高温磁悬浮轴承励磁绕组制造技术

针对国内外高温励磁绕组存在的缺陷与不足,提出了一种新型的迷宫形励磁绕组结构,首先通过电火花线切割制造出单层迷宫形线圈,并在线圈匝间和层间充分均匀地填充耐高温绝缘材料;然后通过真空钎焊工艺实现多层迷宫形线圈的牢固焊接,最后将焊接成型的多层线圈封装成迷宫形绕组,并应用于单自由度高温磁悬浮轴承试验台中,实现了550℃被悬浮物体近20h的稳定悬浮.研究结果表明:线圈焊缝的高温电阻值小,抗剪切强度满足要求,焊缝的金相组织致密均匀;绕组匝间和层间绝缘性能良好;迷宫形励磁绕组在原理和工艺上是可行的.对高温悬浮试验后的迷宫形绕组内部形貌进行观察后发现封装线圈的高温绝缘材料存在一定的缺陷,有待进一步研究. 

Excitation coil manufacturing technology for high temperature active magnetic bearing

In view of many defects and deficiencies of high temperature excitation coil at home and abroad,a new type of maze like excitation coil structure was proposed.Firstly,the monolayer maze like coil was manufactured by electric discharge machining (EDM) wire cutting,and the high temperature resistant insulating material was put into the gap of coils sufficiently and uniformly.Secondly,the vacuum soldering process was utilized to connect each layer.Finally,the packaged coils were used in a single degree-of-freedom (DOF) high temperature active magnetic bearings (HTAMB) test,and the HTAMB can achieve stable levitation for 20 hours at 550℃.The results show that the welding line resistance value is small,the shear strength of the selected solder and welding line shaped by copper parent metal are credible and coil insulation performance between turns and layers is fine in high temperature environment.Therefore,the high temperature excitation coil is feasible in theory and technology.The oxidized and impaired excitation coil internal structure caused by high temperature levitation test shows that the high temperature resistant insulating material used in encapsulated coil has certain flaws,and they need further research.