The Research On The Optimization Of The Manual Transmission System And The Evaluation Of The Gear Shift Quality

The manual transmission still takes up a large market presently, therefore the further research on the optimization of the manual transmission system and the evaluation of the gear shift quality is of great significance to the consumer, the vehicle factories and the manufacturers of the manual transmission as well.Taking the minivan’s shift operating mechanism as the research object, the thesis analyzes the comfort level of the driver’s sitting postures and the driving comfort level based on the principle of ergonomics, and the thesis also compares the sitting postures comfort level and the driving comfort level between the original vehicle and the improved vehicle. In the research, the optimal model of the shift operating mechanism has been established through the kinematic analysis and statics analysis of the shift operating mechanism. And based on the NSGA-Ⅱ, software programming has been undertaken on the MATLAB platform. Then this software program is used to optimize the mathematical model of the shift operating mechanism. The comparison of the data shows that the result of optimization has achieved the set objectives.The thesis has analyzed the construction of the manual transmission, set up the mathematical model of the manual transmission gears, chosen the relevant constraint conditions by use of the designing method of mechanical reliability, and carried out the optimal designing on the manual transmission gears in the MATLAB, based on the calculating method of NSGA-Ⅱ. Then a group of optimal data is picked out and compared with the original data of the gears. The result demonstrates that the optimal objectives have been improved in various degrees.The thesis has developed the manual transmission comprehensive performance testing system, which can undertake the tests of the gear shift performance, the clutch performance, and the synchronizer performance. Based on the Virtual instrument technology and by means of a series of sensors、motion control card、data acquisition card and some concerning equipments, the testing system writes the software of data acquisition module signal processing、stepped motor controlling、graphical display、 data storage and so on, which enables the manual transmission performance testing system to accomplish the operations of data sampling, transportation and saving, processing and dynamic displaying automatically by use of the Lab VIEW software developing platform. According to the concerning criteria, the thesis has a research on the test of the gear shift performance of the manual transmission. Take into consideration of the timing of gear shift when the vehicle running on the road, the thesis formulates the rotational speed controlling scheme of the variable frequency motor on the testing bench. The thesis designs the rotational speed of the transmission input shaft measuring device, according to the synchronization time test plan of the manual transmission. Based on the structure of the lock ring synchronizer and its working principles, the thesis sets the test parameters and analyzes the influencing factors of the synchronization time. According to the testing result, the thesis analyzes the different stages in the synchronizing process of the lock ring synchronizer, and the changes of the testing curves.The thesis introduces the conventional concepts of the gear shift quality and the methods of evaluation on the gear shift quality, analyzes its deficiencies, and combined with the test data of the manual transmission performance testing system, perfects the evaluation indicators of the gear shift quality, based on the theory of ergonomics. According to the test data, the thesis also calculate the value of the evaluation indicators of the manual transmission, appraises it in an all-around way and evaluates the gear shift quality of the manual transmission referring to the evaluation standards.