Abstract:In order to further improve shifting quality and system robustness of automated manual transmission (AMT), an AMT system program based on direct-drive and self-energizing shifting system is given. These technical measures can improve the compactness of the system and the shift quality of AMT, at the same time, the shifting energy loss happening in the process of gear switching is reduced greatly. The key technologies of shift system based on direct-drive technology are researched by theoretical analysis, simulation and experiment in this thesis. The structure of direct-drive device is designed, and then, the performance tests have been completed. To solve the inherent problems of direct-drive technology, a servo synchronizer with the function of self-energizing and improving the shifting system robustness is studied. The principle prototype of self-energizing shifting system is developed reference to real vehicle parameters. The universal test bench for AMT shift system based on 2-DOF EMA has been constructed. The feasibility, functionality and versatility of AMT shift system based on direct drive technology are verified in the last. The results show that the maximum instantaneous force provided by self-energizing shifting system is smaller than traditional shifting system in the same shifting quality, and the shifting energy loss can be reduced greatly. The force amplification coefficient nF is nearly 1.54 when the energizing bevel angle θis equal to 116°. For the direct-drive automated mechanical transmission, the upshift time is controlled in nearly 150ms and the synchronization time is controlled at 105ms when the rotary speed difference is 500r/min, the moment of inertia is 0.04kg·m2 and the maximum instantaneous force reaches 770N. At this moment, the maximum instantaneous force provided by shift driving device of direct-drive and self-energizing shift system is 500N, it has been reduced nearly 35%. Thus, the functions of amplifying force output by driving device and improving the shifting system robustness are implemented. It has laid a good technical foundation for decreasing the volume of driving device and reducing the difficulty of shifting control system design.