径向磁化的多环嵌套永磁轴承轴向磁力解析模型

Axial magnetic force analytical model for radial magnetization multi-annular nesting permanent magnetic bearings

为了解决径向磁化双环永磁轴承轴向磁力偏小的问题,设计了径向磁化多环嵌套永磁轴承新结构。基于磁路及虚功原理法,结合径向磁化多环嵌套永磁轴承结构特点及线性叠加原理,建立了径向磁化多环嵌套永磁轴承轴向磁力解析模型。模型表明:径向磁化多环嵌套永磁轴承轴向磁力与磁环剩磁平方成正比,磁力随磁环间隙的增大而减小,随磁环数的增大而增大;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。模型计算结果与有限元计算结果基本吻合。对比计算说明:径向磁化多环嵌套永磁轴承轴向磁力远大于由原多嵌套磁环所构成的若干双环永磁轴承轴向磁力之和。

To overcome small magnetic force for radial magnetization bi-annular PMB （permanent magnetic bearings）, the new construction of radial magnetization multi-annular nesting PMB was designed. Based on magnetic circuit and the differential coefficients of magnetic field energy to virtual displacement method, connected with the structure character of multi-annular nesting PMB and linearity addition principle, the axial magnetic force analytical model of radial magnetization multi-annular nesting PMB was constructed. The model shows that the axial magnetic force of radial magnetization multi-annular nesting PMB is proportional to the second power of residual magnetism induction density, and that the magnetic force decreases with an increase in magnetic annular radial gaps and increases with an increment in the number of magnetic annulus. It also shows that the magnetic force increases with the increment of axial excursion in normal range. The calculated values of the model are basically in agreement with those of finite element method. Compared calculation shows that axial magnetic force of radial magnetization multi-annular nesting PMB is bigger than the sum of magnetic force of bi-annular PMB which be made by the magnetic annulus of multi-annular nesting PMB.