机车车轴尺寸测量不确定度评定

介绍了机车车轴几控制尺寸的测量不确定度分析.     

火车车轴尺寸测量精度控制

随着我国轨道交通领域的快速发展,对于货车、高铁、地铁等车辆各部件的检修工作量快速增加,特别是轮对的检修,直接关系到车辆的正常运行和安全,以往的人工已不能满足快速增长的工作量,为此我们针对轮对设计了各种测量设备,车轴自动测量机即为其中之一,用于车轴各尺寸的测量,而采取措施和方法保证其测量精度显得意义重大。     

40 Cr 重载车轴断裂失效分析

目的研究车轴在热校直过程中的断裂原因和机制。方法通过对该车轴进行化学分析、金相检测、力学性能检测,对车轴断裂的性质和产生原因进行了分析和讨论。结果准确得出了车轴断裂的性质和产生原因。结论车轴制造工艺不合理,导致车轴轴头产生了严重的过热组织,这是车轴断裂的主要原因;原材料中较多的非金属夹杂物等材质缺陷,造成了材料的综合力学性能降低,尤其是材料的屈服强度降低,是车轴断裂产生的重要原因。建议改进车轴的制造工艺,过热严重的车轴应报废处理。     

铁路车辆用LZ50钢车轴裂纹的形成机理

铁路车辆用车轴经锻造及机械加工后,在其表面常发现纵向裂纹,造成车轴报废。采用光学显微镜、扫描电子显微镜、能谱仪、维氏硬度计等分析手段,对LZ50钢车轴表面裂纹形成的机理进行了研究。发现车轴微裂纹的形成可有两种机理:一是车轴钢坯中的显微缩松在锻造时被轧扁但未完全弥合所致;二是由车轴钢坯中的氧化铝类夹杂物在锻造时形成裂纹源,导致车轴微观组织脆性穿晶断裂。     

高速列车空心车轴应用研究

我国铁路车辆面向高速、重载两方面发展,空心车轴在高速列车中应用广泛。从高速列车空心车轴的应用研究出发,较系统地介绍了空心车轴的特点、检修维护、超声波探伤技术。同时阐述了影响车轴疲劳寿命的材质选择、结构设计、生产工艺等因素。     

铁道车辆车轴裂纹产生原因分析及技术对策

对生产实践中车轴出现的裂纹进行分析,从轴坯质量和锻造工艺两方面研究提高车轴质量的迷径,确保以最低的成本,生产高质量的车轴,以提高车辆使用寿命,确保行车安全.     

LZ50钢车轴发纹成因分析

采用光学显微镜、扫描电镜以及能谱仪等仪器分析手段对LZ50钢车轴机加工后出现发纹的原因进行了分析。结果表明:该车轴发纹是由于钢中的氧化铝类夹杂物在机加工时暴露于车轴表面而形成的缺陷;同时提出了通过氩封浇注的方法来减少二次氧化所带来的氧化物夹杂,从而提高了车轴的磁粉探伤合格率。     

集装箱拖车车轴断裂原因分析

集装箱拖车的车轴在旋挤压过程中出现开裂,采用电镜分析、金相检验等方法进行分析.结果表明,车轴所用原材料中存在严重的带状组织,在旋挤压的工作条件下便产生热轧裂级,最终导致所加工的车轴开裂.     

高炉上料车车轴断裂原因分析

高炉上料车车轴在使用过程中发生断裂。采用断口宏观形貌观察、化学成分分析和金相检验等方法对车轴进行了综合分析。结果表明：材料内部存在的大量非金属夹杂物成为裂纹源，为裂纹的产生提供了条件；另外机加工不当造成的应力集中加速了裂纹的扩展，以至在正常载荷条件下工作的车轴产生了断裂。     

轮对几何参数及踏面缺陷光电检测方法

提出了一种基于光电检测技术的车辆轮对综合参数自动检测方法。运用精密激光位移传感、CCD及数字图像处理技术,实现了轮缘厚度、轮缘高度、车轮直径等尺寸参数的非接触自动检测;再结合精密运动控制,以及车轴和圆周方向的快速激光扫描,实现了踏面擦伤和剥离等缺陷参数的分类和识别。实验结果表明,基于上述测量方法的检测系统,其尺寸参数测量精度为0.2mm,擦伤深度测量精度为0.1mm,剥离长度测量精度为0.5mm,能满足车辆段修现场使用的要求。     

基于STM32的客车轴报联网检测试验台设计

铁路客车的轴温报警装置是保障车辆运行安全的重要组成部分,是检测客车轴温的重要工具,轴温过高,极易引发行车安全问题.为了解决现有的轴温报警器不能进行联网功能检测的问题,本文设计了一种新型的铁路客车轴报检测联网试验台.本试验台通过将客车的轴温报警器设备进行联网通信,具有可直接检测客车轴温报警器系统联网通信功能,集中观测轴温报警器的测温状况以及温升报警功能,并能同时接入20台轴报控制显示器,将客车的轴温数据统一传输到主机中,检测人员通过对每台轴温报警器的数据进行分析,可判断出轴温报警器的整体性能,确保每台轴温报警器的可靠性,为行车安全提供了重要保障.     

