滚动直线导轨副热特性分析及其试验研究

高速条件下,滚动直线导轨副温升将直接影响其运动精度,为探究滚动直线导轨副的热特性及其与运动精度之间的关系,运用能量守恒定律和热对流原理建立了滚动直线导轨副温升模型和热变形模型,使用自主研发的滚动直线导轨副综合性能试验台,对国内某厂家P3级精度重预紧滚柱直线导轨副进行热特性试验研究,得到滚动直线导轨副温升变化曲线、稳定温升值、热平衡时间以及主要热变形区域。试验结果与理论值吻合,验证了所述滚动直线导轨副热特性模型的准确性。     

滚动直线导轨副额定静载荷研究

为了解决滚动直线导轨副额定静载荷难以直接测定的现状,基于滚动直线导轨副的结构特点,结合ISO14728-2关于滚动直线导轨副额定静载荷的定义和计算方法,提出利用滚动直线导轨副加载/卸载刚性曲线来间接测定其额定静载荷的试验方案,并且实际测定了某商用滚动直线导轨副的额定静载荷,验证了该试验方案的可行性。在试验的基础上,进一步分析了滚动直线导轨副的承载变形机理,指出现有滚动直线导轨副额定静载荷计算方法的不足,提出考虑承载过程中接触角改变的修正算法,计算结果显示该算法能显著降低计算误差。     

高速滚动直线导轨副综合性能测试试验台的研发

针对高档数控机床对直线滚动导轨副综合性能的要求,通过研究滚动直线导轨副的运动精度、摩擦力、速度、加速度、温升及噪声等性能指标的动态检测方法及综合性能检测关键技术,开发了一套滚动直线导轨副综合性能测试试验台,实现了滚动直线导轨副综合性能指标的检测,为改进和开发高可靠性能的滚动直线导轨副提供了试验平台。     

一种滚动直线导轨副精度自动化检测方法

随着滚动直线导轨生产技术的不断提高及应用领域的不断扩大,同时基于滚动直线导轨副检测精度要求高、项目多的特点,如何准确、高效的对滚动直线导轨副进行精度检测已经成为行业内面临的共同难题。根据相对测量原理,利用几何模拟的方法以及自动化测量手段,与意大利Marposs公司联合开发了滚动直线导轨副自动检测仪。检测结果表明,所开发的滚动直线导轨副提高了检测质量与检测效率。     

滚动直线导轨的受力分析与载荷计算

简要地叙述了滚动直线导轨副的应用场合,阐明了直线滚动导轨副的工作原理,并以滚动体为滚珠的单个滚动直线导轨副为分析模型,分析了滚动直线导轨副的内、外载荷的分布状态,建立了求解直线滚动导轨副在外载荷作用下的弹性变形的数学模型,通过此数学模型,可根据外载荷的大小求解出各滚动体所受的载荷,并求出各滚动体的弹性变形量,继而推导出整个滑块的弹性变形量,其结论对滚动直线导轨的运动精度和寿命计算提供了理论依据.     

滚动直线导轨副的温度场分析与试验研究

为了研究滚动直线导轨副发热量对零件加工精度的影响,以某公司生产的滚动直线导轨副为研究对象,在ansysworkbench软件中分别对其进行稳态、瞬态和热—结构耦合分析,得到滚动直线导轨副的理论温度场与变形场。以自主搭建的试验平台为基础,对导轨副进行了温度场试验研究。试验结果显示最大温升及趋势与仿真结果相吻合,从而验证了滚动直线导轨副有限元模型的正确性,并为滚动直线导轨副的热特性研究提供实际依据。由试验结果可知,采用该有限元模型对滚动直线导轨副进行类似热特性方面的研究,不仅使工作量变小,而且得出的结果也将真实可靠。     

滚动直线导轨副可靠性增长试验研究?

