浅析盘式制动摩擦片磨损过快的原因

本文简介了盘式制动摩擦片磨损过快的情况,分析了摩擦片的磨损量与车辆行驶里程之间的关系以及引起盘式制动摩擦片磨损过快的原因。     

东风康明斯车离合器摩擦片磨损过快的原因及预防

东风康明斯汽车采用单片式螺旋弹簧或单片式膜片弹簧离合器，该总成带有两级减振器和怠速减振器，能较好地衰减从传动系统传递来的扭转振动，只要正确地操作使用离合器，就可避免离合器摩擦片的非正常磨损。但从驾驶人反映的情况来看，存在离合器摩擦片磨损过快的现象。本文就东风康明斯汽车离合器摩擦片磨损过快的原因进行分析，并提出预防措施，以供汽车驾驶人和修理人员参考。     

奔驰轿车制动器摩擦片过薄报警系统的检查

奔驰轿车两前轮上装有车轮制动器摩擦片过薄报警系统,它能自动检测摩擦片的磨损程度。当车轮制动器上的摩擦片磨损到一定厚度时,报警指示灯闪亮,以提醒驾驶员更换摩擦片。现以奔驰280EL型为例,介绍其工作原理及故障检测方法。 如图1所示,该车摩擦片过薄报警系统是由带有传感器的特殊摩擦片、电子控制器和报警指示灯组成。传感器的短接线置入了该特殊摩擦片的一定深度处,当摩擦片磨损到只有2.0～2.2mm极限厚     

基于典型道路谱的汽车制动摩擦片寿命预测

文章基于能量磨损机理提出了一种汽车制动摩擦片磨损寿命预测的方法,对车辆制动安全性以及摩擦材料利用率的提升具有一定的现实意义。以车辆制动系统中的摩擦片为研究对象,在制动盘冷却试验基础上建立制动摩擦副热力学模型,旨在探明不同工况下摩擦副热力学特征的变化规律。根据能量磨损机理研究制动温度对材料磨损量的影响关系,结合温度分布特征与摩擦材料磨损率提出摩擦片磨损量的评价标准,建立制动摩擦片的磨损寿命预测模型。基于典型公路道路试验路谱的动力学参数进行摩擦片磨损寿命预测,与试验结果相比其磨损寿命预测具有较好的一致性,为汽车制动系统参数设计及制动摩擦材料寿命研究提供了指导依据。     

新款6T40变扭器锁止抖动的故障分析和解决方案两例

<正>案例一带有启停功能的新款6T40变速器在维修过程中，变扭器损坏是常见的故障之一。打开变扭器，通常会发现里面的锁止离合器上的摩擦片已经严重磨损了，甚至被完全磨光，导致锁止盘与变扭器前盖互相磨损的程度（图1）。对这类变扭器，很多变扭器的翻新厂在更换了摩擦片以后还会经常遇到返修，普遍反映替换的摩擦片不耐用，很快会再此磨损，或者又会出现锁止抖动的问题，目前这已成为很多变速器专修厂令人头痛的问题了。我们将从变扭器摩擦片和变速器的油路控制两个方面来分析这个问题的故障根源。     

叉车离合器摩擦片过早磨损的原因

近来有部分用户反映3.5t叉车离合器摩擦片磨损严重,摩擦片寿命不足2t叉车的一半。针对此问题,我们经过一段时间对用户跟踪调查,找到了过早磨损的原因。     

鼓式制动器摩擦片-鼓接触点确定方法及变化规律分析

分析了鼓式制动器鼓和摩擦片完全接触的原理,根据几何关系,并考虑鼓内表面和摩擦片外表面的尺寸公差、支撑销轴心的装配误差以及摩擦片表面磨损等因素,推导出一套确定鼓式制动器初始接触点和接触区域的公式.通过Matlab编程计算某款重型汽车鼓式制动器摩擦片-鼓的接触位置,绘制了接触区域随制动蹄角度位置而变化的曲线.分析表明鼓内表面和摩擦片外表面尺寸公差、支撑销轴心装配误差和摩擦片表面磨损对接触位置有重要影响,据此对它们提出相应的要求.     

盘式制动器热-应力-磨损耦合行为的数值模拟

本文中探讨了盘式制动器制动过程中摩擦片和制动盘之间的热负荷-接触应力-磨损耦合行为的数值模拟方法。首先建立了盘式制动器的有限元模型;然后研究了应力-磨损耦合分析的数值计算方法,并且模拟了摩擦片和制动盘的磨合过程;最后分别对热-应力耦合条件下和紧急制动工况下的摩擦片磨损行为进行了模拟。结果表明,所提出的模拟方法是有效的。     

奔驰轿车制动摩擦片过薄报警灯的故障排除

高级轿车的制动性能较稳定,故障甚低。为了减少车轮的拆装次数,有些高级轿车上装用能报警的车轮制动摩擦片。它能自动检测其磨损程度,当摩擦片磨损到只有一定厚度时,其上的传感器能自动使过薄报警灯亮,提示要换摩擦片。该装置由带传感器的特殊摩擦片,电子控制器和指示灯组成,在该特殊摩擦片的一定深度埋有一短接线,当摩擦片磨损到只有2.0～2.2mm极限厚度时,短线自动磨断;传感器立即把信号传至电子控制器,使红色指示灯发出告警信号。其结构示意图述后。 大多数奔驰轿车的仪表盘上有一个图标为|○|的     

