针对现有在线动平衡方法存在的缺陷,提出了一种新的基于磁流体流变效应的在线动平衡方法。从理论上分析和阐明了局部磁场作用下磁流体由于内部压力变化导致产生质量偏心的原理;利用线激光投影测量法对不同磁场条件下的磁流体表面进行实验测试,对所得磁流体三维形貌图分析可知,在局部磁场作用方向上磁流体质量偏心程度随磁感应强度的增加而增加,验证了利用磁流体流变效应动平衡的可行性;为实现对任意大小方向失衡量校正,设计了平衡容器及3个互成120°的共轭C型电磁铁,通过构建电磁铁有限元模型,对给定电流下电磁铁周围磁感应强度进行分析;实验中利用电磁铁线圈电流变化实现在线动平衡。动平衡实验结果表明,磁流体流变效应产生的质量偏心可用于转子失衡校正,一次校正后不平衡量下降率达65.14%,实验也验证了本文提出的动平衡方法的效果。
Focusing on the defects of the existing online dynamic balancing methods, a new online dynamic balancing method with magneto-rheological effect of magnetic fluid is proposed. The principle of eccentric mass generation due to the change of internal pressure of magnetic fluid under local magnetic field is theoretically analyzed and expounded. The surface topographical images of magnetic fluid are obtained with line laser projection measurement method. It is found that the degree of eccentric mass increases with magnetic induction in the direction of the local magnetic field, thus the practicability of dynamic balancing with magneto-rheological effect is verified. The structure of balancing container and three conjugated C-type electromagnets with 120~ each other are designed to implement the correction of unbalance with any arbitrary magnitude and angle. Constructing a finite element model of the designed electromagnet, the magnetic induction intensity of electromagnet is analyzed under given current condition. In the experiment, on-line dynamic balancing is accomplished by utilizing current change of the electromagnet coil. The result of balancing experiment shows that eccentric mass generation due to magneto-rheological effect of magnetic and the unbalance is decreased by 65.14% fluid can be employed to correct the rotor unbalance, after once correction. The performance of the proposed method is also verified.