Abstract:

To overcome some drawbacks of the radial magnetic force in lack of analytical calculation model for APAM(axial placement and axial magnetization) bi-annular shaped PMB(permanent magnetic bearings),based on analysis on the gap magnetic conductance of bi-annular-shaped PMB,connected with rare earth permanent material property and the principle of magnetic-flux equivalency,the differential coefficients of magnetic field energy to virtual displacement method was employed to construct a radial magnetic force analytical mathematic model of APAM bi-annular-shaped PMB. This model indicates that the radial magnetic force of APAM bi-annular-shaped PMB is proportion to the second power of residual magnetism induction density and is approximately proportional to magnetic annular coverage diameter,and that the radial magnetic force increases with an increment in the magnetic annular radial width and axial length as well as total magnetic conductance in flux paths,and that the radial magnetic force decreases with an increment in the magnetic annular relative permeability and axial gap.The model calculated values are basically in agreement with those actually-measured.

Key words: axial magnetization;PMB;Gap magnetic conductance;radial magnetic force;mathematic model

摘要：

为了解决轴向放置轴向磁化的双环永磁轴承缺乏径向磁力解析数学模型等问题，在分析双磁环气隙磁导的基础上，结合稀土永磁材料特性和磁通连续原理，用虚位移法得出轴向放置轴向磁化的双环永磁轴承径向磁力解析数学模型。模型表明：该型永磁轴承径向磁力与磁环剩磁感应强度的平方成正比；径向磁力近似与磁环的平均直径成正比；磁环径向磁力随磁环径向宽度、轴向长度及磁路总磁导的增大而增大，随磁环相对磁导率及轴向间隙的增大而减小。模型计算值和试验值基本吻合。

关键词: 轴向磁化；永磁轴承；间隙磁导；径向磁力；数学模型