Develop of High Performance Direct-driven In-wheel Motor for Electric Vehicle

Direct-driven in-wheel motor is widely concerned because of its advantages as a solution to distributed power vehicles. However, in-wheel motor has high performance requirements and complex multi-field coupling effects which cause the high difficulty on design and manufacturing. There are few high performance in-wheel motors in China. To overcome these challenges, the method of joint design of mechanic, electric, thermal and magnetic multi-physics is proposed to be applied to the design of direct drive hub motor. Through applying the technology of segmented stator core, over-molding technology of the hybrid bobbing, precision winding technology, high thermal conductivity potting technology, integral potting process, lightweight structural design, high line speed oil seal technology, etc., a high performance in-wheel motor was developed. The motor achieved high torque density of 21.3 N•m/kg and high power density of 2.2 kW/kg which can be compared with international advanced level, the result proved the effectiveness of the method and related techniques. © 2019 Journal of Mechanical Engineering.