A new DC brushless motor, which has an equivalent driving performance to a 50 cm3 displacement scooter engine, has been developed to be equipped in a new electric motorcycle for business applications. The requirement for the maximum motor torque was mitigated by applying reduction gears and the drive unite that can be mounted on the wheel side was realized by reducing the size of the motor, together with the united structure of PDU (Power Drive Unit). In this motor, IPM (Interior Permanent Magnet) structure was implemented to cope with the high rotation speed of the motor, and the concentratedly wound stator coil was implemented for downsizing. The motor performances with the maximum power of 2.8 kW, the maximum torque of 11 Nm, the practical efficiency of 75% or more, and the maximum motor speed of 9000 r/min or more, were achieved, satisfying the specifications required for the drive train unit of business application motorcycles. In production processes, the split core stator structure and the bus rings for coil wiring were adopted to make it possible to manufacture them in the existing mass production facilities for the electric carts production, taking the cost reduction into good account as well.
Article of Honda R&D Technical Review Vol.24 No.1 (29 - 36)