Honda has been proposing and developing a Transverse Flux Motor (T.F. motor) in order to shorten axial length of the motor for hybrid electric vehicles (HEVs). In contrast to conventional motors that are composed of a stator core (made from magnetic steel sheet) and winding wires, the T.F. motor is a new type of three-dimensional magnetic circuit motor composed of a soft magnetic composites (SMC) core and a coil. While reducing axial length and achieving a simple stator architecture comprised of just five parts, the new motor raises issues including the need to improve motor efficiency and the development of techniques for the manufacture of rectangular wave-shaped coils.
To improve motor efficiency, we conducted a parameter study of the SMC core material and manufacturing conditions to establish the optimum required specifications for reducing iron loss. In order to successfully manufacture rectangular wave-shaped coils, we developed a coil film that fulfilled the required criteria for both manufacturability and insulation, in addition to developing a new press-forming manufacturing method that bends and reduces the diameter of ring-shaped coils in order to form rectangular wave-shaped coils. We created and tested a prototype of the T.F. motor using the improved SMC core and the rectangular wave-shaped coils produced using the new press-forming method. The average motor efficiency in JC08 mode improved from 79.1% to 83.7%.
