Dynamic Model And Simulation Of Cold Ring-rolling Mill

Cold ring rolling is a high-efficiency metal plastic forming technology for manufacturing seamless rings, which is widely employed in many industrial fields of machinery, automobile, metallurgy, chemical engineering, energy sources, aeronautics and so on. Ring rolling mill is the indispensable equipment for ring rolling production, as well as the working parameters are the core references for mill design. The cold ring rolling mill should not only have satisfied kinematical performance, but also good dynamic drive and control performance in order to produce high-quality ring in high efficiency. However, being lake of accurate theoretical criterions for cold ring rolling mill design, the hypothesis-based energetic parameters and kinematic parameters have deviation to the actual operation performance, the adaptability to the changes of material characteristics and ring dimension are also need to be improved.The ring rolling principle, advantages, the existing problems and the future development were introduced in the thesis, also the mechanical structure and operation principles of cold ring rolling mill were analyzed, and the kinematical & dynamic mathematical model were established;the mechanical component structure were analyzed and the machine CAD models were made, which were used to built the Virtual Prototype by defining the kinematical constrains and original movement drive to achieve the kinematical and dynamic simulation analysis to the cold ring rolling mill. The achievements and conclusions are as follows:Kinematical theoretical analysis and computer simulation were made to the ring rolling system, the kinematical equations of the sliding block's linear feeding motion, ring's rolling motion (including ring's diameter expanding motion, ring's rotary motion and linear motion) and guide roller's motion were derived, the kinematical rules of ring rolling mill were researched. By the comparison between the cylinder-fixed guide system and cylinder-swing guide system, the conclusion was made that the cylinder-swing guide system has better kinematical performances and is easier to accomplish higher control accuracy.Based on the ring rolling plastic mechanics and machine mechanics, the maindynamic constraint conditions of cold ring rolling mill were established, and the corresponding constraint parameter functions were deduced, which can be the criterions for machine design and cold ring rolling process parameters.The sliding block's feeding speed has direct influence on the cold ring rolling mill's productivity, but is constrained by the feeding stability condition. In the thesis, the dynamic analysis model of the sliding block-ball screw feeding system was established, by the analysis to the feeding stability and instability mechanism, the minimum feeding speed expression was derived, as well as the dynamic parameter expressions of the ball screw.Ring's dimension rule during ring rolling was researched, as well as the kinematical rules of the guide roller system;the calculation expression and limitation of guide force were established, the force expression and feedback coefficient of guide cylinder were derived, and firstly suggest the guide roller system's supporting force-based adjustable dynamic control strategy.The study will provide theoretical reference and criteria for cold ring rolling mill's design and control strategy as well as great guidelines in the application of ring rolling technology.