D51W-250和D51-350型辗环机辗压芯辊的通用优化设计

当前锻造业已经入了高成本时代,由于原材料上涨幅度较大,使锻造企业利润越来越小,有效的成本控制是增强企业竞争力的一个重要方向。阐述了D51W-250辗环机辗压芯辊和D51-350型辗环机辗压芯辊、滚子体、主轴的结构,分析在D51-350型辗环机使用D51W-250辗环机辗压芯辊存在的问题,通过优化D51-350型辗环机滚子体和主轴的结构设计,实现辗压芯辊的通用,降低模具使用成本。     

ANSYS在数控机床模态分析中的应用

建立了主轴的三维有限元模型，并利用大型有限元分析软件ANSYS，对主轴部件进行了模态分析，得出了主轴前五阶固有频率和振型，了解主轴部件的各阶振动模态的特点，对于研究主轴部件的动态特性是十分必要的，有利于机床主轴系统的整体设计及其制造。     

12CrMoL钢环锻件形变过烧的研究

42CrMo系列钢具有良好的综合力学性能，在风力发电设备中的重要零部件上得到广泛应用，如回转支承、齿圈类环形件、风力发电机主轴等。作为其一部分的无缝环形锻件通常采用径轴向辗环机轧制而成，使得锻件内部组织性能均匀，从而达到客户的使用要求。本文涉及的42CrMoL无缝环锻件经径轴向辗环机轧制完成，粗车加工后，     

应用有限元分析系统计算车床主轴的动态特性

机床动态特性是影响机床性能的重要因素,是在机床设计时必须要考虑的问题,模态分析主要用于确定结构或机器部件的振动特性。建立主轴的三维有限元模型,利用大型有限元分析软件AN SY S,对主轴部件进行了模态分析,得出了主轴前五阶固有频率和振型。了解主轴部件的各阶振动模态的特点,对于我们研究主轴部件的动态特性是十分必要的,有利于机床主轴系统的整体设计及其制造。     

增广传递矩阵算法在机床主轴系统静动态特性分析中的应用

以ＣＹ６１４０型普通车床主轴系统为研究对象，在集中参数模型的基础上，采用增广传递矩阵法，编制了机床主轴部件静动态特性计算的计算机程序，并应用该程序对机床主轴系统进行了静动态特性的分析计算。     

微小型机床主轴部件的特性分析

主轴作为机床的关键性部件其动静态特性对加工质量起着不可忽视的作用因此,本文针对机床的主轴部件进行了空气动力学分析,得到空气主轴的承载力和刚度,并将刀具考虑进来,研究了主轴的静力学特性和动态特性。     

环件冷辗扩中单辊随动导向运动规律研究

根据立式单导向辊随动导向冷辗环机的实际工况，建立了矩形截面环件和深沟球截面环件冷辗扩的运动学模型，分析两种环件的直径变化规律，研究了一定辗扩工艺条件下导向辊的运动规律。建立根据冷辗扩工艺来确定导向辊运动的一整套设计方法，并用MATLAB编写求解程序以求解所有的设计参数。精确地控制导向辊的运动规律有利于提高环件冷辗扩的精度。研究结果为冷辗环机的设计制造提供了依据。     

ANSYS在数控机床模态分析中的应用

建立了主轴的三维有限元模型,并利用大型有限元分析软件ANSYS,对主轴部件进行了模态分析,得出了主轴前五阶固有频率和振型,了解主轴部件的各阶振动模态的特点,对于研究主轴部件的动态特性是十分必要的,有利于机床主轴系统的整体设计及其制造。     

数控机床主轴部件动态优化设计

在对某型数控车床进行空运转、切削及模态试验的基础上，确定了机床主轴部件动刚度薄弱是引起机床切削的结构颤振方面的原因。据此，建立了机床主轴部件的有限元动力学模型，并对主轴部件进行了静、动特性的计算和动态优化设计。     

PCR-120辗环机机架的三维有限元分析

PCR-120辗环机是应用冷辗压技术制造轴承套圈的主要设备，机架则是其关键部件之一，介绍了PCR-120辗环机机架的力学模型，应用三维有限元方法对其进行分析，并根据计算结果得到了一些规律性结论。对设计过程起到了指导作用。     

A novel 5-DOFs dynamic model of aerostatic spindle considering the effect of process damping in ultra-precision machining

The existing aerostatic spindle dynamic model only analyses the effects of mass imbalance and external load, ignoring the influence of cutting system on the spindle dynamic characteristics under cutting conditions. In this paper, a 5-DOFs aerostatic spindle dynamic model is established considering the influence of the micro-scale non-linear dynamic performance of the aerostatic spindle and cutting process damping. First, an analytical identification model of process damping with blunt circular cutter is established. Then, the micro-scale dynamic characteristics of the aerostatic spindle are analyzed and a 5-DOFs aerostatic spindle dynamic model is established considering the influence of process damping. Finally, the model is simulated and the influence of process damping on the dynamic characteristics of aerostatic spindle is analyzed. The simulation results show that the process damping of the cutting system has a significant influence on the dynamic characteristics of the aerostatic spindle. This study can provide theoretical guidance for coupling research of cutting system and spindle system.

