Analysis Of The Mechanical Characteristics And Modification Optimization Of The Cross Axle Variable Thickness Helical Gear Pair

In order to improve the mechanical properties and transmission accuracy of the cross axle variable thickness helical gear,researchers at home and abroad mainly studied the parallel axle variable thickness spur gear and helical gear The strength analysis,contact analysis and fatigue life analysis of the bevel gear with variable thickness of intersecting shaft and the bevel gear with variable thickness of intersecting shaft,but the modificat ion optimization of the bevel gear with variable thickness is insufficient,because the modification of the gear can improve the stability of the gear transmission and reduce the dynamic load.Therefore,it is of great significance to study the mechanical characteristics and shape modification optimization of the variable thickness helical gear pair.In view of the establishment of the cross axis variable thickness helical gear model,the paper introduces the hypothetical profile generating rack tool,and deduces the tooth surface equation of the variable thickness helical gear from the meshing equation of the rack tool and the gear blank through the coordinate transformation of the gear cutting.The three-dimensional model of the gear is generated in the three-dimensional ug12.0 software,and then the standard installation of the cross axis variable thickness helical gear pair is carried out according to the meshing principle of the gear A complete set of cross axis variable thickness helical gear pair model.The theoretical strength of the model is analyzed to check the bending strength of the root and the contact strength of the dangerous section.The model is imported into the finite element simulation software workbench 19.0 to carry out static contact analysis,analyze the bending strength of the tooth root,and compare with the theoretical analysis results.Then the model is used to analyze the transmission contact,analyze the contact stress and transmission error,and put forward some problems for the transmission contact analysis.In the contact analysis of the cross axle variable thickness helical gear pair,two factors,backlash and time-varying meshing stiffness,are mainly considered to analyze the gear transmission problem.The function of backlas h is fitted with the 7th degree polynomial,and the nonlinear dynamic model of the cross axle variable thickness helical gear pair is constructed.Then the fourth-order Runge Kutta method is used to solve the differential equation of nonlinear dynamics for these two factors.Through the solution of these two factors,the profile modification of the variable thickness helical gear is optimized to improve the stability of the cross axle variable thickness helical gear pair transmission.In practical machinin g,the method of grinding the variable thickness helical gear with grinding wheel is adopted.In this paper,two methods are proposed for the modification of the variable thickness helical gear: one is to modify the profile with the involute angle as the independent variable;the other is to modify the profile with the involute angle as the independent variable;the other is to establish two methods for the modification of the variable profile The three-dimensional model of the non involute variable thickness helical gear pair after the modification of the thick helical gear is introduced into workbench 19.0 for transmission contact analysis,and the contact stress and transmission error after the modification of the variable thickness helical gear by two methods are solved,compared with that before the modification.