Failure Analysis of Induction Hardened Automotive Axles

Rollover accidents in light trucks and cars involving an axle failure frequently raise the question of whether the axle broke causing the rollover or did the axle break as a result of the rollover. Axles in these vehicles are induction hardened medium carbon steel. Bearings ride directly on the axles. This article provides a fractography/fracture mechanic approach to making the determination of when the axle failed. Full scale tests on axle assemblies and suspensions provided data for fracture toughness in the induction hardened outer case on the axle. These tests also demonstrated that roller bearing indentions on the axle journal, cross pin indentation on the end of the axle, and axle bending can be accounted for by spring energy release following axle failure. Pre-existing cracks in the induction hardened axle are small and are often difficult to see without a microscope. The pre-existing crack morphology was intergranular fracture in the axles studied. An estimate of the force required to cause the axle fracture can be made using the measured crack size, fracture toughness determined from these tests, and linear elastic fracture mechanics. The axle can be reliably said to have failed prior to rollover if the estimated force for failure is equal to or less than forces imposed on the axle during events leading to the rollover.     

用低倍分析方法研究摩托车起动轴的断裂

采用低倍分析方法对断裂的摩托车起动轴进行了分析,分析结果表明,该起动轴由于与脚踏杆的内齿装配啮合连接不好,以至脚踏杆切入起动轴,进而导致起动轴断裂。     

Investigation into the causes of fracture in railway freight car axle

Railway axles are vital parts of railway. Their failure in the form of dynamic fracture is commonly of disastrous outcomes for railway vehicles. Accordingly, railway axles are designed to be highly reliable, while the maintenance system requires regular inspection in terms of crack initiation. However, due to complex exploitation conditions, complex stress state and multiple stress concentration, railway axles often experience fatigue failures. This occurrence has been studied in a large number of papers. This paper too sheds light on the causes of fracture occurrence in the axle of railway freight car for coal transport in a thermal power plant. Detailed analyses were conducted on the axle fracture surface and mechanical properties. Also, microstructure of the axle material, as well as on exploitation conditions and stress state was examined. Calculations indicated that, apart from working load impact, the influence of press fit joints, especially of the one between the labyrinth seal and the axle is of crucial importance for the analysis of railway axle stress state. The entire numerical–experimental analysis has shown that the considered axle failure was caused by inadequate maintenance, insufficient axle strength and adverse stress state in the railway axle critical cross-sections.     

桥梁动态称重迭代算法的理论与试验研究

桥梁动态称重(bridge weigh-in-motion,BWIM)能够以桥梁作为载体识别过往车辆的轴重。商用BWIM系统通常基于Moses算法,以桥梁的实测影响线对车桥实测动力响应进行轴重识别。然而,该算法的轴重求解方程是病态方程,在特定情况下轴重识别精度偏低。为解决这一问题,该研究提出桥梁动态称重迭代算法,通过Moses算法和实测影响线算法之间的反复迭代,修正病态的轴重求解方程。该研究介绍了桥梁动态称重迭代算法的原理,并进行了相关公式推导;基于怀化舞水五桥引桥的车桥动力试验,对比分析商用BWIM算法和桥梁动态称重迭代算法的轴重识别精度;并深入探讨影响线的选取对轴重识别精度的影响。研究表明,桥梁动态称重迭代算法能够在一定程度上提高轴重识别的精度,其最佳的基准影响线是实测均值影响线。     

CA1040P90L2轻型货车驱动桥设计

驱动桥由主减速器、差速器、驱动车轮的传动装置及桥壳等部件组成。分析了CA1040P90L2轻型货车驱动桥中各主要零部件的结构型式、基本参数选择与设计计算,并对各主要零部件进行了三维建模,给出了CA1040P90L2轻型货车驱动桥的三维设计,实现了三维装配仿真与运动仿真。通过驱动桥的设计实现了零部件的全参数建模。     

Procedure for reliable durability validation of train axles

The structural durability of wheelset axles depends on the operational loading as well as on the fatigue strength of axles. To validate an axle design the time‐varying stresses in individual critical areas of the axle, represented by their stress spectra, must be taken into account. The allowable stresses in individual axle areas depend both on the fatigue strength and on the spectrum of operational stresses. The procedure for the axle structural durability validation, presented in this paper, includes the numerical fatigue life estimation as well as the experimental durability approval. Also the influences of axle design, material properties and manufacturing technology on structural durability are discussed.     

M5-36-11 No.20.5风机轴断裂分析

采用宏微观检验、化学分析和显微硬度检测等方法对风机轴的断裂原因进行了分析。结果表明，该轴断裂是由于轴表面存在焊接缺陷，在旋转弯曲应力作用下产生应力疲劳开裂。     

车辆驱动桥噪声分析及试验研究

利用逆序法对驱动桥噪声信号的平稳性进行了验证，指出其噪声信号为非稳态信号。通过对6480型驱动桥的噪声功率、表面声强、表面声压、表面振动加速度以及相应的时频谱进行了全面、系统的测量和分析。研究结果表明：驱动桥噪声能量主要集中在400Hz-3800Hz范围内，驱动桥凸缘和后盖是驱动桥的主要噪声辐射源。驱动桥噪声产生的根本原因是主从动锥齿轮在传动轴的驱动下啮合时产生的啮合冲力和振动引起的；噪声产生的直接原因是驱动桥表面受到各种动态力的激励而产生的振动。因此如果要降低驱动桥噪声，必须从减振入手。     

齿轮轴断齿分析

齿轮轴运行近1a（年）后发生相邻两齿断裂。采用宏、微观检验以及硬度试验等方法对轴的断裂原因进行了分析。结果表明，齿轮轴断齿属于疲劳断裂。因齿轮箱供油不足，造成齿轮轴在高温状态下其强度和硬度急剧下降，导致齿轮轴断齿而失效。