Research was conducted on an axial gap-type rotating machine with the aim of increasing the torque density. To expand the torque-generating surface, an interior permanent magnet (IPM) rotor was used in a double stator-type motor that enables effective use of both sides of the rotor. This IPM rotor combines main magnets with a magnetization direction in the axial direction, auxiliary magnets with a magnetization direction in the circumferential direction, and laminated electrical steel, and fixes these components in place using adhesive. The developed motor was confirmed to have a torque density per unit volume approximately 50% higher than that of a radial-type motor. In addition, to address the manufacturing issues for a rotor structure based on this bonded structure, the yoke was manufactured using the rolling laminate method, and a new structure was developed that inserts the magnets into the yoke, integrates them with the magnetic circuit, and then fixes them in place by interference fitting inner and outer rings that are nonmagnetic reinforcing components. This structure was confirmed to have sufficient strength and stiffness, and the motor efficiency was also approximately the same as that of a rotor manufactured using the adhesive method. The new structure was ultimately confirmed to achieve a volumetric torque density 1.34 times that of a radial-type motor.
Article of Honda R&D Technical Review Vol.23 No.2 (60 - 65)