Analysis Of Vibration Characteristics Of Rotor Bearing System Under Electromechanical Coupling

This paper takes the drive motor of a company’s vehicle electric drive system as the research object.First,it analyzes the radial electromagnetic force and the unbalanced magnetic tension and the eccentricity of the rotor-bearing system of the motor under different eccentric conditions.Secondly,by analyzing the structure of the driving motor rotor,a 3D model of the rotor was established and modal simulation analysis and experimental tests were carried out on it.Finally,an electromechanical coupling multi-body dynamic model of the motor system was established on this basis.The motion state of the motor rotor under two different eccentric conditions is analyzed,and the displacement and vibration of the rotor center and the force of the rotor support bearing are simulated and solved.The main work can be divided into the following points:(1)According to the nonlinear relationship between the eccentricity of the motor rotor and the unbalanced magnetic tension of the motor,this paper uses the energy method to theoretically analyze the unbalanced magnetic tension and electromagnetic torque when the rotor-bearing system is eccentric.The electromagnetic simulation model of the drive motor was established with Motor CAD,and the radial electromagnetic force experienced by the rotor under different eccentric states was simulated and analyzed.(2)Taking the drive motor rotor of a company’s electric drive assembly as the research object,a three-dimensional model of the rotor system was established with Autodesk Inventor.And use ABAQUS to carry on the modal simulation analysis to it,get its first six natural frequencies.At the same time,a modal experiment test was carried out on the motor rotor,and the correctness of the modal analysis was verified by comparing the results of experiment and simulation.(3)The electromechanical coupling multi-body dynamics model of the drive assembly motor was established with COMSOL.Based on the model,the vibration characteristics of the rotor-bearing system during static eccentricity and dynamic eccentricity of the rotor were analyzed,and the center motion trajectory diagram of the rotor was drawn.The vibration displacement and vibration acceleration of the rotor center are obtained,and the force of the supporting bearings at both ends of the rotor under the two eccentric states,as well as the displacement of the bearing and the motion track of the bearing center are analyzed.The analysis results show that the static rotor eccentricity will change to mixed eccentricity when the motor is running at high speed;when the rotor is dynamic eccentric,the amplitude of the unbalanced magnetic tension caused by the mass deviation during the low-speed operation of the motor is small,and the vibration of the rotor is mainly caused by the mass eccentricity.As a result,when the motor speed reaches a certain height,the unbalanced magnetic pulling force will rise rapidly,and the rotor amplitude will increase significantly,and under the combined action of the mass eccentricity and the unbalanced magnetic pulling force,the vibration amplitude at the corresponding frequency of the rotor maximum speed will be much larger than Amplitude corresponding to other frequencies.