Research On Ultrasonic Vibration Assisted Drawing Process Of Submersible Linear Motor Core

With the development of economy,the requirements of energy conservation and emission reduction are constantly improving.How to improve the efficiency of crude oil exploitation and reduce energy loss is particularly important,as a new type of rodless lifting equipment,the submersible linear motor has solved many problems existing in the original mechanical sucker rod and improved the oil recovery efficiency,so it has a good application prospect.Due to the structural defects of the submersible linear motor core welded after punching,the magnetic resistance is increased,which leads to the serious heating problem of the motor during operation.Based on the advantages of ultrasonic assisted plastic forming,an ultrasonic vibration assisted deep drawing process was proposed for the original motor core forming process.Aiming at the ultrasonic vibration assisted forming process of linear motor core,the following work is carried out in this paper:(1)The uniaxial tension tests of 50ww470 non-oriented silicon steel sheet under different temperature,strain rate and lateral vibration excitation were carried out.It has been found that the yield strength of the material decreases in the temperature range of100-250℃,and the plasticity of the material also deteriorates compared to room temperature.Under the lateral ultrasonic vibration condition,the material yield strength and flow stress begin to decrease compared with the non-vibration condition.The finite element material model was established based on the uniaxial tension tests,which was used to simulate and analyze the subsequent forming process.(2)When the motor iron core prepared by multi-layer drawing is assembled with the pie copper winding,the forming part needs to have a small inner and bottom fillet,so it is of great significance to explore the limit bending radius of 50ww470 for drawing.In order to investigate the ultimate bending radius of 50ww470,a V-shaped bending finite element model was established by using Dynaform,and the minimum bending radius of 50ww470 silicon steel sheet was calculated.At the same time,in order to explore the springback of materials after forming under ultrasonic vibration,the V-shaped bending experiment assisted by ultrasonic vibration was carried out.The springback law of bending parts under different punch fillet radius,different amplitude and different holding time was studied.It was found that the introduction of ultrasonic vibration could reduce the springback of bending parts.(3)In order to solve the serious heating problem of linear motor in operation,the original welding forming process of motor core was improved,and a new ultrasonic vibration assisted drawing forming process was proposed.Combined with ultrasonic vibration assisted drawing process experiment and finite element simulation,the feasibility of different experimental schemes was explored.The study found that after applying ultrasonic vibration in drawing process,reduce the forming force,material deformation is uniform,wall thickness distribution more uniform,and ultrasonic vibration can inhibit forming a wall thickness thinning,at the same time the introduction of ultrasonic vibration reducing the amount of springback.By comparing different experimental schemes,it is found that the forming scheme of superposition after three-layer plate drawing is feasible.The corresponding solution strategy is put forward for the problems existing in the drawing of multi-layer plates,and a "shaping" procedure is put forward for the forming process defect of the bottom rounded corner being too large,which effectively solves the problem of the bottom rounded corner being too large.