Magnetic force analytic model of step conical PMB

The cost of precision conical permanent magnetic bearings (PMB) is very expensive in the engineering manufacture. Step conical PMB, which consists of by piling up several couples PM rings of different diameters with rectangular cross section, in a conic disposition, characterized by such advantages as low cost and easy manufacture. Based on the magnetic field of planar point magnetic charge, virtual work principle, and superposition theorem, combining two parallel rectangular section permanent magnets (PM) and the structure trait of step conical PMB, the magnetic force analytical model of step conical PMB is established, and the relationship between magnetic force and structure parameters of step conical PMB is analyzed, and the correctness of the magnetic force analytical model is validity by ANSYS simulation, comparisons show that the analytical solution closely matches with the results of the finite element analysis. The results indicate that the magnetic force of step conical PMB is proportional to the magnetic annular average perimeter and the square of residual magnetism induction density, and that the magnetic force increases with an increment in the magnetic annular section size, the axial magnetic force increases with an increment in the axial deflection, the radial magnetic force increases with an increment in the radial deflection. The paper provides technical support for design and structure parameters optimization of step conical PMB.