双筒永磁向心轴承磁力工程化解析算法研究

Research on Magnetism Engineering Analytical Calculation Method for Bi-barrel-shaped Radial Permanent Magnetic Bearings

针对径向磁化的双筒永磁轴承存在磁力计算复杂、由等效磁荷法得出的磁力数学模型不便推广到多筒永磁轴承及缺乏具有明确参量关系的工程化解析磁力计算公式等问题,该文用标量磁位的拉普拉氏方程经复变函数的保角变换等方法,得出一个简明的工程化磁力解析计算公式。该式能明确反映出磁力与相关参量的关系,也便于推广到多筒永磁轴承磁力计算。该式表明:径向磁化的双筒永磁轴承径向磁力分别与磁筒轴向有效长度、剩磁感应强度和永磁圆筒平均半径处磁通密度成正比,磁力随内外磁筒间隙的增大而减小,随间隙半径和径向偏心的增大而增大。实验证明,该模型计算值与实测值基本接近。这为设计径向磁化的双筒永磁轴承和具有更大承载力的多筒永磁轴承提供了一个实用的工具。

With an aim at the complexity of magnetic calculation in radial magnetization bi-barrel-shaped permanent magnetic bearings, the magnetism math model derived from equivalent magnetic charge method can not be extended to apply in solving the problems of the multi-barrel-shaped permanent magnetic bearings and the engineering analytical magnetic calculation formula in lack of definite parameter relations. This paper adopts the conformal transformation method by the LAPLACE scalar magnetic potential Equation and the complex variable function to derive a simple engineering magnetic analytical calculation formula. This formula can definitely reflects the relationship between magnetism and related parameters and also be easily extended in the calculation of multi-barrel-shaped permanent magnetic bearings. This formula indicates that the radial magnetic force of the bi-barrel-shaped permanent magnetic bearings of radial magnetization is in positive proportion with the available length of axial magnetic barrel, residual induction density and the magnetic flux density of the permanent barrel average radius and that the magnetic force decreases with an increase in the internal and external gaps and increases with an increment in the gap radius and radial off-centre. Tests prove that the calculated values by the model are found to be basically in agreement with those actually-measured, whereby providing a practical tool for designing the radial magnetic bi-barrel-shaped permanent magnetic bearings and multi-barrel-shaped permanent magnetic bearings with great loading capacity.