High Magnet Utilization and Reduced Flux Leakage in Bevel Magnetic Gears Using Spoke/V-Type Hybrid Configuration

Although recent studies on transverse-flux magnetic gears (TFMGs) have reduced flux leakage, challenges such as low magnet utilization and high manufacturing complexity persist. These drawbacks not only compromise the inherent advantage of easy assembly in TFMGs but also limit torque density per magnet volume. To address these issues, this study proposes a hybrid bevel magnetic gear incorporating spoke-type and V-type permanent magnet configurations, denoted as BMG-SV. The design aims to reduce flux leakage and enhance torque density per magnet volume by combining a conical structure with the flux-concentrating characteristics of V-type magnets. The proposed design also preserves the inherent advantages of TFMGs, including ease of assembly and manufacturability. Finite element analysis (FEA) is conducted to evaluate the flux leakage and torque density per magnet volume of the proposed BMG-SV, and to compare its performance with those of a conventional TFMG and a spoke-type bevel magnetic gear (BMG-SS). The simulation results show that the proposed BMG-SV effectively reduces flux leakage, achieving approximately a 52% reduction in the maximum flux leakage density in air compared with the conventional TFMG. In addition, the torque density per magnet volume is improved by 1% and 43.7% compared with the TFMG and BMG-SS, respectively. Finally, a prototype of the BMG-SV is fabricated, and experimental measurements of surface magnetic flux density, torque, and rotational speed are performed to validate the simulation results.