Research On Gear Profile Modification And The Optimization Design For Gear Box Of High-speed Train Drive System

Gear transmission system is one of the important mechanical transmissions, which applys in industrial and life in each area. In the railway sector, with the rapid development of high iron, the high speed of the train have very high demands for the gears transmission and the stability of the gear strength requirement and its life. Our country has the certain independent research and development technology in high iron field, but in the poor conditions, how to use accurate gear repair design to improve gear transmission precision, to improve the bearing capacity, to reduce the contact force on gear surface, to prolong its life, is one of the difficulties in the field of high iron. With the rapid development of high iron, the high iron gear box have very high demands for the structure of the fatigue strength, so it makes great significance for optimizing the structure of high iron gear box. Combining with the state support plan applied by Dalian university of technology and the Qi shuyan institute cooperation of CSR, this paper puts forward a set of methods for designing tooth profile of iron helical gears, the parameters calculation of tooth profile shape is done through combining the theory and simulation methods, the authentication of design results is done with dynamic simulation software DYNA, finally the structure optimization design of high iron gear box is done, which has great significance for the design and manufacture of high iron gears and the iron gear box. Specific content is following:First of all, gear model is established and contact finite element model is analysised before the safety factor of the inclined gear is calculated, and contact strength and bending safety factor achieve high reliability requirements in the four cases. Based on the analysis, the gear needs to be formed. the causes of gear meshing impact and the three concept of tooth profile modification is introduced. the tooth profile margin, the length and the starting circle radius of curve shape is calculated by using the theory and finite element method,and tooth profile form curve is designed in the MATALAB software, on which gear models are built in UG. Based on the theory of elastic, contact method is used on the proposed finite element models of gears by software LS-DYNA, and the effect of relief curve on three concept of tooth profile modification is analyzed. The results shows that the contact force of teeth face is the smallest and the relief effect is the best while the relief curve is conic and sine curve, The maximum contacting force is6865N, which reduced30%than non-shape while modification parameters is0.027mm and relief length is3.5mm. The results shows that the effect of single gears relief is better than double modification. Therefore, it makes sense to transmission gear box in high iron.Finally the modal analysis of the overall gear box is done and the ten modes of gear box, the inherent frequency, and the deformation of gear box is obtained. And further the dynamics analysis on gear box shell is done, and according to the results of above analysis,the structure of gear box shell is improving designed. And then the improved structure is analysised, the results show that the deformation of the improved model is less than the model before, which prove the scientific nature of the optimization scheme.