针对滚动直线导轨可靠性试验的要求,对导轨可靠性增长试验的方法进行了研究。首先介绍了滚动直线导轨副可靠性增长试验的系统构成,然后根据可靠性增长试验的流程进行分析,确定了针对滚动直线导轨副的增长试验大纲、试验方案、增长模型、故障判据分析与纠正措施等,为提高滚动直线导轨副可靠性水平提供了数据基础与技术支持。     

基于步进加载的重载滚动直线导轨副可靠性试验方法

对国产重载滚动直线导轨副的可靠性试验方法进行研究.介绍重载滚动直线导轨副可靠性试验系统的构成,提出基于步进加载的可靠性试验方法,在此基础上研究试验数据的分析与评估方法.通过指定型号重载滚动直线导轨副的可靠性试验,验证了所提出方法的有效性.     

精密滚动直线导轨副负载的计算

对精密滚动直线导轨副六滑块工作台的滚动导轨副负载进行分析 ,运用力学知识推导出在任意力和力偶矩组成的力系作用下 ,滚动直线导轨副负载的计算公式。其结论可为导轨副的刚度计算和寿命计算提供依据     

滚动直线导轨副摩擦力动态测量试验研究

滚动直线导轨副是高速高精度数控机床的重要功能部件,其摩擦特性对机床整机的力学特性具有重要影响,因此对导轨摩擦力的大小进行检测具有重要的意义。针对摩擦力检测要求,设计了一种自动检测滚动直线导轨副摩擦力的试验装置,将测量结果与手动测量进行对比,并对某一型号的滚动直线导轨副进行重复性测试,验证了该测量方法的可靠性。针对35和45型号的滚动直线导轨副进行不同速度条件下的摩擦力测试,试验结果表明,随着速度增加,导轨副摩擦力有先减小后增大的趋势。     

滚动导轨智能组合单元结合部动态特性研究

以滚动导轨智能组合单元为研究对象,借助赫兹接触理论,分析计算滚动导轨副、滚珠丝杠副和角接触球轴承的刚度,建立了滚动导轨智能组合单元结合部的动力学理论模型.通过对滚动导轨智能组合单元结合部进行相应的简化,采用弹性单元模拟结合部特性,提出结合部特性仿真分析的有限元方法,建立该机构的有限元模型,并对其进行了模态分析和谐响应分析,得到该机构的动态特性.分析结果为滚动导轨智能组合单元的动态特性优化提供了理论依据.     

直线滚动导轨的寿命分析

对由两个滑块和一根轨道构成的直线滚动导轨在施加一定工作载荷的条件下进行载荷分布和寿命的分析.结果表明:额定载荷与寿命值密切相关,其大小与载荷分布的波动状态、行程的大小及载荷偏心率等因素有关.寿命实验结果与3个参数的韦布尔分布的拟合状况非常良好,证明了理论分析的正确性.     

基于功能进化的滚动直线导轨创新设计

根据机械产品功能进化的要求,将进化思想运用于创新设计过程,通过结构特征单元的提取与变换,对滚动直线导轨的结构进行了创新设计,实现了基于功能设计产品结构的过程.     

Evaluation of electromagnetic guides in machine tools

Guides in machine tools aim for high accuracy, stiffness and damping. However, these characteristics are mainly limited by the working principle. In this paper, the implementation of electromagnetic guides in linear machine tool axes is evaluated. A milling machine prototype, with the opportunity of using ball guides or electromagnetic guides in the z-axis, is employed. Primarily, working principle and properties of the electromagnetic guide are presented and analyzed. Operating behaviour, stiffness and damping of the two guiding principles are compared. The electromagnetic guide is finally assessed in the milling process and beneficial functions of the system are presented.     

XY-table for desktop machine tools based on a new fluidic planar drive

This paper presents the design of a XY-table for desktop machine tools that makes use of a novel fluid dynamic drive principle combined with an active aerostatic planar guide for contactless motion in two directions. The presented approach reduces the installation space and the number of required components significantly when compared with electric linear motors or drives with a ball screw that are used in conventional desktop machine tools. When designing the XY-table the requirements of a micro milling process of small workpieces were considered. The arrangement of the system is presented and the drive principle is explained. Important design parameters are obtained by the support of computational fluid dynamics. Different fluid profiles for the drive are developed and compared. The results of the numerical investigations are used for the design of the XY-table whose performance is finally shown in a micro milling setup.     

