| The electro-permanent magnet technology has been widely used in various industries due to its advantages of strong magnetic forces,high safety performance,energy saving and environmental protection.It is applied in BHF control technology in deep-drawing process,and the magnetic attraction force is used as the BHF,which is a new type of VBHF control technology.The technology has broad application prospects in realizing flexible,automatic and intelligent control of BHF.As the core of The electro-permanent magnet technology,magnetic circuit design has always been the research emphasis and difficulty in this field.According to the electromagnetic field theory,the structure and size of the magnetic circuit of the electro-permanent magnet chuck are designed in this paper.By analyzing the influence relationship between magnetic circuit parameters and magnetic attraction force,the magnetic circuit structure is optimized to improve the magnetic attraction force per unit area.By combining the deep drawing process,the BHF device of electro-permanent magnet was designed,and the feasibility of the new control technology of VBHF is preliminarily tested.Firstly,referring to the existing electro-permanent magnet chuck model of a company,the theoretical analysis and design of the permanent magnet magnetic circuit and the electric excitation magnetic circuit in the chuck are carried out with the magnetic force of110 newtons per square centimeter as the design requirement.Before designing the permanent magnet magnetic circuit,the magnetization curve,demagnetization curve and return line of the permanent magnet material are studied.The working state of the two permanent magnets in the electro-permanent magnet chuck during the saturation magnetization working state is analyzed.It provides the necessary premise for the design of the permanent magnet magnetic circuit of the chuck.Then,the materials of the components in the chuck are selected.On the basis of this,the preliminary design of the structure and size of the permanent magnet magnetic circuit in the chuck is completed through theoretical analysis.Finally,combined with the structure and size of the chuck,theoretical calculation of the coil of the electric excitation magnetic circuit is completed with the goal of fully magnetizing the reversible magnet.Under the premise that the maximum excitation current is 22 A,the number of turns of the coil is 170,and the radius of the wire is 0.75-1.02 mm.Furthermore,using the electromagnetic simulation software,the distribution of the magnetic induction intensity and the magnetic attraction force are studied when the chuck is fully magnetized and demagnetized.The correctness of the magnetic circuit calculation is verified.The magnetic circuit structure and size is optimized with the goal of increasing the magnetic attraction force per unit area of the chuck,by using the parameter sweep of the optimization design module of the software.Determine the best design without changing the overall size of it.After the optimized chuck,the magnetic attraction force of it reaches 131 newtons per square centimeter,which is increased by 20%.It proves that the optimized magnetic circuit size is superior to the magnetic circuit size before optimization.Finally,the deep-drawing mould is designed by combining the electro-permanent magnet technology with the deep-drawing characteristics.The drawing coefficient is 0.5.The experimental material is galvanized steel with a diameter of 100 mm.The constant BHF deep-drawing experiment and the VBHF deep-drawing experiment are respectively carried out.On the premise that the fluidity of flange area is not wrinkled,the feasibility of the electro-permanent magnet technology for VBHF and the superiority over the traditional method are verified by comparing the deep drawing height. |