奔驰G55 AMG车制动系统异常报警

<正>故障现象一辆奔驰G55 AMG车,累计行驶里程约为4万km,客户反映该车仪表盘上出现"Brake wear"的字样,显示制动摩擦片已磨损到极限。故障诊断接车首先验证故障现象,发现接通点火开关后踩下制动踏板,仪表盘上就立即出现"Brake wear"字样(图1)。接着检查了前后制动摩擦片,发现制动摩擦片磨损很少,     

基于频率法的索力测量系统

为了在工程现场快速方便地检测斜拉桥的拉索索力,依据随机振动法索力检测原理,开发了一种新型的索力测量系统。通过对随机振动法索力检测方法的概述,介绍了该系统的性能、硬件结构和软件模块,并重点阐述了通过数字滤波抑制快速傅里叶分析(FFT)的混频现象、自动扫描确定主振频率和提高索力计算精度的方法和措施。索力测量系统以AT89C55WD单片机(SCM)为平台,集成了电荷放大器、信号分析仪和计算器的相关功能。在工程现场,只需输入少量参数,拉索振动信号采集、信号的快速傅里叶分析和对应的索力计算即可在线自动完成。     

A vehicle type-based approach to model car following behaviors in simulation programs (case study: Car-motorcycle following behavior)

Traffic simulation models often neglect the important role of motorcycles and assume a flow of various combinations of cars. This paper addresses how much different would be the behavior of a car driver while following a motorcyclist compared to cases in which a car follows another car, along with a segment of an urban highway in the non-congested flow. Recognition of such a difference might help to develop existing simulation models and to improve the behavior of car drivers in such a way to lead to lower accidents with motorcycles. To reach the goal, a GHR (Gazis-Herman-Rothery) model for car following is applied and data have been collected by video cameras during 15?min time intervals in three different days. Analysis of 198 car-motorcycle and 374 car-car following observations has indicated that when a car driver follows a motorcycle, keeps a higher headway (about 10?m in the low speed) with a lower acceleration/deceleration in comparison with the situation in which car driver follow another one. It means that the behavior of the follower car driver would be more cautious compared to situations in which a car driver follows another one, especially in space headways <10?m. In addition to main findings of the paper for developing a more realistic simulation program, the paper also addresses that in cases when the required safe space between a car and a motorcycle would be endangered, a warning message could be generated for the car driver (by implementing an in-veh ITS technology) to warn driver about keeping a safe distance.     

面向交通枢纽的车辆三维真实感实时仿真

为分析和解决城市交通拥挤问题并提高城市道路利用率提供可行的途径,提出了一种面向交通枢纽的车辆运行仿真方法,通过场景、道路与车辆的三维动态建模,实现交通枢纽交通状况的实时真实感仿真.首先,提出了基于道路关键点连接网络模型表示交通枢纽的通行道路.其次,基于粒子系统实现车辆的动态运行实时仿真,并采用基于空间剖分的车辆碰撞检测方法对车辆运动控制算法进行了优化.最终,通过对路段的动态观测和反馈机制实现车辆行驶路线的规划和调度.实验结果表明,本文提出的方法可以生动直观地呈现实际路面的交通状况,并且能以较为流畅的帧速率实现交通场景的动态仿真.     

Dynamic analysis of a pantograph-catenary system using absolute nodal coordinates

The dynamic interaction between the catenary and the pantographs of high-speed trains is a very important factor that affects the stable electric power supply. In order to design a reliable current collection system, a multibody simulation model can provide an efficient and economical method to analyze the dynamic behavior of the catenary and pantograph. In this article, a dynamic analysis method for a pantograph-catenary system for a high-speed train is presented, employing absolute nodal coordinates and rigid body reference coordinates. The highly flexible catenary is modeled using a nonlinear continuous beam element, which is based on an absolute nodal coordinate formulation. The pantograph is modeled as a rigid multibody system. The analysis results are compared with experimental data obtained from a running high-speed train. In addition, using a derived system equation of motion, the calculation method for the dynamic stress in the catenary conductor is presented. This study may have significance in providing an example that a structural and multibody dynamics model can be unified into one numerical system.     

A study on a dynamic model of a vehicle simulator with 6 DOF for the Korean tilting train

This article presents a dynamic model of a railway vehicle for the development of a 6-DOF (degrees of freedom) tilting-train simulator. It will be used to verify the tilting-electronics and tilting-control algorithm that are to be applied to the Korean tilting train. It is composed of 6 electrically driven actuators, a track generation system, a graphic user interface, and a visualization system with a 1600-mm-diameter dome screen. Each system shares the data by means of Ethernet network in real time. In this study, a train model of 9-DOF with a force generation system to tilt the train body has been used. Dynamic analysis for the straight track running and curve negotiation of a railway vehicle can be performed in the model. A verification study for the application of the model to the simulator has been conducted on curving tracks with different radii.     

