| With the rapid development of modern railways,the requirement for the overall performance of railway locomotives is getting higher.At the same time,the requirements for the dynamic stability and safety of gear transmission system are higher.Since the locomotive gear transmission box is a bridge between the locomotive traction motor and the wheel pair,the transmission performance of the locomotive directly affects the running performance of the locomotive.In order to reduce the inertia force of locomotive at high speed and increase the stability of gearbox transmission,an accurate calculation method of time-varying meshing stiffness is studied for webbed spur cylindrical gear transmission in the railway locomotives.And the multi-objective optimization method was used to optimized the gear structure so that the stability of locomotive running is ensured under the condition of reducing the mass of the locomotive gear transmission system.The main contents of this paper are as follows:1.For webbed spur cylindrical gear transmission in the railway locomotives,this paper proposes a calculation method of meshing stiffness based on the principle of strain energy.The influence of web and rim thickness,the radius and number of the hole in web on the meshing stiffness is analyzed and the change rule of the meshing stiffness is obtained for the webbed spur cylindrical gear transmission.2.By using the lumped mass method and the meshing stiffness calculation method,the spur cylindrical gear transmission dynamics model considering time-varying meshing stiffness and gear backlash is established.The four-step Runge-Kutta method is used to solve the three-degree-of-freedom spur cylindrical gear transmission system.The bifurcation diagram,phase diagram and Poincare section diagram of the system are analyzed by numerical calculation method,and the structural parameters affecting the dynamic behavior of webbed spur cylindrical gear transmission system of locomotive are analyzed.3.According to the effect of structural parameters on gear dynamic characteristics,the multi-objective genetic algorithm was used to optimize the webbed gear structure with the objective for the minimum of the mesh stiffness fluctuation factor and the mass of the webbed spur cylindrical gear.The frequency-response characteristic of the webbed spur cylindrical gear transmission under different operating speeds were compared and analyzed before and after optimization.The results show that the meshing stiffness calculation method proposed in this paper can be used to calculate the meshing stiffness of webbed spur cylindrical gears accurately and the variation of web structure parameters can cause the large change of ge ar meshing stiffness.Through the optimization of locomotive webbed spur cylindrical gear,the dynamic error of the gear transmission system can be reduced while the mass of the locomotive gear transmission system can be reduced,so that the gear system has better transmission stability. |
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