基于虚拟砂轮的钢轨打磨温度场研究

基于现场钢轨打磨作业方式,建立符合真实砂轮特征的虚拟砂轮,进而建立钢轨打磨过程砂轮-钢轨模型。运用有限元软件DEFORM仿真打磨过程中的钢轨温度场变化,分析钢轨上节点温度的变化规律,并研究不同打磨参数(包括打磨深度、进给速度、砂轮转速)对打磨温度的影响。研究结果表明:钢轨打磨过程中,钢轨经历砂轮的两次打磨作用,磨削区域温度继续升高,热影响区会进一步扩大。钢轨节点温度迅速升高过程中会经历一个小幅降低,然后继续升高达到温度最高点之后再逐渐降低。打磨参数对打磨温度有明显影响,当打磨深度从10μm增加到70μm时,钢轨最高温度从330℃升高至529℃;当进给速度从5 km/h增加至20 km/h时,钢轨最高温度从663℃降低至407℃;当砂轮转速从2000 r/min增加至3800 r/min时,钢轨最高温度从353℃升高至445℃。     

钢轨砂带打磨与砂轮打磨综合性能对比实验研究

基于自主研发的锂电驱动钢轨砂带打磨机和砂轮打磨机,以60N型钢轨廓形作为实验对象,全面对比了新型钢轨砂带打磨技术和传统砂轮打磨技术的性能。结果表明：当打磨压力在45～75 N范围内时,砂带打磨的材料去除率约为砂轮打磨的15～30倍,而当压力增大到90 N时,砂带打磨的材料去除率高达砂轮打磨的102倍;砂带打磨的振动加速度、噪声和能耗均小于砂轮打磨;砂带打磨切屑为带状,而砂轮打磨则表现为高温熔融状,同时当打磨压力增大到105 N时,砂轮打磨后钢轨表面会出现发蓝现象,而砂带打磨不会;此外,砂带打磨的横向表面粗糙度大于砂轮打磨,最高可达8μm,但满足中国铁路钢轨养护要求的最大值10μm。综上,钢轨砂带打磨技术在材料去除率、振动、噪声、能耗和温度等方面显著优于传统砂轮打磨技术,预期将成为工程实际中解决钢轨严重病害问题的有效方法之一。     

基于计算机视觉的砂轮磨损状态的在线检测

介绍了数字化曲线点磨削在线检测系统的组成和原理;采用图像拼接算法对采集到的多幅工件重叠图像进行处理;运用数学形态学边缘检测算子提取边缘得到工件的实际加工曲线,并与理论曲线作比较,从而分析出砂轮的磨损状况,获得砂轮的磨损量。实验结果表明本文所提出的方法是有效可行的。     

钢轨CBN砂轮高速打磨试验台设计与试验研究

研制一种可模拟高速打磨实际工况的高速CBN砂轮打磨试验平台、该试验台可模拟砂轮纵向、垂向进给,并且可以实现±50°偏转,实现钢轨的正向、侧向的打磨。通过试验台模拟打磨试验验证了CBN砂轮高速打磨钢轨的可行性,并得出3#复合结合剂砂轮最适合高速打磨,最优打磨砂轮线速度70m/s^80m/s,最优下压力800N^1000N。     

基于在线检测技术的砂轮磨损补偿方法研究

在硬质零件数控磨削加工中,砂轮磨损的补偿技术是常见的难点技术之一。本文研究了一种利用在线检测技术对砂轮磨损进行补偿的方法。     

高速铁路钢轨打磨技术的发展现状与展望

钢轨在服役过程中不可避免会产生波磨、裂纹、剥离、肥边等各种损伤和缺陷,严重影响其使用寿命和列车运行安全。钢轨打磨是当前国内外公认的去除表面损伤和缺陷、抑制滚动接触疲劳、改善轮轨匹配关系、延长钢轨使用寿命、提高列车运行平稳性、安全性以及乘客舒适度的有效和通用手段。概述预打磨、预防性打磨和修复性打磨三种钢轨打磨策略,然后将适用于高速铁路的钢轨打磨技术系统性的分为砂轮端面打磨技术、砂轮周面打磨技术、铣磨复合打磨技术、砂轮高速打磨技术和砂带打磨技术,并对每种打磨技术的原理、国内外相关研究及其对应的典型打磨装备发展现状进行详细评述,最后指出高速铁路钢轨打磨装备总体上呈现智能化、高效化、多样化和绿色化发展趋势,打磨技术将随着先进制造理念的不断渗透而发展进步,同时须研发我国自主化高端钢轨打磨装备,以全面提升我国高速铁路钢轨维护水平。     

钢轨打磨小车振动特性及其对打磨质量影响的研究

钢轨打磨小车是打磨列车进行打磨作业的主要执行机构,钢轨打磨小车工作时的振动状态会直接影响打磨质量。本文为探究钢轨打磨小车的振动特性及其对打磨质量的影响,分别在不同打磨速度和不同轨道波磨条件下进行了钢轨打磨小车的打磨实验,并对钢轨打磨小车在不同工况下的振动特性及打磨对钢轨不平顺质量的改善进行了现场测试。测试结果表明打磨小车在作业时的主要振动激励来源于砂轮与钢轨相互作用产生的振动,其频率与电机转子的旋转频率相同;随着打磨速度的增加,打磨小车各主要结构的振动幅值降低,且打磨后的钢轨不平顺质量有所提高;在具有波磨的轨道上进行打磨作业时,打磨小车各主要结构的振动幅值均高于在无波磨的轨道上打磨的幅值;当波磨的通过频率与打磨电机的激振频率吻合时,对钢轨打磨小车的振动和打磨后的钢轨不平顺质量均不利。     

