Study On Gear Shift Smoothness Of Hydraulic Automatic Transmission

With the improvement of vehicle comfort and the development of electronic control technology,the automatic transmission adapted to modern automobile instead of manual transmission.The automatic transmission is the most widely used automatic transmission.It is the core assembly of auto control.It is directly related to the ride comfort of the vehicle.It is one of the hot and difficult problems in the development of vehicle electronic control system.In this paper,based on the analysis of the structure principle of the transmission line Allison 3500 R 6 gear automatic transmission,a mathematical model is established and the shift quality is evaluated during the transfer process.In the Advanced Modeling Environment for performing Simulation of Engineering(AMESim),the multidisciplinary field is restored.The model of the whole dynamic transmission system is set up in the software.For this purpose,the process of stepping down and loosing the accelerator pedal is simulated,the calorific value of each clutch and brake in the system is obtained,and the changes of the engine torque output,the speed of the vehicle,the speed of the vehicle and the impact degree and so on are calculated.The research contents and results provide practical reference value for the design of hydraulic transmission.The main contents of this paper are as follows:First,the typical transmission and transmission of the vehicle are analyzed,and the Allison 3500 R type 6 gear hydraulic automatic transmission is taken as an example,and its structure and power transmission line are analyzed in detail.Secondly,from the point of view of shift evaluation,3 evaluation indexes of impact,shift time and friction work are put forward,and the dynamic mathematical model of hydraulic torque converter,transmission and transmission system is established.Then,the simulation model containing engine,hydraulic automatic transmission and transmission system is built on the basis of AMESim software,and the related parameters are given.Then,the model of hydraulic automatic transmission including the full transmission system is simulated,and the shift impact,acceleration and clutch are analyzed.The influence factors of gear shift quality are analyzed,and the related tests are carried out.The influence rules of acceleration pedal depth,structural parameters of transmission and transmission system parameters on the smoothness of gear shift are obtained.Finally,the paper summarizes the achievements of the research work,and analyzes and looks forward to the further research work and direction.The research results in this paper can provide references for the design and research of hydraulic transmission.