Fracture Analysis And Optimization Design Of Transmission Shaft Transmission Wheel

As an important part of a motor drive system,the transmission has a direct impact on dynamic performance and fuel economy,control reliability and portability,driving stability and efficiency of the vehicle.Although traditional manual transmissions have many shortcomings,such as big shift shock, bulky and manipulate complexly,they are still widely used with their high transmission efficiency and low cost.As a main part of the manual transmission,the output shaft shoulder the burden of transmitting engine power, however,due to the unreasonable design, process or assembly,failure sometimes occurs.In this paper, a two-axle and five-speed manual transmission is studied.For the fracture failure of the output shaft in the transmission assembly test before leaving the factory,the work is done to find the reason of fracture failure and optimize the design, and ultimately get the the ideal structure of the output shaft.In the paper,work is done specifically as the following aspects:(1) Aftering observing the fracture shape and fracture location, preliminary to judge that it is fatigue fracture, fracture location is axial position for the fourth output gear;(2)3D modeling software Pro/E is used to creat the three-dimensional model of the output shaft,and then the three-dimensional model is imported into the finite element analysis software ANSYS.To analysis the working conditions of the output shaft,and build the finite element model;(3) Perform static strength analysis, fatigue strength analysis and modal analysis, and then obtain a result that the fracture reason of the output shaft is fatigue failure, shoulder fillet radius is too small to produce stress concentration and lead to the final fracture failure;(4)Optimize the fillet which produce stress concentration, and then get the reasonable value of the fillet radius;(5)Perform finite element fatigue strength analysis again,then produce samples which are optimized and do the fatigue experiment to validate that the optimized structure is reasonable, finally put samples into mass production.