Application of Sinter Diffusion Bonding to Motor Rotor Core of Hybrid Car

摘要

This paper focused on sinter diffusion bonding technology applied to rotor core in hybrid car, which requires both magnetic properties and mechanical properties at a time, and analyzed diffusion bonding of sintered materials and the bonding area as a factor affecting it. It was obtained that the strength of the bonding zone depended on the bonding area, The satisfactory bonding strength was accomplished by increasing the bonding area through the pressure by press fitting of the inner and outer components in addition to the difference in thermal expansion of the sintered material. The obtained results showed that the density of the outer part should be close to 7.0 +- 0.05 g/cm~3 and the press fitting clearance should be in 0.275 approx 0.335 mm, considering the soft magnetic properties and diffusion bonding strength. The rotor which bonding area ratio was more than 50 percent made it possible to achieve both sufficient durability and functionality.