新型混合径向磁轴承结构及其磁力特性

针对当前永磁偏置径向磁轴承的永磁磁路的磁通密度低,磁力小,缺乏自稳定的问题,提出一种应用于立式轴流泵的新型混合径向磁轴承结构.应用分子电流法及虚位移定理建立新型混合径向磁轴承承载力的非线性模型及其线性化方程,分析得出新型径向混合磁悬浮轴承在径向某个自由度上具有自稳定的特点,且永磁轴承可以减小系统总的位移负刚度.研究结果表明,采用Halbach阵列结构后,混合磁轴承气隙的磁通密得到很大提高.电流刚度和位移刚度与平衡点的初始电流及初始间隙密切相关,在平衡位置附近电流刚度和位移刚度呈线性变化,当气隙增大时仍保持较好的线性度,而当气隙减小时呈现一定的非线性特性.

Structure and magnetic characteristics of novel hybrid radial magnetic bearing

Aimed at some problems in the permanent magnetic circuit of available magnetic radial bearings with permanent magnet bias such as small magnetic force,low magnetic flux density,and lack of self-stabilization.A new hybrid radial magnetic bearing structure for vertical axial flow pump was proposed.The nonlinear model and linearization equation of the bearing capacity of the new hybrid radial magnetic bearing were established by using current molecular method and virtual displacement theorem.It was found by analysis that with this permanent magnetic suspension bearing,its self-stabilization would exhibit in some radial degrees of freedom and the total displacement negative stiffness of the system could be reduced.The investigation result showed that the air gap flux density was greatly improved with the new hybrid magnetic bearing when Halbach array structure was used.Current stiffness and displacement rigidity were closely related to initial current and initial gap at the equilibrium position.Around the equilibrium position,the variation of current stiffness and displacement rigidity was linear.With the increase of air gap,its linearity was well kept.With the decrease of air gap,however,a certain nonlinear characteristics exhibited.