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介绍一种自动测量铁路车辆轮对参数的新装置。采用工业控制计算机、结构光视觉传感器、步进驱动以及数字滤波、图像自动识别、曲线拟合等多种数据处理技术,实现了轮对外形尺寸、轮对踏面擦伤和剥离等参数的全自动非接触测量。 相似文献
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铁路机车轮对综合参数自动检测系统 总被引:6,自引:0,他引:6
针对铁路机车轮对检修的要求,研制了机车轮对综合参数自动检测系统,该系统能完成对轮缘磨耗、踏面磨耗、踏面擦伤等重要参数的自动测量,从而提高了机车轮对检测的自动化程度及轮对检修作业的效率. 相似文献
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阐述了一种基于振动加速度原理的在线式踏面擦伤检测装置的工作原理及实施方案。通过对其所采集到的信号进行有效的分析,去除干扰,可使擦伤信号易于判定。 相似文献
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机车轮对JM、JM2、JM3磨耗型踏面及其剥离 总被引:1,自引:1,他引:0
机车轮对踏面剥离的产生因素很多,如轮箍材质、高速重载、制动过热、踏面型式,等等。对20世纪80年代以来南宁铁路局已应用过的机车轮对JM、JM2、JM3磨耗型踏面的剥离问题,作了比较和探讨。 相似文献
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对以轮对踏面滚动圆作为轮缘测量基准和以轮缘顶点作为轮缘测量基准两种情形下运用机车的轮缘厚度进行了分析比较,指出以轮对踏面滚动圆作为轮缘测量基准是更加科学、经济、合理的测量方法,有利于延长米轨机车轮缘的旋轮周期和降低运营成本。还对米轨东方红21型机车轮缘测量基准提出了修改建议。 相似文献
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根据轮轨几何的理论分析 ,ST2 型踏面轮对与 6 0kg/m轨相匹配 ,它的等效斜度λe 在横向位移yw=1~ 7mm时是 0 1,而yw>7mm时λe=0 3。这一特性表明 ,ST2 型踏面车轮不但具有好的曲线减磨效果 ,并且能以较高速度在直线上平稳运行 ,适合于提速机车的运行要求。上海机务段自 1999年 3月开始至今 ,已在沪宁、沪蚌线运行的 4 7台DF11型机车上先后装用ST2 型磨耗形踏面车轮 ,用以牵引快速列车 ,机车振动情况正常。为了实际测定DF11型机车装用ST2 型踏面车轮的振动性能 ,经用英国生产的MKⅡA型测振仪在司机室中央地板处测得它的横向振动平衡性指标W2 ,在 90~ 14 0km/h范围内 ,处于优良及合格水平。理论和实践均证明 ,ST2 型踏面车轮 ,用于14 0km/h的提速机车上是合适的 (由于运转时分限制 ,测试的最大速度为 14 0km/h)。值得指出的是 ,采用ST2 型踏面车轮牵引快速列车 ,有减缓车轮踏面剥离及轮缘磨耗的好处 ,而踏面剥离及轮缘过早磨耗正是提速机车落轮修的主要原因。 相似文献
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轮轨非对称接触及形面损伤问题分析 总被引:2,自引:0,他引:2
随着列车运行速度的提高,车轮形面损伤问题也日益严重。车轮形面损伤分为踏面剥离、车轮失圆和轮缘磨耗等类型。车轮形面损伤后会导致车辆的不平稳运行,使车辆一方面产生低频、中频和高频的振动,影响车辆的运行平稳性和乘坐舒适性,另一方面会引起车辆内部的噪声,车轮损伤严重时甚至会直接导致车辆脱轨事故的发生。车轮损伤问题是由轮轨接触非对称现象所引起的,轮轨非对称接触分为对称踏面与非对称钢轨的接触、非对称踏面与对称钢轨的接触以及非对称踏面与非对称钢轨的接触三种类型。当车轮形面或钢轨损伤后,就会导致轮轨非对称接触的发生,而轮轨非对称接触又会加剧车轮形面的损伤。为了提高车辆的动力学性能和运行稳定性,必须避免轮轨强非对称接触的发生。 相似文献
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指出随着列车的提速 ,机车整体车轮踏面极易产生裂纹源 ,并向内部发展 ,轻者造成踏面剥离掉块 ,重者造成崩裂。同时 ,机车车轮的制造质量问题也是产生上述故障的重要原因之一。它们都会影响机车运行的安全。介绍了机车整体车轮超声波探伤的关键要素及试验情况 相似文献
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This article presents a technical review on the effects of thermal loads evolved at the wheel–rail–brake contact interfaces. These dynamic contact interfaces develop heat transfer conditions of widely varied thermal level. Their modeling to identify the sources for a variety of defect formation, observable on wheel tread or rail surface, is very important. The railway system, in general, has to bear axle load, friction load, and thermal load arising from their contact conditions in addition to traction and dynamic loads. The defects arising from the interaction of thermal load and other loadings may be identified as hot spots, shelling, spalling, rolling contact fatigue (RCF), and corrugation. The mechanisms for the formation of such defects are pivoted over the existing thermal environment of dynamic interacting surfaces. This review summarizes the works of early investigations and recent advances in modeling the heat transfer conditions required to estimate the temperature distribution at the contact zone. The heat partitioning method for both drag and stop braking conditions, in the presence of rail chill effect, is emphasized. Thermal gradient, introduced by localized temperature rise in the contact zone, in the presence of variable friction coefficient, promotes the RCF process. These alter the residual stresses in the contact region to cause a structural shakedown, aggravate plastic flow and activates ratchetting phenomenon in rails. The evolution of thermomechanical surface and subsurface fatigue cracks are also discussed for the completeness of this article. The effect of all such defect formation, emerging from thermal loading condition, and their countermeasures for defect mitigation are presented in this review. This abridged technical documentation envisions attracting more research in the area to improve wheel–rail set design and performance standards to extend enhanced safety and comfort to rail transport operation. It is opined that the thermomechanical loading, their effects on promoting defect formation and propagation should be studied in combination instead of the current practice of treating them separately. 相似文献
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Azade Haidari 《热应力杂志》2013,36(1):34-50
Nowadays, the railway vehicles are widely used in many countries as one of the most important transportation systems. Nucleation and growth of fatigue cracks in railway wheels stem from different factors such as wheel-rail rolling contact, thermal loads between wheel-rail and wheel-brake block created in braking process, presence of structural defects in wheel material, and so forth. Also, increasing speed and axle loads of wheels aggravates these factors. These cracks can reduce wheel life and even in severe cases derailment may occur. Therefore, the thermo-mechanical fatigue problem of wheels is a very important issue as is doing an accurate mechanical and thermal analysis of the investigation and estimation of fatigue life of wheels, and also, the prediction of crack behavior under thermo-mechanical loads is necessary. In this article, stress fields created by combined thermal and mechanical loads in railway wheels is investigated. Thermal stresses are usually created as a result of frictional heating produced by applying brake shoes on the wheel tread and also as a result of the occurrence of slip between wheel and rail at the braking stage. The obtained results confirm the important effects of thermal loads on stress fields and fatigue life of wheels. In this article, thermal loads are determined by modeling the contact of the rail-wheel and two brake blocks and by identifying heat partition factors and friction coefficient between these components. One of the other advantages of the presented work is modeling of wheel rotation, while in many of the similar investigations either this rolling is not modeled or its effect is simplified as translating pressure distribution along the rail-wheel contact region. The use of a 3D FE analysis for determination of rail-wheel contact pressure instead of Hertz contact theory is also noteworthy. 相似文献
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