In order to investigate the impact of the size effect on its performance in designing axial-magnetized permanent magnet micromotor

the finite element method was adopted to simulate the magnetic field of this kind of dual rotor motor

and the flux density wave form distributed in the airgap was obtained. The influences of the external dimensions

pole numbers and magnet thicknesses of the rotor and the airgap distances on the flux density were analyzed

the analytical results were given. With the increasing of the airgap distance

the flux density under more poles reduces more quickly than under fewer poles. With the increasing of the magnet thickness

the flux density is a rising curve

and after the magnet thickness gets to a certain point

it is almost a constant. While reducing the diameter of the rotor

the decreasing of the flux density is slower and slower with the reducing of the magnet thickness. The results of the magnetic field analysis can guide the design of the microminiaturization of the motor. Moreover

the results are analyzed theoretically and the simulated values are almost consistent with the experimental values.