Effect of Magnetic Alignment and Magnetic Field Molding on Magnetic Properties of C-Shape Anisotropic Sr-Hexaferrites Permanent Magnets

The alignment of the magnetocrystalline structure in a <tex-math notation="LaTeX">C </tex-math> -shape anisotropic permanent magnet is vital in determining the motor's cogging torque and induced electromotive force. In this study, a magnetic circuit simulation was conducted to test five distinct <tex-math notation="LaTeX">C </tex-math> -shape magnets, each with differing magnetic alignments. The angle between the magnetic field alignment and the vertical axis ranged from 4° to 46°. After assembling the <tex-math notation="LaTeX">C </tex-math> -shape magnets numbered 1–5 into the motor, we simulated the air-gap magnetic flux. It was observed that the air-gap magnetic flux density gradually increased as the included angle increased. In addition, the simulated motor's cogging torque and induced electromotive force also increased gradually. To verify the simulation results, the molding die design and demonstration of the magnetocrystalline <tex-math notation="LaTeX">C </tex-math> -shape magnets with alignments 1, 2, and 5 were carried out and compared with the simulation results. The findings indicate that the <tex-math notation="LaTeX">C </tex-math> -shape magnet, which has a greater included angle between the alignment magnetic field angle and the vertical direction, exhibits increased rotational torque and induced electromotive force, which is in good agreement with the simulation results. Through the application of magnetic circuit simulation software, the process of traditional magnet development can be optimized. By simulating magnetic field lines, it is possible to correct molding die and process parameters, ensuring that magnet performance in motor applications can be predicted with accuracy. In terms of the examination of the actual magnetic characteristics of <tex-math notation="LaTeX">C </tex-math> -shape magnets, the magnet's design can be verified by measuring the cogging torque and induced electromotive force after assembly into the motor. The magnetic alignment's results, confirmed by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis, can significantly reduce the product development duration for magnets used in automotive or home appliance motors.