矿用钢丝绳损伤检测磁通回路优化设计

Optimization design of magnetic flux circuit for mine wire rope damage detection

漏磁通检测法是应用最广泛的矿用钢丝绳损伤检测方法,目前未有考虑磁通回路中磁噪声信号对钢丝绳损伤漏磁通检测信号影响的研究。基于钢丝绳损伤漏磁通检测原理,构建了漏磁通检测等效磁路模型,采用Ansoft Maxwell有限元软件对磁通回路的磁场分布进行仿真,结果表明除主磁通和钢丝绳损伤漏磁通外,磁通回路中还存在多处磁噪声回路,易对钢丝绳损伤漏磁通检测信号造成干扰,其中衔铁导磁路径的漏磁通和两侧永磁体与空气介质之间耦合漏磁通的影响最大。基于仿真分析结果,对磁通回路进行了优化设计:将衔铁与永磁铁接触部位由直角结构改为圆角结构,以减小该部位的漏磁通,增大衔铁导磁路径中的主磁通,进而增强钢丝绳损伤漏磁通检测信号;采用高导磁材料设计环形磁桥路屏蔽装置并安装在损伤漏磁通检测区域,引导两侧永磁体与空气介质之间耦合漏磁通的走向,减小耦合漏磁通对钢丝绳损伤漏磁通检测的影响。实验结果表明,磁通回路经优化后,钢丝绳损伤检测信号特征较优化前更加明显,采集信号由6.14 mV增大至18.59 mV,验证了优化方案可提高磁通回路传递效率,对损伤漏磁通有聚合增强效果,减小了永磁体与空气介质之间耦合漏磁通与钢丝绳损伤漏磁通的叠加效应,有利于提高钢丝绳损伤检测准确性。

The magnetic flux leakage(MFL) detection method is the most widely used method for detecting the mine wire rope damage, and there is no research on the influence of magnetic noise signal in magnetic flux circuit on the MFL detection signal of wire rope damage. Based on the principle of MFL detection for wire rope damage, the equivalent magnetic circuit model of MFL detection is constructed, and the magnetic field distribution of the magnetic flux circuit is simulated by Ansoft Maxwell finite element software. The results show that there are many magnetic noise circuits in the magnetic flux circuit besides the main magnetic flux and the MFL of wire rope damage, which are easy to interfere with the MFL detection signal of wire rope. The MFL of armature magnetic conduction path and the coupling MFL between permanent magnets on both sides and air medium have the greatest influence. Based on the simulation results, the magnetic flux circuit is optimized. The contact part between the armature and the permanent magnet is changed from a right-angle structure to a rounded structure to reduce the MFL at this part, increase the main magnetic flux in the armature magnetic conduction path, and then enhance the MFL detection signal of wire rope damage. The annular magnetic bridge circuit shielding device is designed with high magnetic conductivity material and installed in the damage MFL detection area so as to guide the direction of the coupling MFL between the permanent magnets on both sides and the air medium, and reduce the influence of the coupling MFL on the detection of wire rope damage MFL. The experimental results show that after the optimization of the magnetic flux circuit, the characteristics of the wire rope damage detection signal are more obvious than those before the optimization, and the collected signal increases from 6.14 mV to 18.59 mV. It is verified that the optimization scheme can improve the transmission efficiency of the magnetic flux circuit, have the aggregation and enhancement effect on the damage MFL, and reduce the superposition effect of the permanent magnet-air coupling MFL and the wire rope damage MFL, which is conducive to improving the accuracy of wire rope damage detection.