Magnetic fluid seal is one of the most mature applications of magnetic fluid. When the shaft has a large radial
runout, the classical pole piece is easily damaged. Due to its small size, the commonly used pole piece structure
harbors problems like poor seal performance under a large gap and poor processability. By exploring the distribution
law of the magnetic field on the magnet’s surface, we provided theoretical support for the magnetic
fluid seal using axially-magnetized ring magnets. New structures for the magnetic fluid seal using axially-magnetized
slotted ring magnets and the magnetic fluid seal using radially-magnetized ring magnets were proposed.
Then, comparisons were made between the classical magnetic fluid seal and the magnetic fluid seal using
ring magnets. The results revealed that the magnetic fluid seal using axially-magnetized slotted ring magnets
and the magnetic fluid seal using radially-magnetized ring magnets exhibited a certain seal capacity, which
could replace the classical magnetic fluid seal structure.