Development of High Power-Density Motors for Electric Axles using Nd-Based Bonded Magnets

In recent years, a demand has arisen for smaller traction motors with higher power. This study focused on high-speed rotation for miniaturization and developed a prototype motor using Nd-based bonded magnets. It had a maximum rotational speed of 34,000rpm, which is twice that of existing 50kW-class motors. The motor achieved the desired performance in the test in combination with a reducer. As a result, the weight of the prototype motor was reduced by 54%, and a power density of 6.7kW/kg was achieved.