轴向磁化的双环永磁轴承轴向磁力研究

基于分析一对永磁环间隙的磁能及磁导，根据具有线性退磁曲线的稀土永磁材料特性和磁通连续原理，通过虚功原理法，得到轴向磁化的双环永磁轴承轴向磁力解析数学模型。模型表明：轴向磁化的双环永磁轴承轴向磁力与磁环剩磁感应强度的平方成正比，近似与磁环的平均半径及磁环径向宽度成正比；轴向磁力随磁环轴向长度的增大而增大，随磁环轴向间隙、径向偏心及磁环相对磁导率的增大而减小。经验证，模型计算值和实验值基本吻合。该模型显式表达了轴向磁力与各参量间的关系，使得永磁轴承设计和优化简便易行，解决了轴向磁化的双环永磁轴承轴向磁力数值计算复杂的问题。

Research on the Axial Magnetic Force of Axially Magnetized Bi-annular-shaped Permanent Magnetic Bearings

Based on the analysis of the gap magnetic field energy and gap magnetic conductance of bi-annular-shaped permanent magnetic bearings (PMB), according to rare earth permanent material property which have a linear demagnetization curve and the principle of magnetic-flux equivalency in flux paths, the differential coefficients of magnetic field energy to virtual displacement method was employed to construct an axial magnetic force analytical mathematic model of axially magnetized bi-annular-shaped PMB. This model indicates that the axial magnetic force of axially magnetized bi-annular-shaped PMB is proportional to the second power of residual magnetism induction density and is approximately proportional to magnetic annular average radius and radial width; The axial magnetic force increases with the increment of magnetic annular axial length and decreases with the increment of axial gap, radial off-centre or magnetic annular relative permeability. The calculated values of the model are basically in agreement with those measured. The relationships between the axial magnetic force and the other parameters are expressed by explicit equations in the model. The design and optimization of PMB is simplified and the calculation of axial magnetic force for axially magnetized bi-annular-shaped PMB is simplified.