Design Of 20KN Large Stroke Two-stage Precision Electric Cylinder Planning And Research

The electric cylinder is a precision product that combines servo motor and ball screw into mechatronics,which greatly meets the system’s precise control requirements for thrust,speed and position.It has been widely used in many civilian and military fields.The electric cylinders currently on the market are classified according to the transmission level:there are mainly single-stage electric cylinders and two-stage electric cylinders.The two-stage electric cylinder not only has the advantages of high positioning accuracy,high transmission efficiency,and good synchronization of the electrical system of the single-stage electric cylinder,but also can achieve a relatively small overall size of the electric cylinder and a relatively large stroke.Therefore,the development of a large-stroke two-stage electric cylinder provides a solution to the contradiction between the installation space(small installation distance)and the working stroke(large stroke)in practical applications,which has important engineering value.In this thesis,the electric cylinder with a 20KN ultra-long stroke and a large radial load is taken as the research object.The main research content is the structural design of the electric cylinder,the simulation of the operating process,the stress analysis of the key components,and the detection of the main technical indicators.Work in several areas:(1)According to the design goals,based on the analysis of the principle,structure and transmission characteristics of the secondary electric cylinder,a secondary electric cylinder was designed.Its main technical parameters are a stroke of 3725mm,an axial load capacity of 20KN,and a radial load capacity of 5KN.According to the requirements of transmission power,the power,speed and torque parameters of the servo motor model were determined,and a planetary gear reducer matching the motor and the transmission screw was selected.On this basis,the relevant dimensions of the screw rods of each level are determined.(2)Based on the design of the electric cylinder drive system above,a three-dimensional model of the secondary electric cylinder is constructed,and the model is imported into the ADAMS environment,and the simulation analysis of the typical operating conditions and motion states of the electric cylinder is carried out.First verify the stroke of the electric cylinder,and then set the friction coefficient of each moving pair and rotation of the electric cylinder based on the data used in the actual calculation.The driving power of the electric cylinder servo motor is obtained through simulation.The simulation results show that the design result of the electric cylinder transmission system Consistent with the simulation results of the electric cylinder,the correctness of the design and calculation of the electric cylinder was verified.(3)Based on the finite element method,the research and analysis of the mechanical characteristics of the three key components of the electric cylinder(the base cylinder assembly,the primary piston cylinder assembly and the secondary piston cylinder assembly)are carried out.In the analysis process,the calculation of stress and deflection simplified to beam and the analysis using stress analysis software are mutually verified.The analysis results show that the load and deformation calculations of the base cylinder assembly,the primary piston cylinder assembly and the secondary piston cylinder assembly of the electric cylinder are consistent with the finite element analysis.And combined with the objective of the total mass constraint of the electric cylinder,the cylinder components with different wall thicknesses are analyzed to find the wall thickness of the cylinder that meets the overall quality requirements of the electric cylinder.(4)Aiming at the large radial load and ultra-long stroke characteristics of this electric cylinder,this article designed a super-long electric cylinder detection test bench.The test bench uses a hydraulic cylinder to connect with an electric cylinder.The hydraulic cylinder is driven by the electric cylinder.The thrust of the electric cylinder is calculated by the pressure data of the hydraulic cylinder to detect the push and pull force of the electric cylinder,and the positioning of the electric cylinder is completed on the test bench.Testing and analysis of accuracy and repeatable positioning accuracy;At the same time,the deflection test of the electric cylinder when it is separately loaded with radial load.On this basis,the axial thrust force of the electric cylinder under the maximum radial load was tested.The test results show that the main technical indicators such as the push-pull force of the electric cylinder,the deflection under the maximum radial load,and the repeated positioning accuracy meet the design goals.