surface contact area effectively and improve the stability of vehicle transmission. Therefore, the study of tooth profile modification has a great significance on transmission performance and comprehensive tooth modification...