| As the core component of CNC machine tools,the accuracy of the electric spindle directly affects the quality of the processed products.The airflow carrying capacity of the electric spindle during high-speed operation and the unbalanced magnetic pull generated by the built-in motor can affect the eccentricity of the electric spindle rotor,thereby affecting the stability of the electric spindle.In order to analyze the dynamic behavior of electric spindle under gas-magnetic coupling and improve the stability of electric spindle operation,this article takes electric spindle as the research object and conducts the following research:（1）Based on rotor dynamics,fluid dynamics,and magnetic pull mechanics,the unbalanced magnetic pull force is calculated as a sine cosine function of the unbalanced magnetic pull force amplitude（f1）as a load constraint and introduced into the fluid solid coupling analysis.A research and analysis method for electric spindle in the gas magnetic coupling state is proposed.（2）Based on the finite element analysis software,a beam element model of the electric spindle with different motor placement positions is established,and the static analysis of the electric spindle at the middle position of the motor placement and the one end position of the motor placement is performed using the gas-magnetic coupling analysis method.The diffusion law and deformation magnitude of the two types of motorized spindle structures were analyzed through modal analysis;Through harmonic response analysis,the deformation trend and the location and magnitude of the maximum stress of two types of motorized spindle structures under the influence of external excitation are analyzed.The phenomenon of resonance,large deformation,and stress concentration in the actual working environment is avoided,which is not conducive to the subsequent research on the dynamic characteristics of the electro spindle supported by aerostatic bearings.（3）Taking the aerostatic bearing electric spindle as the research object,a modeling software was used to establish the electric spindle and gas model,and the grid was divided.And the Transient and Fluent modules in the finite element analysis software ANSYS were used for gas-magnetic coupling simulation research,and the axis trajectory of the gas hydrostatic bearing electric spindle was obtained under different rotational speeds,inlet pressures of different gas models,and rotor eccentricity（f1value）conditions.The analysis results show that increasing the rotational speed of the electric spindle will affect the enlargement of the spindle vibration range,increasing the eccentricity of the rotor（f1value）will affect the enlargement of the spindle axis trajectory range,and reducing the inlet pressure of the gas model will affect the enlargement of the spindle axis trajectory range.The results show that within a certain range,the change in inlet pressure of the gas model has a greater impact on the spindle axis displacement than the change in rotational speed;The change of different rotor eccentricity（f1value）has a greater impact on the spindle shaft displacement than the change of rotational speed,and there is a certain promoting effect between the two;When the spindle rotation accuracy error is within 0.05μm,the rotor eccentricity increases by 0.6μm（f1increasing by 20）on the spindle rotation accuracy is the same as that of increasing the inlet pressure of the gas model by 0.1 MPa.（4）To optimize the gas-magnetic coupling simulation,a method of optimizing f1（unbalanced magnetic pull amplitude）through repeated iterations is proposed,and the influence of gas inertia and displacement constraints under weak coupling on the coupling calculation is considered,making the optimized gas-magnetic coupling simulation calculation results more accurate.（5）The physical object of the electric spindle was designed and assembled,and a testing platform for the axis center trajectory of the electric spindle was built.The experimental equipment and process were described in detail.The spindle error analysis instrument was used to test the rotational accuracy of the aerostatic motorized spindle,and the gas-magnetic coupling analysis results and experimental test results at different rotational speeds were compared and analyzed. |
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