考虑溶洞空间形态的路基岩溶顶板稳定性分析方法

岩溶路基随岩溶地区交通工程建设的快速发展而越来越普遍,如何评价岩溶路基稳定性成为岩溶区路基设计与施工的关键问题之一。针对目前路基岩溶顶板稳定性分析的不完善性,考虑溶洞形成过程中岩溶顶板所具有的空间形态特征,首先,将路基下伏岩溶顶板简化为固支梁、抛物线拱、圆拱与固支双向板等承载模型,以此进行路基岩溶顶板稳定性分析,并采用结构力学分析理论分别建立不同模型的路基岩溶顶板抗弯最小安全厚度计算方法;其次,通过典型案例的影响因素敏感性分析,揭示岩溶顶板最小安全厚度随溶洞顶板矢高、跨度、岩石抗拉强度与上覆荷载的变化规律,探讨路基岩溶顶板破坏模式的控制性因素及其影响规律,确定岩溶路基稳定性分析的基本原则;然后,基于岩溶地区地质勘察信息提出路基岩溶顶板稳定性分析过程,建立考虑溶洞空间形态特征的路基岩溶顶板稳定性分析方法;最后,通过工程实例计算分析验证所提方法确定的路基岩溶顶板稳定性评价结果的合理性与有效性。研究结果表明：岩溶顶板按何种模式破坏不仅与破坏形式有关,还与溶洞形态及其矢高密切相关,石灰岩抗拉强度同样影响较大,工程设计与稳定性评价时应基于勘测数据分析各种破坏模式,以便使设计或评价结果更接近实际情况。     

Real-time implementation of a traction control algorithm on a scaled roller rig

Traction control is a very important aspect in railway vehicle dynamics. Its optimisation allows improvement of the performance of a locomotive by working close to the limit of adhesion. On the other hand, in case the adhesion limit is surpassed, the wheels are subjected to heavy wear and there is also a big risk that vibrations in the traction occur. Similar considerations can be made in the case of braking. The development and optimisation of a traction/braking control algorithm is a complex activity, because it is usually performed on a real vehicle on the track, where many uncertainties are present due to environmental conditions and vehicle characteristics. This work shows the use of a scaled roller rig to develop and optimise a traction control algorithm on a single wheelset. Measurements performed on the wheelset are used to estimate the optimal adhesion forces by means of a wheel/rail contact algorithm executed in real time. This allows application of the optimal adhesion force.     

Multiphysic modelling of railway vehicles equipped with pneumatic suspensions

This article presents a multidisciplinary approach of railway pneumatic suspension modelling: both multibody and pneumatic aspects are taken into account. The work aims at obtaining a realistic model of the secondary suspension and coupling it with a multibody model of a train. Various components of the pneumatic circuit such as bellows, tanks, pipes and valves are taken into account. The article focuses on the bellow-pipe-tank subsystem for which several modelling approaches are presented and compared. Differences between differential and algebraic models are highlighted, and an application-dependent choice between them is suggested. A complete model of the pneumatic circuit is then obtained and coupled with a multibody model of the train. As a result, the behaviour of a suburban train equipped with a pneumatic secondary suspension is analysed, in particular undesired oscillating motions which affect the comfort. Topological modifications and improvements of the suspension are also investigated and discussed.     

Influence of some vehicle and track parameters on the environmental vibrations induced by railway traffic

A study is performed on the influence of some typical railway vehicle and track parameters on the level of ground vibrations induced in the neighbourhood. The results are obtained from a previously validated simulation framework considering in a first step the vehicle/track subsystem and, in a second step, the response of the soil to the forces resulting from the first analysis. The vehicle is reduced to a simple vertical 3-dof model, corresponding to the superposition of the wheelset, the bogie and the car body. The rail is modelled as a succession of beam elements elastically supported by the sleepers, lying themselves on a flexible foundation representing the ballast and the subgrade. The connection between the wheels and the rails is realised through a non-linear Hertzian contact. The soil motion is obtained from a finite/infinite element model. The investigated vehicle parameters are its type (urban, high speed, freight, etc.) and its speed. For the track, the rail flexural stiffness, the railpad stiffness, the spacing between sleepers and the rail and sleeper masses are considered. In all cases, the parameter value range is defined from a bibliographic browsing. At the end, the paper proposes a table summarising the influence of each studied parameter on three indicators: the vehicle acceleration, the rail velocity and the soil velocity. It namely turns out that the vehicle has a serious influence on the vibration level and should be considered in prediction models.     

Theoretical method for predicting the weight reduction rate of a box-type car body for rolling stock by material substitution design

In this paper, a theoretical approach is suggested for predicting the structural performances and weight reduction rate of a car body with a box-type section when its material is substituted with a lightweight material for weight saving. For the material substitution design of a car body for rolling stock, bending, axial, and twisting deformations should be considered at constant stiffness and strength conditions. To compare the weight reduction effects on different material applications, some new indices were derived from a structural performance point of view. The derived indices provide good measures to estimate weight reduction by material substitution design and can be effectively applied to the conceptual design of a car body.