水润滑轴承电主轴转子动力学特性分析

发布时间：2018-04-04 02:19

本文选题：电主轴　切入点：水润滑轴承　出处：《东南大学》2016年博士论文

【摘要】：随着高速加工技术的发展,电主轴正向着高转速、高刚度、大承载、高可靠性和长寿命等方向发展。近年来,水润滑轴承电主轴技术倍受国内外关注,相比于传统的滚动轴承电主轴、油润滑轴承电主轴以及空气轴承电主轴等,水润滑轴承电主轴技术具有高回转精度、低摩擦、低功耗、高阻尼、大承载以及长寿命等优良的综合性能。水润滑电主轴设计,首先要开展主轴转子-轴承系统动力学特性分析,特别是电主轴在实际加工过程中,受切削力的影响,主轴不仅作沿坐标轴x,y,z方向的平动,还作绕x轴、y轴的转动,因此有必要探讨倾斜效应对水润滑轴承及电主轴动态特性的影响。1)考虑倾斜效应的水润滑轴承静动特性建模分析。基于流体润滑理论,考虑水的紊流效应以及主轴的倾斜效应,建立了水润滑径向轴承和水润滑止推轴承流体润滑数学模型,推导了水润滑径向轴承和止推轴承的平动、倾斜以及平动-倾斜耦合动态特性系数的计算方法；通过与实验数据进行比较,表明所建立的模型和算法可用于分析水润滑轴承的静动特性。分析结果表明：倾斜效应对轴承的平动、倾斜以及平动-倾斜耦合动态特性系数的变化影响显著。2)含大止推轴承的水润滑电主轴刚性转子动力学特性分析。基于牛顿第二定律和动量矩定理,建立了五自由度刚性转子动力学模型；考虑了水润滑径向轴承和水润滑止推轴承的平动、倾斜以及平动-倾斜耦合动态特性系数,分析计算了主轴的动力学特性；并将计算结果与不考虑止推轴承倾斜效应的动力学模型计算结果进行比较。研究结果表明：不考虑止推轴承倾斜影响得到的主轴轴端径向稳态响应位移、径向不平衡响应幅值均大于考虑止推轴承倾斜影响得到的主轴轴端径向位移、径向不平衡响应幅值。止推轴承倾斜效应对带大止推盘水润滑电主轴的转子-轴承动力学影响不可忽略。3)高速水润滑电主轴挠性转子动力学特性分析。建立了高速水润滑电主轴挠性转子动力学模型,考虑径向轴承的倾斜效应,推导了含轴承倾斜效应的单元传递矩阵,完成电主轴的临界转速、不平衡响应分析。分析比较了采用传统的不考虑倾斜效应的8系数传递矩阵模型与本文建立的考虑轴承倾斜效应的32系数传递矩阵模型计算得到的主轴动态特性,结果表明：两种模型对电主轴的一阶临界转速的影响可以忽略,传统模型得到主轴不平衡响应峰值大于考虑轴承倾斜效应模型的不平衡响应峰值。通过将理论计算结果与实验数据进行比较,验证了本文所推导的32系数模型的正确性。将考虑轴承倾斜效应的32系数轴承模型应用于主轴动力学计算,能更准确地模拟电主轴的转子-轴承动力学性能。
[Abstract]:With the development of high-speed machining technology, motorized spindle is developing towards high speed, high stiffness, large load, high reliability and long life.In recent years, water lubricated bearing motorized spindle technology has attracted much attention at home and abroad. Compared with traditional motor spindle of rolling bearing, oil lubricated bearing motor spindle and air bearing electric spindle, water lubricated bearing motorized spindle technology has high rotary precision and low friction.Low power consumption, high damping, large load and long life.In the design of water lubricated motorized spindle, the dynamic characteristics of the rotor bearing system should be analyzed first. Especially, the motorized spindle is affected by the cutting force in the actual machining process, and the spindle not only moves in the direction of the coordinate axis xyyz.It is necessary to study the influence of tilt effect on dynamic characteristics of water lubricated bearing and motorized spindle. 1) Modeling and analysis of static and dynamic characteristics of water lubricated bearing considering tilting effect.Based on the theory of fluid lubrication, the mathematical models of water lubricated radial bearing and water lubricated thrust bearing are established, considering the turbulent effect of water and the inclination effect of spindle, and the horizontal motion of water lubricated radial bearing and thrust bearing is deduced.By comparing with experimental data, it is shown that the proposed model and algorithm can be used to analyze the static and dynamic characteristics of water-lubricated bearings.The results show that the tilting effect has a significant effect on the dynamic characteristics of the hydro-lubricated motorized spindle rotor with large thrust bearing.Based on Newton's second law and the theorem of moment of momentum, the dynamic model of a rigid rotor with five degrees of freedom is established, and the coupled dynamic coefficients of water lubricated radial bearing and water lubricated thrust bearing are considered.The dynamic characteristics of the spindle are analyzed and calculated, and the calculated results are compared with those of the dynamic model without considering the tilting effect of thrust bearings.The results show that the radial steady-state response displacement of the shaft end is larger than that of the thrust bearing tilting effect, and the radial unbalance response amplitude is larger than that of the thrust bearing tilting effect, and the radial displacement of the shaft end is larger than that of the thrust bearing tilting effect.Amplitude of radial unbalanced response.The effect of thrust bearing tilting effect on rotor bearing dynamics with large thrust disc hydrolubricated motorized spindle can not be ignored. 3) dynamic characteristics of flexible rotor of high speed water lubricated motorized spindle are analyzed.The dynamic model of flexible rotor of high speed water lubricated motorized spindle is established. Considering the tilting effect of radial bearing, the element transfer matrix with bearing tilting effect is derived, and the critical speed and unbalanced response analysis of the motorized spindle are completed.The dynamic characteristics of spindle calculated by using the traditional 8 coefficient transfer matrix model without considering the tilting effect and the 32 coefficient transfer matrix model with bearing tilting effect established in this paper are analyzed and compared.The results show that the influence of the two models on the first order critical speed of the motorized spindle can be neglected. The traditional model shows that the peak value of the unbalance response of the spindle is greater than that of the model with bearing tilting effect.The correctness of the 32 coefficient model derived in this paper is verified by comparing the theoretical results with the experimental data.The 32 coefficient bearing model considering the bearing tilting effect is applied to the dynamic calculation of the spindle, which can more accurately simulate the rotor-bearing dynamic performance of the motorized spindle.
【学位授予单位】：东南大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TG502.3

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