大直径磁性液体密封新结构的优化设计

磁性液体密封应用于大轴径的工况下时，环形永磁体作为磁性液体密封的磁源结构，存在因直径过大导致充磁不均匀进而引发的密封耐压能力降低的问题。为解决这一问题，设计了一种轴上永磁体的磁性液体密封结构，该结构的环形永磁体设计在轴上，与传统的磁性液体密封相比减小了环形永磁体的直径，同时减小了结构总体的轴向尺寸，使其具有结构紧凑的特点。通过有限元仿真对环形永磁体的几何参数进行优化，同时对比了新结构在极靴上开极齿和在环形永磁体上开极齿两种方式耐压能力的区别。通过模拟分析得到所设计密封结构磁通密度在极齿上的分布以及大小，并计算出理论耐压能力，证明了所设计密封结构的合理性。

Optimized design of a new structure for a large diameter magnetic fluid seal

When a magnetic fluid seal with a large shaft diameter is employed, the ring permanent magnet—as the magnetic source structure of the magnetic fluid seal—suffers from the problem of uneven magnetization. This is due to its diameter too large, which leads to the reduction of seal pressure resistance. In order to solve this problem, a magnetic fluid-sealing device with a ring permanent magnet on the shaft has been designed. Compared with traditional magnetic fluid sealing, the diameter of the ring permanent magnet is reduced, and the overall axial size of the device is also reduced. This results in the device having a more compact structure. The geometric parameters of the ring permanent magnet have been optimized, and the difference in the pressure resistance between the new device with the pole teeth on the pole shoe and the new device with the pole teeth on the ring permanent magnet has been compared. The distribution and size of the magnetic flux density of the new sealing structure on the pole teeth have been simulated, and the theoretical pressure resistance capacity has been calculated. Analysis of the simulations proves the rationality of the new sealing structure.