Thermal error analysis for a CNC lathe feed drive system

The development of high-speed feed drive systems has been a major issue in the machine tool industry for the past few decades. The resulting reduction in the time needed for tool changes and the rapid travel time can enhance productivity. However, a high-speed feed drive system naturally generates more heat and resultant thermal expansion, which adversely affects the accuracy of machined parts. This paper divides the feed drive system into two parts: the ball screw and the guide way. The thermal behavior model for each part is developed separately, in order to estimate the position errors of the feed drive system caused by thermal expansion. The modified lumped capacitance method (MLCM) and genius education algorithm (GEA) are used to analyse the linear positioning error of the ball screw. Thermal deformation of the guide way affects straightness and introduces angular errors, as well as affecting linear positioning. The finite element method is used to estimate the thermal behavior of the guide way. The effectiveness of the proposed models is verified through experiments using a laser interferometer.     

Analysis of circular trajectory equivalent to cone-frustum milling in five-axis machining centers using motion simulator

The present paper describes the effect of the half apex angle of the cone-frustum on the motion trajectory under simultaneous five-axis motion and the effect of the sensitive direction of the ball bar when the motion trajectory is measured along the three-dimensional circular conical path. In the present paper, simulation of the measurement by means of a ball bar instrument is mainly conducted using a motion simulator developed previously. In particular, a precise mathematical model was developed to express the pitch errors of the axes of rotation of the five-axis machining center having a tilting rotary table driven by worm gears. In the experiment and simulation, primarily the center position and half apex angle of the cone-frustum were varied. In addition, two sensitive directions of the ball bar were investigated. The motion simulator incorporating the pitch error model can express the detailed trajectories obtained by the ball bar, even if the half apex angle and center position of the cone-frustum and the sensitive direction of the ball bar were changed. Then, the influence of the frictional force of the linear axes of motion, and the backlash and pitch error of the axes of rotation on the circular trajectories were analyzed. In particular, for the case of a half apex angle of 45°, the trajectory due to the errors of the axis of rotation is strongly affected by the sensitive direction of the ball bar.     

机床线性轴与导轨局部和非局部磨损产生的根本原因分析

机床线性轴需要使用在线检测方法,提供系统运行实时反馈的相关参数信息,从而了解和预测机床的性能,所以惯性测量单元(IMU)线上状态监测具有相当高的研究价值。提出基于空间滤波器的方法,通过IMU测量的运动误差来确定直线导轨的磨损情况,从而解决导轨磨损引起的平移和角度误差的变化问题,精度可以达到1.5μm和3.0μrad。主要阐述两种运动轨迹误差的跟踪方法:第一种是确定导致运动误差的导轨位置;第二是确定每条导轨非局部损坏的根本原因。这些方法有利于智能机床的优化开发,为实现机床精密控制提供可靠的理论依据。     

Influence of bearing ball recirculation on error motions of linear axes

For positioning systems utilizing linear guides and trucks with recirculating balls, a method is presented that uses the measured total error motions and the measured phase of ball loops within trucks to determine the influence of each ball loop on the error motions. The influence of ball recirculation on the error motions is estimated a priori via a least-squares solution based on data collected from a multitude of motion tests in which varying phases were measured by sensors integrated into the trucks. This method enables real-time estimation of performance degradations and identification of their sources.     

Double nut ball screw with improved operating characteristics

The performance and availability of production machines is strongly affected by the operating characteristics of the installed ball screws. In this context, the value of preloading is an important property greatly influencing the quality of the feed motion as well as the expected service life. Dynamic applications often require ball screws with high preloading values. As a result, such systems typically suffer from high friction values with the involved wear and heat generation. This paper presents a novel design principle for ball screws, allowing for a considerable reduction of the preloading and hence an overall improvement of the operating characteristics.