基于方形亥姆霍兹线圈的磁场发生装置设计

Design of magnetic field generation device based on square Helmholtz coil

为了解决现有磁塑性加工中磁感应强度偏小且磁场分布不均的问题,本文设计了一种磁感应强度大且分布均匀的磁塑性加工用磁场发生装置。首先依据方形亥姆霍兹线圈理论和软磁材料的性能,确定亥姆霍兹线圈结构参数及铁芯和磁轭材料;其次利用ANSYS有限元软件对磁场发生装置进行模拟仿真研究,得出磁轭厚度、工作气隙和磁极端面形状对磁感应强度大小和磁场分布均匀性的影响,通过对模拟结果的分析,确定磁轭厚度为17 mm、衔铁磁头为锥形,且倾角为45°,工作气隙为20 mm。最后,依据理论分析结果,制作了以工业纯铁为铁芯、以纯铜丝作为线圈绕线的三级方形亥姆霍兹线圈的磁场发生装置。当电流为10 A时,通过理论计算得出电磁铁线圈温升369℃,利用特斯拉计测得其中心磁感应强度大于1 T。实验结果证实了本文磁场发生装置设计思路的可行性,为金属磁塑性加工技术的工程应用奠定了设备基础。

In order to solve the problem of low magnetic induction intensity and uneven magnetic field distribution in the current magnetic plastic machining, a magnetic field generating device with large magnetic induction intensity and uniform distribution is designed in this paper. Firstly, according to the theory of square Helmholtz coil and the properties of soft magnetic materials, the structure parameters of Helmholtz coil and the core and yoke materials were determined.Secondly, ANSYS finite element software was used to simulate the magnetic field generating device, and the influence of yoke thickness, working air gap and magnetic pole end face shape on the magnetic induction intensity and the uniformity of magnetic field distribution was obtained. Through the analysis of the simulation results, the yoke thickness was determined to be 17 mm, the armature head was conical, and the dip angle was 45°, and the working air gap was 20 mm.Finally, according to the results of theoretical analysis, a three-stage square Helmholtz coil magnetic field generating device with industrial pure iron as the core and pure copper wire as the coil winding is fabricated.When the current is 10 A, the temperature of the electromagnet coil rises 369 ℃ through theoretical calculation, and its central magnetic induction intensity is greater than 1 T measured by the Tesla meter.The experimental results confirm the feasibility of the design idea of magnetic field generator in this paper, which lays a foundation for the engineering application of metal magnetic plastic machining technology.