Design And Dynamics Analysis Of The Chain CVT Drive System For A Tractor

In recent years, with the development of technology and craft, the CVTs are more and more widely used in various types of vehicles. As a kind of the CVTs, the chain CVT with its unique chain structure breaks through the high torque limit of the traditional steel belt type CVT, and make it is possible for CVT used in vehicles with high torque. This paper was supported by the enterprise commissioned technology development project "The Development of Chain Simulation Technology ", and collaborated with Hangzhou Donghua Chain Group. This paper designed a chain CVT transmission device for a tractor and researched the relevant characteristic with CAE analysis method. The research establish the design and analysis evaluation method of chain CVT.The paper summarized the domestic and foreign research status of chain CVT, and compared with the different configurations of CVT. The main structure and transmission principle of the chain CVT were introduced in detail. The geometry relationship of the chain CVT transmission device was specifically analyzed. The related parameters was determined, and the mechanics model was established. The mechanical relationship such as the contact force between roller pin and pulley, the clamping force of the pulley, the thrust ratio were analyzed.According to the basic parameters that the enterprise providing such as input torque and transmission ratio and the requirements of the transmission system overall size and layout, the paper designed a chain CVT transmission device for a tractor. The design and selection principles of every parts and components were detailed illustrated. Based on the use of the special chain shape and pitch, a kind of assembly method which both can relieve the chain weight and does not affect the strength was innovative put forward. The geometric modeling of chain CVT transmission device was completed in CATIA software.The paper analyzed the strength and stiffness of the roller chain and pulley with the finite element analysis and the analysis results showed that the strength and stiffness of the chain and pulley used in the design meet the requirement. In addition, based on the theory of the finite element modal, the modal analysis of the transmission device was conducted, the frequency and shapes were calculated. The results showed that the device meet the requirement of vibration characteristic.According to the multibody dynamics theory, a dynamic analysis model of chain CVT was established by ADAMS software. The dynamic characteristics were researched under the different input speed and different ratio. The analysis data included the output speed, the labeled link running track, the tension force and the clamping force. The analysis results showed that the dynamic characteristics of the chain CVT transmission system consistent with theoretical analysis.The research results of this paper provides a basic method and thought in designing and analyzing the chain CVT for vehicle transmission system and other chain transmission system. And it is important for enhancing the independent development ability of the chain CVT system.