Analysis Of Dynamic Characteristics Of Electric Spindle-bearing-tool System Of High-speed Milling Machine

High-speed electric spindle as the core component of CNC machine tool processing,its performance is a key factor restricting the machining efficiency and accuracy of the machine tool.With the development of high-speed electric main shafts in the direction of high speed,high precision and high efficiency,higher requirements have been placed on the dynamic characteristics of electric spindles.Due to the complex structure and high speed of the electric spindlebearing-tool system,it is easy to cause excessive vibration,cracks,thermal deformation and other failures,which seriously affect the machining accuracy and quality of the processed parts.Therefore,the study of the dynamic characteristics of high-speed electric spindles is very important Meaning.First of all,based on the finite element method,the dynamic model of the spindle bearing tool system of high-speed milling machine is established,the condition of bearing stiffness is calculated and analyzed,the dynamic characteristics of the spindle bearing tool system are studied,and the two different situations with and without the tool are compared and analyzed.It is found that after the tool is installed,the natural frequency and critical speed of the system are reduced,and the system is stable Poor.Secondly,the unbalance response characteristics of the high-speed milling machine electric spindle-bearing-tool system are analyzed,and the influence of the size and position of the unbalance on the dynamic characteristics of the system is obtained.With the increase of the unbalance,the system vibration increases and the bearing preload is increased.Force can effectively improve the vibration of the system.In addition,through theoretical analysis,the dynamic model of milling system is established,and the dynamic characteristics of the electric spindle bearing tool system under the action of milling force are analyzed.It is found that different milling force parameters have different effects on the dynamic characteristics of the system,and the feed per tooth has the greatest impact,followed by the milling depth.The dynamic characteristics of the system are affected by the bearing preload.Under the action of milling force,the system can increase the bearing preload,improve the ability of resisting deformation and improve the reliability of the system.Finally,in the uneven temperature field,the thermal deformation of the system occurs.Different bending moments are applied to the nodes to simulate the thermal deformation fault in the uneven temperature field,and the dynamic characteristics of the system are analyzed.It is found that with the increase of bending deformation,the dynamic response of the middle part of the rotor is the largest,and the system is sensitive to the low-order frequency response.The thermal deformation of the electric spindle system can be improved by increasing the bearing preload.Based on the above research,the dynamic characteristics of the spindle under unbalanced force,milling force and thermal deformation are analyzed to provide a theoretical basis for the development of the electric spindle-bearingtool in the direction of high precision,high speed,high power,large torque and high reliability.