Plastic Injection Molded Rotor of Concentrated Flux-Type Ferrite Magnet Motor for Dual-Clutch Transmission

Motors for dual-clutch transmission (DCT) system are required to minimize its size because of limited space on transmission. Characteristics, low cost, and high productivity are essential to DCT motor for competitiveness of mass production. Hence, concentrated flux-type ferrite magnet motor is suggested to meet the needs of DCT motor. Because concentrated flux-type permanent magnet motor has a high torque density, it is possible for ferrite magnet motor to achieve air-gap flux as high as a rare-earth magnet motor. The most important thing for the design of concentrated flux-type motor is to reduce the flux leakage. Increase in magnetic reluctance of flux leakage path is necessary to reduce the flux leakage. Accordingly, segmented rotor core is required for the size reduction of motor. In the case of segmented rotor core type, it is necessary to have complex mechanical structure to maintain circular rotor shape and fix to shaft. Since those additional structures seriously deteriorate productivity, plastic injection molding type rotor is suggested in this paper to solve the problem.