五轴联动加工中心主轴系统的结构优化

对五轴联动加工中心主轴系统进行动力学仿真分析,对原主轴系统的轴承支承系统和主轴结构进行了动态优化设计。提出了双排轴承的设计方案。对于主轴结构,论文建立了以主轴前端动态变形最小为目标函数的优化模型,并对主轴结构进行了优化设计,从而提高了主轴系统的静力学和动力学特性,满足了设计要求。     

车床主轴系统结构设计参数对其动力特性的影响

本文以车床主轴为研究对象,应用有限元和实验建立轴和支撑系统的动力学模型。采用计算机仿真技术,研究轴承等效径向(轴向)刚度与阻尼参数、轴承预紧力、跨距,附加集中质量和阻尼等设计参数对主轴系统动力特性的影响规律, 为主轴系统的动态优化设计进行了有意的探索。     

主轴系统结构设计参数对其动力特性影响研究

文章以某车床主轴为研究对象，应用有限元和实验建立轴和支撑系统的动力学模型。采用计算机仿真技术，研究轴承等效径向（轴向）风度与阻尼参数、轴承预紧力、跨距，附加集中质量和阻尼等设计参数对主轴系统动力特性的影响规律，为主轴系统的动态优化设计进行了有意的探索。     

考虑支承跨距的非线性转子系统动力学特性研究

根据主轴变形几何模型求得主轴前端总位移关系式,依据前端最小位移确定主轴的最佳支承跨距,进而建立了考虑支承跨距的转子轴承系统非线性动力学模型.运用数值积分方法,给出最优跨距支承下转子系统的非线性动力学响应,采用轴心轨迹、相图及Poincar6图分析了转速对系统动力学响应的影响.结果表明:当转子轴承系统在最佳支承跨距下运行...     

TX6916镗铣床主轴模态分析及其动态性能试验

为检测TX6916落地镗铣床样机的动态性能,采用有限元和试验的方法对其主轴进行振动研究.利用ANSYS对主轴进行模态分析,在三维实体模型的基础上建立了轴承-主轴系统有限元模型,求解得出前5阶固有振动频率和相应的主振型.利用锤击法对主轴进行动态响应试验,通过试验测试数据和有限元计算结果对比分析,验证了有限元模型的合理性,并对误差原因进行讨论,为该型镗铣床的进一步动力学研究及其优化设计提供了重要依据.     

数控螺旋锥齿轮磨齿机主轴系统的温度场分析与仿真

以某种数控螺旋锥齿轮磨齿机为研究对象,分析其主轴系统的主要热源、传热途径及边界条件,在此基础上建立主轴系统热特性分析的有限元模型.用有限元法计算三维瞬态温度场分布,得到主轴系统达到热平衡的时间约为3h,最高温度发生在前端轴承处,最高温升为28.275℃,为以后计算主轴的热变形及优化设计散热结构奠定了基础.     

高速外圆磨床砂轮主轴系统动态特性研究

基于有限元素法,对高速外圆磨床砂轮主轴系统进行了动态特性分析。研究了不同主轴支撑刚度、轴承间距和陀螺效应对主轴组件系统动态特性的影响及其变化规律,为高速外圆磨床砂轮主轴系统结构的优化设计提供了理论依据和指导。     

重型卧式数控车床主轴系统动力学分析

通过对重型卧式数控车床主轴-滚动轴承系统的研究,建立了前支承为双列圆锥滚子轴承,后支承为单列圆锥滚子轴承的主轴系统的动力学微分方程。通过改变圆锥滚子轴承内滚道接触角、圆锥滚子的半锥角、主轴系统角频率和滚子数量,在考虑与轴承性能参数有关的变刚度和变阻尼系数的基础上,得到这些参数对主轴—轴承系统的影响。为机床主轴系统的优化设计提供理论依据。     

空气静压电主轴特性分析与实验

空气静压电主轴是数控机床的关键功能部件之一,主要围绕其动态特性进行分析研究。首先,针对空气静压电主轴结构及轴承结构进行分析。然后,基于空气静压电主轴的动力学建模,对其进行模态分析和谐响应分析。最后,针对空气静压电主轴进行动态测试实验,并对比仿真分析结果和实验测试结果。研究表明载荷的大小决定了空气静压轴承的偏心率,同时对电主轴前端的刚度起决定性作用。谐响应分析表明在主轴固有频率左右,空气静压电主轴前端的振动位移较大。     

关于轴承预紧力对轴系性能影响的仿真分析

高性能电主轴包括电机驱动与控制系统、主轴轴承系统、润滑与冷却系统、轴承预紧系统等多种重要部件,其中轴承预紧力技术是电主轴的关键技术之一.论文对不同预紧力下的主轴轴承刚度进行了理论计算,并对不同轴承预紧力下的主轴轴承系统进行了模态和谐响应分析.结果表明;随着轴承预紧力的增加,轴承刚度逐渐增大,轴系固有频率逐渐增大,主轴前端和后端径向响应位移逐渐减小,主轴中间径向响应位移则逐渐增大.     

