The Research Of Auto Transmission Gear Meshing

Transmission, as the critical composition of a car, is the hub of power transmission and the core of controlling the speed change. Gear, being the core component of the transmission, always works in the condition with ever changing speed and work load. The impact upon tooth surface of gear causes the damage to gear, especially of tooth surface. Therefore, the study of transmission gear is of particular importance.This paper makes a profound research on transmission gear model building. First of all, the paper briefly describes the features of model building and dynamic simulation by using UG, builds a three-dimensional model of the transmission gear train, and does a detailed modeling study on the predominant transmission part named cylindrical gear. Besides, the paper summarizes the current modeling methods of gear, figures out the corresponding disadvantages and shortages, and explores a feasible parametric modeling method of transmission helical gear, providing a more efficient way for building model of the transmission part. The virtual assembly process and the analysis of motion simulation in UG software shows that the three-dimensional model built in the proposed method, which has no interference surface, meets the requirements of interference check. The correctness of the model is also clarified by both theoretical calculation and experimental demonstration.Second, the paper offers a brief overview of virtual prototype technology and simply introduces ADAMS, the software of virtual prototype technology. Based on the feasibility of data exchange between ADAMS and UG, the paper imports the well-established three-dimensional model of the transmission part into ADAMS, sets up the pair, the drive and the parameters of gear collision contact and then makes the dynamic simulation analysis. The results of the research are basically consistent with the theoretical numerical values. And the paper develops a dynamics model of two pairs of gears of five-speed which are meshing simultaneously, makes the dynamic simulation analysis and conducts a contrast analysis on the differences of each gear meshing force between the situation that two pairs of gears are meshing simultaneously and the situation that only one pair is meshing. In the next place, brief statements on the gearing mesh collision contact theory. With the method of time variable step length calculation based on ADAMS,the paper makes a detailed analysis of collision contact parameters such as stiffness coefficient, collision index, the maximum damping coefficient and penetraction depth in the collision contact function in ADAMS. Consequently, the regular pattern of the influence on each engaging force of the gear was summed up and a more simplified research method was proposed in the paper. Meanwhile, the research shows that simulation parameters’step length and the integration scheme, to some extent, have an influence on the analysis of the gearing mesh collision contact. The paper solves the simulation models according to the different solvers obtained from the changing simulation step numbers and integration schemes.Finally, based on the geometric model of the five-speed transmission gear and virtual prototype technology, with the different selected alignment errors, the paper analyses the influences upon gear meshing movement of different erection errors and comes to the transmission rule of transmission gear meshing movement.