Design And Dynamics Simulation Analysis Of Transmission System Of Chain CVT

With the increasingly serious energy crisis and global warming problems,fueled by regulatory and market forces,fuel vehicles are facing stricter fuel consumption and emission standards,and the government is strongly supporting the development of hybrid and electric vehicles.Compared with other transmissions,the continuously variable transmission has a larger transmission ratio range,and CVT has the advantages of simple operation,fast response and no power interruption when shifting gears.Therefore it has huge application potential.But now there is no systematic design and analysis method for rocker-pin chain continuously variable transmission in China.In this context,the thesis makes in-depth research on the dynamic characteristics and power loss of the continuously variable transmission.This article first briefly introduced the development process and research status of CVT,Subsequently,the transmission mechanism of the rocker-pin chain CVT,the variable pitch characteristic of the rocker-pin chain and the cause of polygon effect in the chain transmission system were explained in detail.Next,according to the parameters of the pins and chain provided by the partner company,Built 3D solid model of CVT,then established the dynamic model of chain CVT using Recurdyn.The dynamic simulation analysis of the chain CVT transmission system was performed at different speeds and transmission ratios,then compared and analyzed the chain tension,the contact force between pins and cones,the longitudinal trajectory of the marked chain link,And summarized its changes and analyzed the reasons,The results showed that under different operating conditions,the dynamics and movement characteristics of the chain CVT were consistent with theoretical analysis.And the stability of the model was further verified by multi-body dynamics simulation under the change of speed ratio.The rigid-flexible coupling analysis of the chain was carried out,the maximum stress value and the position where the maximum stress value of the chain during the transmission cycle were obtained.Built a complete vehicle transmission system model in AMESim and carryed out co-simulation of AMESim and Recurdyn.Firstly,the changes of chain tension and contact force between pins and cones under different torques were analyzed.Then the output curve fluctuation characteristics,torque loss,slip and transmission efficiency in the chain CVT under different operating conditions were studied in depth.Further understood the impact of different input conditions on the dynamic characteristics of the chain CVT and the specific loss of transmission power.The change law was similar to the theoretical analysis result,The feasibility of the chain CVT design scheme was proved.In this paper,the dynamic characteristics and power loss of a chain CVT transmission system under different operating conditions are studied.It was of great significance to understand the impact of the chain CVT's vibration shock,meshing shock and longitudinal fluctuation of rocker-pin chain on the system during the movement.It also provided an important basis for the structural optimization and improvement of chain CVT.