Meshing Simulation Analysis Of The Carburized Cylindrical Gear Pair

Carburized gears are widely used in various fields due to their strong bearing capacity on the surface and their good plasticity and toughness in heart.The carbon concentration at each point of the carburized part is different after carburizing,which makes the material nonlinear.However,the traditional contact strength calculation method still treats the gear carburized surface as linear material,resulting in an error for calculation result,and using formulas to calculate the carburized gear strength cannot obtain stress intensity value at any point on the meshing tooth surface.Based on this,this paper proposed a method of modeling the carburizing part into multi-layered homogenous layers,and used the finite element analysis method to simulate the meshing performance of carburized gears.In order to simulate the nonlinear material properties of carburized gears,this paper proposed a method of modeling the carburized part into multilayered homogeneous layers.First,the tooth profile surface was obtained based on the bicubic B-spline surface,and the tooth profile surface was used as basis,and then using surface offset to achieve the stratification of carburizing section.Generally,the more homogeneous layers,the more accurate the model,but too many layers will increase the difficulty of modeling.A first offset surface was obtained by offsetting the tooth profile surface to the thickness of homogenous layer along negative normal direction.The tooth profile surface and the offset surface enclose the first homogeneous carburized layer.On the basis of the first offset surface,the second homogeneous carburizing layer was generated.By analogy,the approximate model of the carburizing part of the gear was obtained,which lays the foundation for the analysis of the later transient meshing simulation.The meshing process of gears was analyzed by transient meshing analysis based on ANSYS.The simplified finite element model of carburized gear pair was created based on carburized layer.The transient meshing characteristics were analyzed to obtain the stress distribution at any time and location of tooth surface and root.At the same time,the path mapping method can be used along the gear carburizing direction to study the variety trend of the shear stress of gears.Compared with the stratified modeling method,it can be found that the shear stress variety trend with the modeling method proposed in this paper increased firstly and then decreased,and the shear stress variety trend without stratification was gradually reduced along carburizing direction.The worst contact position,bending positions,and shear position of the carburized gear pair can also be obtained by transient analysis,which can provide the basis for subsequent static contact and fatigue analysis.In order to obtain more accurate analysis results,the full tooth model of carburized gear pair was set up.Static contact analysis was carried out at the worst meshing positions obtained by transient analysis.The maximum contact and shear stress of the gear pair,the maximum bending stress of the drive and driving wheels were obtained,and the results of the finite element analysis were compared with those calculated by traditional method.The key to study the fatigue performance of carburized gear pair is the determination of load spectrum and S-N(stress-life)curve.The stress results obtained from transient analysis were used as the load spectrum of fatigue analysis.The S-N curve was obtained according to the gear material,and the gear pair was placed to the worst contact,bending,and shear meshing positions based on the Workbench for fatigue analysis.The contact fatigue,shear and bending fatigue life and safety factor distribution of the gear pair were obtained,which can provide a basis for further checking and optimizing of gears.