气体悬浮电主轴动态特性研究进展

Review on the Dynamic Characteristics of Aerostatic Motorized Spindles

在高效超精密加工中,气体悬浮电主轴存在电动机高速拖动能力衰减过快、电磁偏心激振、高次谐波激振和电动机定、转子发热严重以及主轴高速带来的温度效应和气流惯性效应等一系列技术难题。因此有必要对气体悬浮电主轴动态特性的影响因素进行系统分析和深入总结。分析气体悬浮电主轴的技术现状以及存在的问题;从轴承结构、气体流动形态、电磁偏心激振和不平衡响应等四个方面对电主轴稳定性的影响进行评述;综述轴承类型、轴承参数、表面粗糙度和轴颈倾斜对系统刚度的影响;阐述系统临界转速和电动机转速—力矩特性以及主轴高速带来的温度变化和气流惯性对主轴系统的影响;围绕主轴的回转精度,对主要因素、回转误差形成机理和精度测试与误差分离技术逐一评述;最后对气体悬浮电主轴技术的发展趋势进行预测和展望。

There are a series of technical problems in the application of the aerostatic motorized spindle to meet the requirements of ultra-high speed and ultra-precision machining,such as electromagnetic losses of high frequency motor,eccentric electromagnetic excitation,high harmonic excitation,thermal effects and inertial effects caused by motor high speed running.Therefore,it is necessary to make systematic analysis and intensive review on the factors which influence the dynamic characteristics of aerostatic motorized spindle.The retrospection of the development history and status of the aerostatic motorized spindle is presented.The effects of critical factors on the stability of high speed motorized spindles are analyzed and commented from the aspects of aerostatic bearing structure,gas flow forms,eccentric electromagnetic excitation and unbalance response,then the influences of bearing type,bearing parameters optimization,surface roughness and journal inclination on the system stiffness are summarized.The effects of critical speed,speed-torque characteristics on the high speed performance and its byproducts of thermal effects and gas inertia are analyzed in detail.The principle factors that influence the rotation accuracy,the mechanism of rotation erro informaticion,the accuracy text and error separating technique are commented.Finally the development tendency of the aerostatic motorized spindle technology is predicted.