| Fine-blanking process is a shearing process of sheet metal under three-directional compressive stress applied by a fine-blanking machine,which has the advantages of high efficiency and high precision.Fine-blanking equipment is mainly divided into hydraulic fineblanking machines and mechanical fine-blanking machines according to their power sources.Currently,hydraulic fine-blanking machines dominate the market.However,in order to improve the response speed of the hydraulic system,the hydraulic oil pump of this type of fineblanking machine always remains in operation during the working process,leading to high energy consumption and difficulty in improving efficiency.Furthermore,potential leakage problems may occur due to sealing forms and sealing material life,and the regular replacement of hydraulic oil may also pose potential pollution problems.Traditional mechanical fineblanking machines also suffer from high energy consumption,large vibration,and operating noise issues,and although they are used in small-tonnage fine-blanking machines,they have not been widely adopted for mass production in the fine-blanking industry.With the mature application of high-torque servo motor technology,it is urgent to develop fine-blanking equipment with high efficiency,high precision,and energy conservation and environmental protection by applying servo motors to the fine-blanking field.Therefore,this paper proposes a mechanical fine-blanking machine structure driven by all servo motors.The machine combines a high-torque servo motor with a toggle amplifying mechanism to drive the main cutting mechanism of the fine-blanking machine to provide cutting force,and a servo electric cylinder is used to provide the edge pressing force and reverse top force of the fineblanking process.This paper designs the main cutting mechanism and overall structure of the mechanical servo fine-blanking machine,and carries out theoretical modeling analysis and numerical simulation experiments on the main cutting mechanism,optimizing and determining the overall parameters of the machine.The main research achievements are as follows:(1)The configuration and main parameters of the main punching mechanism are the key factors that determine the motion curve of the punching slide and the effectiveness of amplifying input force in precision punching machines.After comparing and analyzing various forms of power amplification mechanisms,the combination of a screw and a rocker arm was chosen as the configuration for the main punching mechanism,and its kinematic and dynamic models were established.The optimal lengths of connecting rod 1,connecting rod 2,and swing rod were determined to be 400 mm,420mm,and 380 mm,respectively,through orthogonal experiments.The eccentricity between the drive slide and the lower hinge point was 262.5mm,and the eccentricity between the punching slide and the lower hinge point was 99 mm.According to the main parameters of the main stamping machine,combined with the selected servo motor and ball screw parameters,a virtual prototype simulation was carried out on ADAMS.The displacement,velocity,acceleration and driving torque curves of the stamping slider were obtained when the servo motor worked at rated speed under full load condition.(2)The strength of the main cutting mechanism and the frame has been verified.The maximum stress borne by the moving components of the main cutting mechanism under full load conditions is 59.627 MPa,which is far less than the yield stress of the material Q345 used for the main cutting mechanism.The maximum stress borne by the frame under full load conditions is 77.334 MPa,which is far less than the yield strength of the material Q235 a used for the frame.(3)Modal analysis was carried out on the main cutting mechanism and frame.The first six natural frequencies of the main cutting mechanism are 350.2Hz,350.45 Hz,388.39 Hz,568.48 Hz,571.26 Hz,and 599.75 Hz,which are much higher than the maximum frequency of the excitation force at 12.5Hz,avoiding resonance.The first six natural frequencies of the frame are 21.092 Hz,22.608 Hz,54.297 Hz,67.114 Hz,112.890 Hz,and 142.72 Hz,which are higher than the maximum frequency of the excitation force at 12.5Hz.Based on the punching force and frequency,it was simplified as a harmonic response impact model,and a harmonic response analysis was performed.The results show that under full load and continuous operation,the maximum deformation occurs at the servo motor installation position,with a maximum deformation value of 0.2mm and a maximum stress value of 27.6MPa,indicating that the frame theoretically will not experience significant vibration.(4)In order to reduce the weight of the main cutting mechanism and frame,topology optimization was performed on both.By optimizing the dimensions of the structures after reducing the material,the weight of the main cutting mechanism was reduced by 6.5% and the weight of the frame was reduced by 7.6%.Strength verification was conducted on the optimized main cutting mechanism and frame,showing that their strength has not been reduced.Modal analysis was performed on the optimized frame,showing that the natural frequency of the optimized frame increased by 5.292 Hz,further moving away from the excitation frequency. |
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