| The main function of synchronizer is to decrease abnormal impact during shifting and to achieve the correct operation of transmission as well as the drivers’ shifting comfort in MT.However in actual operation condition,synchronizer is a component with high failure rate in gearbox due to abnormal friction,lubrication and contact.Thus the nonlinear dynamics of the synchronizer as well as the lubrications of the transmission system are analyzed by simulations and experiments.The major contents of this thesis are as follws:(1)In order to investigate the detailed dynamic characteristics of the self-energizing synchronizer,a multibody dynamic model of the self-energizing synchronizer in a 14-speed manual transmission gearbox is presented.The micro-synchronization process of the self-energizing synchronizer is studied,and the dynamic force of the main components of the synchronizer is simulated finely.The model considers the complex collision process between multiple meshing teeth and the friction lubrication process between synchronous rings,taking into account the partial load of components.The influence of the geometric parameters on the synchronizing performance of the synchronizer is analyzed.The influence of the geometric parameters on the synchronizing performance of the synchronizer is analyzed.The comparison between the bench test results and the model simulation results verifies the accuracy of the model.(2)In order to investigate the stress/strain of the synchronizer components,the finite element dynamic analysis model of the self-energizing synchronizer is proposed.The parts of the manipulating system such as the clutch and the fork are included in the model.The stress concentration of the friction between the teeth is analyzed from the angle of the control system.The influence of the parameters such as the displacement of the joint,the deformation of the fork,the friction torque,the contact stress and the area on the stress concentration and the synchronous performance are analyzed,which provides support for component strength verification and performance improvement for synchronizers.(3)Since the life span of gearbox is significantly affected by lubrication,the lubricating oil model of the whole gearbox is established,and the distribution of the lubricating oil of the various parts including the synchronizer is analyzed.Optimization of the aperture of the fuel supply hole of the commercial vehicle by one-dimensional flow field model is sensitivity analyzed.Simulation and experimental results show that this method can effectively improve the rationality of the distribution of lubricating oil in each gear,which greatly improves the service life of gearbox.(4)In order to verify the dynamics and lubrication simulation results,a new synchronizer test platform is designed and manufactured,which is specifically for gearbox self-energizing synchronizers and lubricating oil paths.Aiming at the performance of the synchronizer and the flow rate of the lubrication system,a set of realistic test methods and processes are summarized to further verify the simulation and optimization results. |
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