Parametric Modeling And Contact Analysis Of Involute Cylindrical Gear

Gear transmission has the characteristics of high efficiency,stable transmission ratio and reliable performance.It is one of the most important transmission forms in mechanical transmission,and involute cylindrical gear stands out with its simple structure and good applicability.The optimization and design of the traditional gear is based on the design ideas summarized from the theory of material mechanics,mechanical principle and long-term summarized practical design experience.In the design process,a large number of simplifications are carried out,and it is difficult to accurately judge the design results.With the application and development of CAE and CAD technology,more and more scholars at home and abroad use simulation technology to analyze the process of gear meshing transmission,which effectively overcomes the defects brought by traditional design methods and provides technical guarantee for the optimization design of gear transmission.Solid modeling is the premise and foundation of gear transmission meshing simulation.In order to accurately simulate the process of gear meshing,the real model of gear transmission must be established.Compared with general mechanical parts,the tooth profile of gear tooth surface is more complex,and it is difficult to establish a real gear model of tooth surface.At present,there are mainly two commonly used methods : one is to derive the gear tooth profile equation by using the gear meshing principle,so as to establish the gear model;secondly,the gear model is established by simulating the gear cutting process.In this paper,according to the first method,the involute cylindrical gear profile is established based on the equation of the tooth root transition curve,the tooth top circular arc,the involute,and the tooth root circular arc equation.After obtaining the gear profile lattice,the gear model is omitted from the point to the surface,and from the surface to the body.Then,the mesh is divided by the commercial software,and finally the step to the point is obtained.The mesh of the gear is directly divided by the node coordinate points of the gear model.After obtaining the gear profile,in order to adapt to the division rule of the transfinite mapping method,the gear tooth profile is divided into certain regions.By decomposing the complex domain into simple subdomains,the local quadrilateral mesh is divided according to the transfinite mapping method in the subdomains,and the complete gear mesh is obtained by sweeping the mesh.After meshing,the gear coordinate nodes are numbered according to ABAQUS mesh numbering rules to generate the whole gear mesh model.After Qt as a platform,through C ++ language with Open GL tools,finally generated the involute cylindrical gear parametric modeling software.Gear finite element mesh inp file information can be generated by inputting gear parameters and mesh density information in the modeling software.As a domestic independent research and development of CAE software,LiToSim has a powerful pre-post processing module and solid mechanics solver.By embedding the involute cylindrical gear parametric modeling program into the domestic software LiToSim,the LiToSim component library function is created to facilitate engineers to quickly establish the hexahedral mesh model of standard parts.In order to verify the effectiveness and high fidelity of the involute cylindrical gear model,the contact pressure of gear tooth surface is calculated according to the calculation method of the national standard GB/T 3480-1997 involute cylindrical gear carrying capacity.The gear transmission meshing process is simulated by ABAQUS and LiToSim software,which proves the accuracy of the gear mesh model,the authenticity of the LiToSim solution and the feasibility of the LiToSim component library.Finally,four factors affecting the meshing simulation analysis of involute cylindrical gears are studied.Taking five groups of different gear pairs as examples,the static contact analysis of the gear is carried out by changing the grid density,tooth width,friction coefficient and stiffness coefficient.The contact stress and contact pressure on the tooth surface of the gear,and the bending stress of the tooth root of the driving gear and the driven gear are calculated by ABAQUS software.The calculation results are collated and analyzed by tables and curves.The following conclusions can be obtained by comparing the calculation results :adopting the method of encrypting the grid and simplifying the tooth width is a feasible method for calculating the contact stress and contact pressure of the gear.The friction coefficient has a great influence on the gear meshing analysis results,so it should be carefully selected.The selection of stiffness coefficient has little effect on the calculation results.According to the simulation results in this paper,the stiffness coefficient of 3 is more appropriate.