基于Kriging插值方法的钢轨打磨温度预测

选取砂轮线速度和磨削速度为自变量、打磨温度为因变量,构建基于Kriging插值方法的钢轨打磨温度预测模型。预测结果发现:在同样的磨削速度下,当钢轨砂轮线速度增大后,其表面温度会随之上升;在同样的砂轮线速度下,如果磨削速度增大,则钢轨温度也会上升。钢轨所能达到的最高打磨温度是571.6℃,最低温度是429.8℃。该模型与测试结果的最大误差是4.5%,由此可以推断本研究构建的Kriging模型可以精确预测各打磨参数下的钢轨磨削温度。     

钢轨磨损检测装置结构设计

针对铁路钢轨磨损现状,通过对现有钢轨磨损检测装置的结构创新,设计了一种新型钢轨磨损检测装置;首先通过CCD摄像机检测模块、传感器模块对钢轨进行磨损检测,再利用图像采集模块和数据处理模块对检测数据进行分析,最后得到钢轨的磨损形式和磨损量.该装置的应用提高了钢轨磨损检测的效率和准确率,同时可对已损伤钢轨进行预警,有效延长了...     

砂轮磨损状态的声发射检测及其误差补偿方法的研究

砂轮磨损会破坏砂轮型面,对加工精度有重要影响。利用声发射方法检测砂轮的磨损状态以及修整过程,并提出了实现砂轮磨损误差在线补偿的方法。     

Research on influence of harmonic wear wheel on wheel/rail contact geometry of high-speed train

Journal of Mechanical Science and Technology - Harmonic wear is one of the common wear phenomena of high-speed train wheels. The change of wheel/rail rolling contact geometry leads to unstable...     

Feature extraction method of abrasive belt wear state for rail grinding

Abstract

Abrasive belt has the advantages of high removal efficiency and high waste collection; furthermore, it does not easily damage the rail when applied in rail grinding. However, the poor wear consistency and short service life restrict its development in this field. It is important to explore the theory and technology of monitoring the abrasive belt wear condition to evaluate the means of improving the grinding performance of the belt. This article discusses the contact stress state between the belt and the rail surface. In addition, the study establishes the belt rail grinding force model during operation using the abrasive grain distribution function. The analysis of the force model proposes that the belt abrasion condition be monitored by using the force ratio parameter of the abrasive belt in the grinding process. The extraction method of the force ratio information is proposed in accordance with the grinding environment. The results of experiments successfully verified the validity of the method.     

Automatic compensation for grinding wheel wear by pressure based in-process measurement in wet grinding

This paper deals with an application to automatic compensation of grinding wheel wear by a pressure based in-process measurement method in wet grinding. A pressure sensor is set beside a grinding wheel with a small gap. When grinding fluid is dragged into the gap by the rotation, hydrodynamic pressure, which corresponds to the gap length and the topography, can be measured. No electromagnetic properties of the workpiece and grinding wheel affect measured results. This method is applied to a CNC surface grinding machine. The pressure distribution and the relationship between the pressure and the gap length are measured. The pressure is decreased with the increase of the gap length. Its dispersion is around 1% for 0.5 μm-wear of a grinding wheel with 250 μm grit size. The dimensional error of a workpiece using the feedback of the wear is less than the feeding step, for the compensation, of 1 μm.     

Simulation and analysis of grinding wheel based on Gaussian mixture model

This article presents an application of numerical simulation technique for the generation and analysis of the grinding wheel surface topographies. The ZETA 20 imaging and metrology microscope is employed to measure the surface topographies. The Gaussian mixture model (GMM) is used to transform the measured non-Gaussian field to Gaussian fields, and the simulated topographies are generated. Some numerical examples are used to illustrate the viability of the method. It shows that the simulated grinding wheel topographies are similar with the measured and can be effective used to study the abrasive grains and grinding mechanism.     

基于砂轮电火花整形的ELID磨削实验研究

在ELID精密镜面磨削机理和氧化膜状态表征的理论指导下,通过对电火花粗整形和精整形后形成硬质层和去除硬质层的金属结合剂金刚石砂轮进行ELID电解对比实验,研究了3种砂轮ELID电解电流曲线和电解后砂轮表面氧化膜的变化,实验并分析不同砂轮电解后对GCr15轴承钢加工表面粗糙度的影响。实验结果证明:电火花整形后的砂轮,表面硬质层阻值较大,不宜直接用于ELID精密镜面磨削加工;电火花整形技术可以有效提高砂轮表面的强度和硬度,能够提高砂轮的耐磨性;为保证砂轮表面形成的硬质层最薄,电火花精整形时需选用较小的放电参数。     

Identification of grinding wheel wear using random process analysis

Profiles of grinding wheel surfaces have been analysed in terms of a random signal using virtually on-line instrumentation. By this method the contribution of the three acknowledged modes of grinding wheel wear, attritious, grit fracture, and bond-post fracture (or grit dislocation), to overall wheel wear can be readily identified.Results of tests under varying conditions of controlled force plunge cylindrical grinding are reported in detail.     

Measuring wear of the grinding wheel using machine vision

This paper proposes a new method for measuring grinding wheel contours using machine vision. The vision-aided measuring system comprises a CCD coupled with a telecentric lens, back lighting board and frame grabber. Measuring the image of the specimen with a grinded gap substitute directly captures the image of the actual grinding wheel. Using this method makes the 3 D of the topography of the grinding wheel into the 2 D of the contour of the grinding wheel. This method significantly simplifies grinding wheel wear measuring procedures compared with the traditional methods. Therefore, the presented paper provides a new method to improve efficiency and cost on measuring wear of the grinding wheel. The results show that this developed system achieves a repeatable accuracy of ±3 μm for the measurement of the grinding wheel contours.This paper has not been published elsewhere nor has it been submitted for publication elsewhere.