Investigation into the finite element modeling and dynamic characteristics of the assembly of spindle and motor rotor

The electro-spindle is a core component of a high-speed machine tool, and motor-rotor mounted on shaft is an important factor which influences the dynamic characteristics of the electro-spindle. When the dynamic characteristics of the electro-spindle are analyzed, the finite element method is an important computation method. However, owing that fitting the spindle shaft with the motor-rotor is considerably complicated, there are often errors between the computational result of the finite element method and the result of modal testing. Such errors result from the differences between the finite element model and the actual system. In the present paper based on rotor dynamics proposes a finite element modeling method for the motor-rotor shaft, and then adjusts the finite element model by means of modal testing and optimization methods. The research results indicate that this modeling method is accurate and efficient. Besides, in the present paper, motor-rotors of different inner diameters are mounted onto shafts of the same size, and then modal testing and a finite element analysis are applied to obtain the dynamic characteristics of the motor-rotor shaft under different assembly tolerances. The research results can be used as a reference for the tolerance design of the motor-rotor shaft assembly.