     

主轴系统的刚柔耦合接触动力学仿真分析

以高速数控铣床主轴多体系统为例,研究了主轴刚柔耦合多体系统的输出响应的动态特性。从柔性多体动力学的基本原理出发,系统地分析了主轴系统刚柔耦合的动力学模型的原理,提出基于修正的Craig-Bampton法建立主轴系统刚柔耦合的接触动力学模型的方法。基于虚拟样机模型,综合考虑齿轮传动的时变啮合刚度、间隙、摩擦和切削力等影响动态响应的接触因素,分析出轴承结合部、驱动转速和齿轮啮合等的时变特性对主轴系统动态响应的影响。仿真结果与理论和实验分析结果相一致。该仿真算法可以有效地解决考虑多动态参数激励的主轴系统的动态响应问题。     

Dynamic design for motorized spindles based on an integrated model

With increasing popularity in high-speed machining for its high efficiency, motorized spindles have been widely utilized in modern production facilities. Due to the combination of tools and built-in motors, the dynamic characteristics of motorized spindles are more complex compared with conventional spindles, and it is becoming necessary for engineers to thoroughly realize the influences of the system parameters to the system dynamics with considering the multi-physics coupling property. This paper presents an integrated model to study the electro-thermo-mechanical dynamic behaviors of motorized spindles. The integrated model consists of four coupled submodels as follows: bearing, built-in motor, thermal, and shaft model. Based on the proposed model, a design flow chart is developed and six design parameters are identified. The integrated model is validated experimentally and a design sensitivity analysis of the six parameters is then conducted based on a 170MD15Y20 type spindle. The results show that the integrated model is capable of accurately predicting the dynamic characteristics of motorized spindles, and the sensitivities of the six design parameters to the nature frequencies of the spindle system are obtained with and without the influence of the multi-physics coupling property. The coupling relationship among the electrical, thermal, and mechanical behaviors of the spindle system becomes clear from the results.     

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.     

面向机电耦合振动抑制的电主轴系统匹配特性研究

电主轴系统存在复杂的机电耦合作用,若系统机电参数匹配不当,将引起机电耦合振动,导致系统稳定性下降,工件加工表面质量降低。利用将电动机与主轴系统机械特性分离的动力学分析方法难以对系统的机电耦合振动进行有效的分析评价,也难以实现系统机电特性的优化匹配。提出基于机电耦合动力学模型的电主轴系统匹配特性分析方法,利用所提出的方法研究磨削电主轴系统逆变器工作参数、电主轴电动机电磁设计参数和砂轮机械参数对脉动转矩及定子电流频谱特性的影响,并在凸轮轴磨床上进行试验。揭示系统机电耦合振动的物理机制,提出通过优化逆变器工作参数、电主轴电动机电磁设计参数和砂轮参数抑制机电耦合振动的方法。经理论与试验分析证实,通过优化逆变器工作参数可有效抑制机电耦合振动,提高系统匹配特性和磨削质量,从而证实所提出的基于机电耦合动力学模型的电主轴系统匹配特性分析方法是有效可行的。     

基于内置力执行器的铣削颤振的主动控制

高速加工中铣削颤振不仅降低工件的表面加工质量,严重时还会造成刀具或者其他加工部件的损坏,因此对电主轴铣削颤振进行控制具有重要的意义。为对电主轴铣削过程中的颤振进行有效控制,在双绕组无轴承感应电动机的基础上,提出一种具有内置力执行器的感应型高速电主轴结构,建立电主轴—刀具系统的有限元模型、动态铣削模型、双绕组感应型电主轴电磁力模型,在对具有内置力执行器的感应型高速电主轴电磁力进行解耦后,提出基于内置力执行器的电主轴铣削颤振的主动控制方案,通过仿真分析控制器的主要参数对电主轴铣削稳定性的影响。结果表明采用具有内置力执行器的感应型高速电主轴能够有效地提高电主轴铣削的稳定区域以及在抑制铣削颤振方面具有明显效果。     

Dynamic modeling and parameters identification of a spindle–holder taper joint

Dynamic behavior of spindle–holder taper joint is critical in the spindle system of machine tool, related to the machining process. The parameters of the holder joint are significant for the spindle–holder system. This paper developed a new approach to investigate the dynamic behavior of the taper joint in modeling and parameters identification. Firstly, dynamic model is illustrated in both radial and axial directions based on the pairs of spring and damping. And frequency response function is used to identify the unknown modal parameters of frequencies and damping ratios. Secondly, a platform is designed and manufactured to establish the testing system in order to investigate the taper joint. Furthermore, taper joint of a BT50 holder is investigated, and the pre-force at the end of holder is the main consideration during the testing. The results show that the dynamic stiffness increases with the increasing of pre-force at the end of the holder. In addition, the paper discusses the phenomenon in microstructure based on peak-hollows model and the joint parameters are proved to be workable through simulation. The joint parameters are instructive to the design and manufacturing of the spindle.     

陶瓷球轴承高精密电主轴临界转速分析

主要研究陶瓷球轴承高精密电主轴动态性能。首先简化并建立轴承—转子系统模型,然后根据电主轴高精度要求选择合适的预紧力,并计算出前后轴承的径向刚度;将所建模型导入软件,根据径向刚度值进行模态分析,结果可以看出所设计电主轴在实际运转中不会产生共振;最后分析出电机转子安装位置变化对临界转速的影响不大,并对比跨距和悬伸量两个模态参数对临界转速的影响,跨距影响最大,悬伸量次之,而安装位置影响最小。该研究为电主轴的设计提供良好的理论依据。     

高速卧式加工中心滑枕模态分析与优化

卧式加工中心滑枕是连接主轴和主轴箱的关键部件,其动态性能对整机特性有重要影响。在建立滑枕实体模型和模态分析模型的基础上,利用ANSYS有限元软件进行滑枕的模态分析,提出了基于模态分析的滑枕结构动态优化设计方法。优化设计结果表明,通过合理设定滑枕内部筋板宽度及间距和上部长圆孔的尺寸,滑枕的动态性能得到改善和提高。