液体动静压电主轴关键技术综述

Review on Key Technology of Hydrodynamic and Hydrostatic High-frequency Motor Spindles

液体动静压主轴以其高回转精度、高动态刚度、高阻尼减振性和长寿命等性能优势,在高速精密机床领域获得广泛应用,但进一步适应超高速超精密加工需要,发展成为将机床主轴与高速电动机功能从结构上融为一体的液体动静压电主轴,还需解决高速化和结构集成化带来的轴承温升控制和电机性能优化等技术难题,需进一步从机理层面研究轴承特性和电动机高频电磁损耗等科学问题。因此有必要对现有研究成果进行系统分析和深入总结。回顾液体动静压机床主轴轴承技术的发展历史;从轴承油腔结构、节流器、轴颈偏斜、轴瓦弹性变形、轴承副表面形貌、液体惯性效应、热效应、润滑介质可压缩性及非牛顿特性、水润滑动静压轴承等方面,对影响液体动静压电主轴轴承特性的关键技术进行逐一分析和评述;从高速电主轴对电动机几何特性、转速—力矩特性、热特性、振动及噪声特性的要求等角度,全面评述电动机性能的电磁参数设计方法、电磁损耗机理及计算方法和电磁损伤故障防治技术;具体分析动静压电主轴整机特性优化中的关键技术难题;对液体动静压电主轴技术的未来发展趋势进行预测和展望。

High-speed spindles supported by hydrodynamic and hydrostatic hybrid bearings are widely applied in the field of high-speed precision machine tools due to highrotation accuracy, high dynamic stiffness, high vibration damping and long life. But some technical problems caused by integrated structure and high speed, including temperature rise control and motor performance optimization, are yet to be resolved when the integration of hybrid bearings and motor are developed to meet the requirements of ultra-high speed and ultra-precision machining. Also major scientific problems involved in the dynamic and thermal characteristics of hybrid journal bearings and the mechanism of electromagnetic losses of high-frequency motor are to be further studied. Therefore, it is necessary to review current achievements systematically and intensively. The retrospect of the development history of high-speed hybrid spindle is presented. The effects of critical factors and key technology on the characteristics of bearings for high-speed liquid suspension motorized spindles are analyzed and commented successively from the aspects ofoil recess structure, restrictor, journal inclination, bush elastic deformation, bearing surface topography, fluid inertia, thermal effects, fluid compressibility and non-Newtonian behavior, and water-lubricated hybrid bearings. The method of electromagnetic parameter design, the mechanism of electromagnetic loss and its calculating methods, and the fault mechanism of electromagnetic failure and its preventing methods are thoroughly elaborated to fulfill the requirements of the motor in motorized hybrid spindle from the aspects of geometric characteristics, speed-torque characteristics, thermal effects, vibration and noise characteristics. Key technical problems of optimal design of motorized spindles are analyzed in detail. And the future development tendency of motorized hybrid spindle technology is predicted and prospected.