Design And Research Of Electric Bicycle Hub Motor

Compared with internal combustion engine fuel vehicles,electric bicycles have advantages such as convenience,affordable price and ease of traffic pressure.China’s electric bicycles started in the 1990 s,and after more than 30 years of development,the sales volume now accounts for 90% of the global scale.However,in terms of the development of electric bicycle in our country,following more foreign technology and insufficient research and development,in order to realize higher power density and more safety and portability of electric bicycle motors,the electric bicycle hub motor is studied.The main contents of the study are as follows:(1)Through the study of the drive scheme of electric bicycle hub motor,it is found that the left and right half shaft drive mode is widely used in the inner rotor hub motor.Due to the instability and large noise of the left and right half shaft,a new structure of in-wheel motor with through shaft internal rotor and reduction device is proposed.In order to ensure the performance requirements of the motor design,according to the dynamic design calculation of the electric bicycle on the road,determine the design index of the new wheel motor.(2)According to the motor design index,the magnetic circuit method is adopted to design the hub motor body and determine the main size of the motor.By analyzing the matching schemes of different number of poles and slots,as well as the advantages and disadvantages of winding schemes,the scheme of 18 slots and 16 poles and double layer concentrated winding is finally determined.Then the structure of permanent magnet is designed and the permanent magnet material is determined.Determine the selection of stator groove and its internal dimensions.The RMxprt module in ANSYS Electronics Desktop software is used to calculate the performance of the motor designed above,and the motor parameters are adjusted constantly to get the required performance results.The three-dimensional modeling and total assembly of the hub motor are completed by Creo software.(3)Through Maxwell2 D motor finite element simulation software in ANSYS,the plane simulation analysis of the motor was carried out,and the distribution of magnetic field lines and the cloud diagram of static magnetic field intensity of the motor were obtained by simulation calculation of no-load static magnetic field.In addition,the stable operation performance of the motor under no-load and load was analyzed,and the no-load back electromotive force and rated parameters of the motor under load were obtained by simulation,such as rated torque and rated speed.The calculated rated power met the design power of the motor and met the requirements.The motor loss was calculated and the efficiency of the motor was analyzed to reach 90.9%.(4)Based on the optimization design theory,taking the total volume of the reducer as the objective function for optimization,the volume of the reducer decreases by 8.6%after optimization,and the overall power density of the motor is improved.ANSYS Workbench software was used to carry out finite element static and dynamic simulation analysis of the finite element model of the reducer.Statics analysis checked the strength and stiffness of the structure,which met the use requirements and verified the rationality of the structure.The dynamic simulation analysis obtained the comparison of the input and output speed of the reduction device changing with time under rated working conditions,and the meshing stress change nephogram of the gear transmission,passed the strength check,and the transmission design is reasonable.