Characteristic Analysis And Optimization Design Of Magnetic Screw

Linear motion is common in production and life.With the economic development and technological progress,people’s demand for linear motion has been increasing,gradually pursuing high precision,high thrust density,etc.There are two main traditional methods of realizing linear motion: mechanical conversion mechanism and linear motor.Both methods have evolved over the years,and while they are widely used,there are some problems.As a new type of linear motion mechanism,magnetic screw can achieve high thrust density and high reliability at the same time by using non-contact magnetic coupling drive.It also has the advantages of easy maintenance,overload protection,cleaning,etc.The application prospects in new energy power generation,industrial precision manufacturing,medical and other fields are very considerable.In this paper,a magnetic screw is used as the object of the study to optimize the design of thrust peak.Magnetic screws are divided into general permanent magnet,Halbach type,reluctance type and induction type magnetic screws.The structure of Halbach type magnetic screw is similar to that of ordinary permanent magnet,with high air gap magnetic induction strength and high thrust density;reluctance type magnetic screw has high permanent magnet utilization and low usage;induction type magnetic screw has dynamic adjustment capability.This paper introduces the structure and working principle of the magnetic screw,analyzes its motion and energy transfer,and derives its energy transfer formula and transmission ratio expression.The kinematic and structural characteristics of the four types of magnetic screws are presented separately;then a two-dimensional finite element analysis model of the ordinary permanent magnet type magnetic screw is established to analyze the influence of size parameters on the thrust;the simulation results show that the permanent magnet size,pole spacing and air gap size have a large influence on the peak thrust,while in the case of unsaturation,the iron core thickness of the moving rotor has almost no influence on the thrust.Based on the analysis of the influencing factors,the design of permanent magnet type magnetic screw is optimized to improve its performance while the total screw length remains constant.Based on this,the finite element simulation model is also analyzed for the other three magnetic screws,and the differences and similarities between the thrust displacement curves of the same size and those of ordinary permanent magnetic magnetic screws are also compared.Based on the analysis of the strengths and weaknesses of each of the four structures,the structure selection of the final experimental prototype is determined.Based on the analysis of the magnetic screw characteristics and influencing factors,a prototype permanent magnetic magnetic screw was designed and built.The experimental test platform of the prototype was built using rotary motor,tension sensor,crankshaft connecting rod,oscilloscope,etc.First,the basic kinematic characteristics of the magnetic screw were tested,and the rotation-linematic conversion was achieved normally.Then,the thrust displacement characteristics were tested and verified against the simulation results.Finally,an analysis of the differences and dissimilarities between the experimental and test results was carried out.