Dimensional Optimization Of Offset Six Bar Mechanism Of Mechanical Press Used In Deep Drawing Process And Virtual Prototype Design

Mechanical press is the main equipment for forging production,which affects the forming quality and efficiency of the forging products.With the continuous improvement of manufacturing level,especially the development of the automotive industry,the quality and efficiency requirements of the forging products are getting higher and higher.Therefore,the combination of multi bar mechanism and servo driven technology is an important means to improve the working performance of the press and obtain high quality forging products.In this paper,a servo driven six bar mechanism drawing forming press is taken as the object,and the key technical problems such as the configuration of the mechanism,the side force of the slider,and the optimization of the rod system are studied.The virtual prototype model is built to analyze the working state and performance of the press,and to provide the design basis for the design and manufacture of the related press.Using simulation software,the rod configuration and bar dimension on dynamic performance was studied,and comparing the different effects of slide offset(negative bias,positive and positive offset)and the arrangement of triangular bars(inverted and positive)on the motion performance,partial load and slider lateral force of the press.Subsequently,the transmission mechanism configuration of traditional press was compared to the six bar mechanism drawing forming press.The analysis results show that the structure of the six bar structure with triangle rod inverted slider and negative offset is more suitable for the design requirements of the drawing press.According to the two arrangements of the triangular rod and the offset of the slider,the appropriate parameters were used to establish the unified kinematics equation,which lays the foundations for the truss optimization design.The influence of pressure motor load(inertia force and inertia force moment)and self–weight were considered.The force condition of slide block and connecting rod in process stroke were analyzed.Finally,the theoretical formula of side force acting on slide block was completed.The angular acceleration affects the lateral force of the slider wasanalyzed.It can be obtained that with the increase of angular acceleration,the lateral force of the slider increases.On the basis of meeting the kinematics requirements,the rod dimension of a drawing press for a 200 kN six bar mechanism with a stroke of 190 mm was optimized according to the optimization method of the minimum force and the maximum height of the stroke,the size of the optimized crank rod was about 40 mm.According to the optimized rod dimension,and considering the characteristics and performance requirements of the press,the power and design of the motor are selected and the transmission ratio of gear reduction mechanism is selected,finally,the model of the virtual prototype of the press machine is established.The Virtual Prototype Technology is used to simulate and analyze the size of the optimized rod structure by dynamic simulation software.The simulation results show that the kinematics and mechanical properties of the design press are better.The influence of balance force and the interstitial clearance on the dynamic performance of the press was analyzed,and it can be obtained that the best balance is 3kN and the sliding side clearance has the greatest influence on the lateral force of the slider.The finite element analysis software was used to analyze the deep drawing forming press for the static strength.