Research on the torque characteristic of disc micromotor on axial magnetic field

In order to increase the electromagnetic torque density of micromotor with axial magnetic field, numerical analysis of permanent magnetic field and electromagnetic torque were deduced and the key factors of increasing torque density of micromotor was obtained. The numerical analysis of three-dimensional magnetic field in air gap produced by spliced sector permanent magnetic poles is done, and the way of improving flux density and permanent magnet use efficiency are given through investigating the influence of magnet thickness, height of air gap and pole interval rate and other parameters to air gap flux density and leakage flux. Based on the test of axial magnetic field and torque characteristic of micromotor, the analysis of micromotor magnetic field and calculation of torque are verified, meanwhile using the plane stator with 0.7mm thickness assemble micromotor having minimum air gap height of 1mm and its torque constant up to 3.8mNm/A.