基于ANSYS数控车床静压气体轴承主轴的模态分析

针对气体静压轴承支撑的精密数控车床主轴系统工作高精度的要求,在机床工作过程中,主轴高速旋转,静压气体轴承的支撑刚度随着转速动态变化。为了了解主轴工作过程中的动态特性,应用Pro／E软件对主轴进行三维建模,并用ANSYS对其进行模态分析,得到各阶固有频率和振型。掌握数控车床主轴各阶振动模态的特点,有利于气体轴承支持下的数控车床主轴结构设计,为机床的进一步研究及优化提供理论依据。     

Analysis of the machining stability of a milling machine considering the effect of machine frame structure and spindle bearings: experimental and finite element approaches

Chatter vibration has been a troublesome problem for a machine tool toward the high precision and high-speed machining. Essentially, the machining performance is determined by the dynamic characteristics of the machine tool structure and dynamics of cutting process of spindle tool. Prediction of the dynamic behavior at spindle tool tip is therefore of importance for assessing the machining stability of a machine tool at design stage. This study was aimed to evaluate the machining stability of a vertical milling system under the interactive influence of the spindle unit and the machine frame structure. To this end, a realistic finite element model of a vertical milling tool was generated by incorporating the spindle-bearing model into the head stock mounted on machine frame. The influences of the dynamics of spindle-bearing system and the machine frame structure were investigated respectively. Current results show that the machine tool spindle system demonstrates different dynamic behaviors at different frequency ranges, which are also characterized as structural modes and spindle modes, respectively. In particular, the maximum compliance of spindle tool tip was found to occur at the bending vibrations of spindle shaft and vary with the preload amount of spindle bearing. The machining stabilities were predicted to different extent, depending on the exciting modes which could be related to the influences of machine frame and spindle unit.     

高速电主轴动态设计方法

基于传递矩阵法与滚动轴承分析理论，研究高速电主轴的轴系动态特性分析方法，用Matlab工具研发了一套电主轴动态分析与设计通用软件。以某高速磨削用电主轴为例，完成其动态分析与结构优选设计。结果表明：所提出的电主轴动态设计方法可行，研发的高速电主轴动态设计通用软件可成功地用于产品设计。     

基于虚拟设计的铣头式机床主轴结构动态特性仿真分析

铣头式机床的主轴是多组件、复合支承的特殊结构，影响机床动态性能。在虚拟设计的数字样机上采用有限元法和模态综合技术对主轴进行了动态特性仿真分析找出薄弱环节。根据分析结果。修改和优化主轴结构设计。     

紧凑型高速电主轴拉刀机构静动态特性分析与优化

介绍了紧凑型高速电主轴的结构设计,建立了主轴-拉刀机构双转子系统模型,研究了电主轴拉刀机构的静动态特性,得到了工作状态下电主轴的静态位移、振型、固有频率以及关键点的响应位移。对主轴-拉刀材料、轴承预紧力、轴承组跨距、主轴-拉刀接触刚度以及主轴-刀柄接触刚度等参数进行优化设计。结果表明优化后电主轴的静动刚度均满足要求、固有频率提高、电主轴安全工作频率区间增大。电主轴模态测试结果证明了以上结果的可靠性。该研究为紧凑型高速电主轴的设计提供了理论基础。     

陶瓷轴承主轴单元动特性的实验研究

对陶瓷轴承主轴单元的动态性能特点进行了实验研究。研究发现,在相同预紧和脂润滑条件下,陶瓷轴承主轴单元的阻尼系数比钢轴承主轴单元小,主轴端部的直接动柔度比钢轴承主轴单元大。研究结果为采用陶瓷轴承主轴单元的高速和超高带数控机床的动态设计提供了实验依据。     

高速加工机床主轴支承系统的研究

介绍高速加工机床用电主轴的特性及应用现状,分析加工机床电主轴系统的理想结构、陶瓷球轴承、电磁浮轴承、液体动静压轴承的特性及其在高速主轴单元中的应用,并以高速数控随动曲轴磨床的主轴支承系统设计为例,说明如何选用设计合适的高速加工机床主轴支承系统。     

Dynamic Performance of the Ceramic Bearing Spindle Unit

Dynamic performance of a ceramic bearing spindle unit is studied in this paper. It is found that the damping coefficients of the ceramic bearing spindle unit are smaller than those of the steel bearing one,direct mobility in the front nose of the ceramic bearing spindle unit is larger than that of the steel bearing one after the experimental modal analysis for a standard spindle unit. The experimental results provide a scientific basis for the dynamic design of high speed and extra-high speed machine tool with the bearing spindle units.     

Dynamic characteristics of spindle with water-lubricated hydrostatic bearings for ultra-precision machine tools

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.