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根据几何参数和简化原则建立电主轴实体模型。采用滚动轴承拟静力学模型准确计算轴承刚度,建立主轴-轴承系统有限元模型,设计模态测试实验较好地验证了仿真结果。基于主轴有限元模型,以主轴转子外圆直径、内孔直径、悬伸量、支承跨距以及轴承配置形式为设计变量;以主轴转子一阶固有频率最大和质量最轻为优化目标;以主轴转子前端静变形、最大应力、主轴各段尺寸均在限定范围内为约束条件,对电主轴转子进行优化设计。将提出的优化方法应用于某磨齿机电主轴,优化后主轴一阶固有频率提高33%,质量减轻21%,实现了电主轴高刚性和轻质量优化目标,为电主轴数字化设计提供技术支持。 相似文献
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电主轴的静刚度是其主要性能指标,是机床加工零件精度和质量的保证。轴承作为电主轴的核心支撑部件,其预紧力的增加或减小对主轴的刚度有着重要的影响,同时预紧力的变化也会影响轴承的使用寿命。为了确定轴承的最佳预紧力,通过仿真分析了预紧力的变化对主轴静刚度、固有频率以及使用寿命的影响。分析结果表明:随着预紧力的增加,主轴的静刚度和固有频率都有明显的提高,但同时降低了轴承的使用寿命。 相似文献
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作为数控机床的核心功能部件,高速电主轴的动力学特性直接影响着工件的加工精度。建立了高速电主轴的轴承-转子动力学模型,计算了角接触球轴承的动态支承刚度和轴承-转子系统的固有特性,并且研究了不同转速下轴承支承刚度对系统固有频率的影响。以2GDZ60型高速电主轴为研究对象,测试了系统的1阶固有频率和2阶固有频率,与理论计算值相比较误差较小。 相似文献
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《机械制造与自动化》2016,(2):50-53
以某大功率高速铣削加工中心电主轴系统为研究对象,采用有限元法,综合考虑高速状态下主轴系统阻尼比、陀螺力矩效应和轴承刚度软化3种因素,建立了高速电主轴系统的动力学方程。得到了主轴系统由转速引起的陀螺力矩效应,轴承刚度变化两种因素影响下的前6阶固有频率,并进一步得到了上述3种因素影响下的刀尖处频率响应。结果表明在高速状态下,轴承刚度的软化对固有频率的影响大于陀螺力矩效应;而主轴系统的结构阻尼比会减弱轴承刚度软化对刀尖处频率响应的影响。 相似文献
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Jenq-Shyong Chen Yii-Wen Hwang 《The International Journal of Advanced Manufacturing Technology》2006,30(1-2):10-19
Trend of the high-speed and high efficiency machining has pushed the continuous demand of higher spindle speed and power for the machining center application. Because the extremely high speed produces significant centrifugal force, it creates a need to predict the spindle dynamical characteristics at dynamic states. This work presents analysis results of the spindle dynamic of a motorized high speed spindle with angular ball contact bearings. For a machining center, two major subsystems determining the overall spindle stiffness are the shaft/bearing subsystem and the draw bar mechanism subsystem. Shaft/bearing stiffness as well as the natural frequency decreased at high speeds due to the bearing softening and gyroscopic effect. The bearing softening is the major reason of the reduced spindle stiffness, while the gyroscopic effect plays the secondary effect. Angular contact ball bearing softening at high speed is due to the reduced contact load and increased contact angle at the ball/inner-raceway contact interface caused by the centrifugal force. For the draw bar mechanism, analysis results show that the dynamic draw force at high speeds is significantly increased from that designed at the static state. Because the toolholder/spindle interface stiffness is proportional to the draw force, centrifugal force theoretically contributes a plus to the spindle stiffness at dynamic state. The dynamic draw force, however, is dependent on the friction loss inside the draw bar mechanism. Because of the low friction coefficient, the ball-type mechanism is superior to the wedge type mechanism. 相似文献
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A key component of ultra-precision machine tools is the spindle. The motivation for this study was to improve machining accuracies in precision cutting and grinding by pursuing improvements in the spindle characteristics by designing a sophisticated spindle with water-lubricated hydrostatic bearings. The static bearing stiffness of the developed spindle was investigated in previous studies. In addition to the static bearing stiffness, the dynamic characteristics regarding bearing stiffness also affect significantly on the machining results. In this study, dynamic characteristics of the developed spindle with water-lubricated hydrostatic bearings were investigated via simulations and experiments. Not only bearing dynamics but also rotor dynamics were considered in this study.In the simulation studies, the spindle dynamic characteristics were analysed based on the transfer matrix method. A spindle rotor supported with hydrostatic bearings was represented by discrete sections of the rotor. The mathematical model of transverse linear vibrations of the spindle rotor was derived with distributed parameters for these discretized rotor sections. As a result of the analysis on the amplitude-frequency characteristic, radial displacements of the rotor due to bearing displacement and bending deformation were defined. Then, the frequency characteristics were represented with Nyquist plots. Resonant frequencies and amplitudes formation in the transverse vibration of the rotor were determined. The influence of rotor bending deformations on spindle compliance was assessed. Furthermore, the study examined the influences of the supply pressure of the lubricating fluid, radial clearance and journal diameter of the hydrostatic bearings on the amplitude of the rotor vibration, and the resonance frequency of the system.Furthermore, the dynamic characteristics of the spindle were examined experimentally. The simulation results were in good agreement with the actual spindle dynamics obtained experimentally. The influence of the structural parameters of the rotor and the operating parameters of the bearings on the spindle dynamic characteristics was also determined. It was verified that the amplitude of the vibration of the rotor overhang part was dominantly affected not by bearing stiffness but by bending stiffness of the bearing journal of the front bearing and the length of the rotor overhang.Then it was verified that the resultant displacement of the rotor in the radial direction due to the influence of the bearing characteristics and the structural effect of the rotor is significantly small. Practical recommendations to improve the spindle design in terms of the dynamic characteristics of the spindle with water-lubricated hydrostatic bearings were also derived. 相似文献
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商学来 《机电产品开发与创新》2014,(1):105-106,101
以某型车削中心主轴为研究对象,采用弹簧阻尼单元模拟动静压轴承支承的方法,建立主轴三堆有限元模型,.同时进行静力学分析,模态分析,分别得到静刚度、固有频率和振型。分析了主轴的应变与应力情况,比较了主轴在共振和设计工况下的振型,为该主轴结构改进设计提供依据. 相似文献
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液体静压主轴油膜滑移现象的分析及试验研究 总被引:1,自引:0,他引:1
针对液体静压主轴运动过程中动态特性问题,研究微尺度下油膜滑移对轴承承载力,刚度及动态刚度的影响。把微尺度下发生的速度滑移引入到油膜性能方程中,结合液体静压主轴系统平衡方程推导出了主轴系统承载力、刚度及动态刚度表达式,研究了油膜初期主轴静动态性能及油膜动刚度特性。从仿真结果中得到油膜滑移的发生使得承载力及刚度增大,最大刚度对应油膜厚度减小。最后刚度检测试验间接得出了实际主轴系统油膜流动过程中,存在油膜微滑移现象。本项研究为液体静压主轴微尺度下油膜滑移现象及性能的研究探索了一条新途径。 相似文献
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大功率空气静压轴承电主轴 总被引:4,自引:1,他引:3
介绍自行研究设计的空气静压轴承高频电主轴设计上的特点:一是空气轴承采用“全支承”结构,显著地提高轴承的承载能力和刚度;二是较国内同类型产品其变频电机的输出功率显著增大,可适应高效磨削的要求。 相似文献