Research On Key Technology Of High-speed And Heavy-load Mechanical Press System

The mechanical press system is the fundamental equipment of metal forming process.The high-speed and heavy-load mechanical press system has the characteristics of high efficiency and wide range,which is employed in the industry of aerospace,automobile manufacturing and chemical metallurgical.As the development of related industries,it is an important problem that how to improve the machining accuracy and stability of high-speed and heavy-load mechanical press system,which could satisfy the requirement of stamping part.Based on the theoretical analysis and numerical simulation,this paper investigates the kinematic characteristics and dynamic response of transmission mechanism for the press system,and elastohydrodynamic behavior of supporting bearing.Furthermore,the results could provide theoretical evidence and technical assistance for the design of high-speed and heavy-load mechanical press system.The contents of this paper are as follows:The kinematics model is established based on the working principle and structural parameters,which can describe the trajectory of mechanism.Considering the inertial force of motion for high-speed and heavy-load mechanical press system,the dynamic statics model of transmission mechanism is established based on the D'Alembert's principle.Then,the mechanical analysis of the press system is studied based on this model.Furthermore,the obtained results could provide theoretical evidence for the dynamic analysis of transmission mechanism and the elastohydrodynamic analysis of the supporting bearing.In order to describe the motion trajectory of transmission mechanism with joint clearance effectively,the dynamic characteristics of traditional contact-impact force models are investigated.The effects of clearance size,restitution coefficient and initial impact velocity on the contact-impact force are studied based on the Lankarani-Nikravesh contact force model.Meanwhile,the dynamics analysis model of transmission mechanism with joint clearance for high-speed and heavy-load mechanical press system is established.The influence of revolute joint clearance on the dynamic characteristics of mechanism is investigated.The results are the theoretical basis of dynamic analysis of transmission mechanism with flexibility.Based on the investigations of the dynamic analysis for transmission mechanism with revolute joint clearance,the rigid-flexible model of transmission mechanism for high-speed and heavy-load mechanical press system is established,which takes into account the effects of linkage flexible.Meanwhile,the dynamic simulations of transmission mechanism are conducted and the results are compared with experimental data.The obtained results demonstrate that the dynamic behavior of the mechanism can be effectively predicted by this method.Then,the dynamic response of transmission mechanism is investigated by this method.Furthermore,the quantitative analysis model of dynamics response of the transmission mechanism with flexible linkage is proposed.The results can describe the effects of linkage flexible,clearance size and driving speed of crank shaft on the dynamic behavior of transmission mechanism.Considering the influence of hydrodynamic lubrication,cavitation and thermal-elastic deformation,the elastohydrodynamic analysis model of supporting bearing for the high-speed and heavy-load mechanical press system is established,which is based on the hydrodynamic lubrication equation,energy equation and cavitation equation.Then,the elastohydrodynamic simulations are conducted based on this model.And,the results can depict the effects of structural parameter of oil groove,eccentricity ratio,rotational speed and oil-film thickness on the elastohydrodynamic behavior of the supporting bearing.The manufacture and assembling of high-speed and heavy-load mechanical press system are conducted,which is based on the above investigations.Then,the experimental platform of the high-speed and heavy-load mechanical press system is set up and the performance measurements of machine are carried out.The obtained testing results describe that the performance of the high-speed and heavy-load mechanical press system can satisfy the requirements of manufacture with the features of high-efficiency,high-precision and heavy-load.And,the results demonstrate the validity of theoretical research for the key technology in high-speed and heavy-load mechanical press system.