大外径多环嵌套永磁轴承轴向磁力模型

Axial magnetic force model for large outer diameter multi-annular-nesting permanent magnetic bearings

为了提高永磁轴承承载力,设计了大外径多环嵌套永磁轴承结构。基于与实验吻合的径向磁化双环永磁轴承轴向磁力数学模型,结合大外径多环嵌套永磁轴承结构特点及线性叠加原理,建立了径向磁化大外径多环嵌套永磁轴承轴向磁力解析模型。分析表明:该型永磁轴承轴向磁力与磁环剩磁的平方成正比;磁力随磁环间隙的增大而减小,随磁环数、磁路总磁导的增大而增大;在正常轴向工作范围内,轴向磁力随轴承轴向偏移的增大而增大。该型永磁轴承充分利用了磁环两个极面,产生磁力的磁环间隙数增加,故轴向磁力明显增大。实验及有限元计算验证了该解析模型的正确性。

To enhance permanent magnetic bearings （PMB） magnetic force, the new construction for large outer diameter multi-annular-nesting PMB was designed. Based on the axial magnetic force mathematic model of radial magnetization bi-annular PMB which coincide with experiment results, connected with the structure character of large outer diameter multi-annular-nesting PMB and linearity addition principle, the axial magnetic force analytical model of radial magnetization large outer diameter multi-annular-nesting PMB was constructed. The model showed that the axial magnetic force of this type PMB was proportional to the second power of residual magnetism induction density, and that the magnetic force decreased with an increase in magnetic annular radial gaps and increased with an increment in the number of magnetic annulus and the total magnetic conductivity of magnetic circuit. It also showed that the magnetic force increased with the increment of axial excursion in normal range. The magnetic pole face of this type PMB was fully used, the number of gaps in magnetic annulus which brought magnetic force was increased, so the axial magnetic force increased markedly. The test and finite element calculated values verify the accuracy of the model.