Experiment And Simulation Analysis Of Relationship Between Electromagnetic Vibration And Loss For Motorized Spindle

With the need of high-precision machining technology and the development of high speed machining industry, the motorized spindle is applied in high speed Computer Numerical Control(CNC) machine tools as the core components. The quality of motorized spindle directly decides the performance of machine tool, so it is particularly important to study the performance on motorized spindle. The loss and the vibration evaluate the overall performance of motorized spindle, and the loss and the vibration is produced during high-speed operation. The loss of the motorized spindle decreases the work efficiency and causes the temperature rise and the motor burnout. The vibration and the noise of motorized spindle affect the machining precision, service life and work environment. The temperature rise of motorized spindle is mainly caused by the loss. If the heat dissipation of motorized spindle is not ideal, the heat accumulation of motorized spindle will eventually lead to the thermal deformation, and the electromagnetic vibration of motorized spindle will be directly affected after thermal deformation. This paper aims to analyze the coupling relationship between loss characteristics and vibration characteristics of motorized spindle, and also analyze the theory and method which reducing the loss and electromagnetic vibration of motorized spindle.This paper firstly describes the working principle, structure and characteristics of motorized spindle. Analyzing the electromagnetism theory, thermal theory, thermal deformation theory and vibration theory of motorized spindle is necessary. On this basis, the coupling theory about loss, temperature rise, thermal deformation and electromagnetic vibration of motorized spindle are analyzed.This paper establishes motorized spindle unit finite element model. In order to consider the influence of the high harmonic in frequency converter to the electromagnetic loss, a magnetic circuit coupling model for motorized spindle based on time-step finite element method is built. This paper calculates the core loss, the solid loss and the stranded loss of motorized spindle. At the same time, the transient loss of motorized spindle is analyzed. The results showed that the core loss is the largest and the stranded loss is the minimum under the SPWM inverter power supply.This paper calculates the electromagnetic loss of motorized spindle with the time-step finite element model and the heat transfer coefficient of motorized spindle. This article proposes a magnetic-thermal coupling analysis method for motorized spindle, then analyzes the magnetic field and the temperature field of motorized spindle under the speed of 30000 r/min. At the same time the paper analyzes the influence on improving the distribution of the temperature field for motorized spindle with the new ceramic materials, and lays the foundation which improving the thermal performance of motorized spindle.This paper goes on simulation analysis coupled multi-physics for motorized spindle based on the magnetic-thermal coupling model, then analyzes the electromagnetic field, temperature field and structure field under the steady state. The results show that the temperature of the ceramic motorized spindle is lower than that of the metal motorized spindle. And the deformation of the former is less than that of the latter under the same condition.This paper establishes the model coupled multi-physics based on multi-physics analysis, and calculates the model of motorized spindle after thermal deformation. In order to calculate the radial electromagnetic force, this paper gets the air gap flux density with the magnetic circuit coupling model for motorized spindle. This paper investigates the effect that air-gap of motorized spindle on electromagnetic vibration and loss. Through the simulation about the loss and the electromagnetic force of motorized spindle at speed of 8000r/min, 10000r/min, 12000r/min and 15000r/min, this paper gets the relationship between the loss and the electromagnetic force of motorized spindle. Finally this paper puts forward the temperature-rise experiment and the vibration experiment of motorized spindle with the dynamometer for motorized spindle under different rotating speeds. And the simulation model and the simulation theory are verified by experiments.