平板式和滚筒反力式制动检验台检测影响因素对比分析

通过对平板式制动检验台和滚筒反力式制动检验台工作原理的分析和实车试验的方法的研究,分析各相关因素对平板式和滚筒反力式制动检验台检测结果的影响。试验表明:载荷和附着率对平板式和滚筒反力式制动检验台检测结果都有较大影响,并且附着率对平板式制动检测台检测结果影响更明显。针对相关因素对两种试验设备检测结果的不同影响,在选用制动检测方法时有较好的参考作用。     

车辆制动性能检测实践中的经验总结

本文从对ABS制动车辆、多轴车制动动力检测两方面给出了制动性能检测过程中需注意的问题,并创新出利用滚筒反力式制动检验台对多轴车检测制动协调时间的方法。同时也指出了平板式制动试验台在应用中的优、缺点。本文具有很强的现实意义。     

检测汽车制动性能的方法

汽车制动性能是衡量汽车安全的一个重要指标,它反映汽车在行驶过程中制动的能力。目前国内普遍采用两种检测方法:①试验台检测法;②路测法。由于路测法在测试过程中会受到路况、天气、驾驶员反应能力等客观因素的影响,故这种方法有一定的局限性。试验台检测法可采用平板式制动检验台和滚筒式制动检验台。着重讨论滚筒式制动检验台检测方法的设计与优化。     

多轴驱动车辆制动检测可行方法的对比分析

为解决多轴驱动车辆在定期审验中制动性能检测困难的现状,基于平板式和滚筒反力式制动检验台的工作原理和基本结构,提出几种多轴驱动车辆制动性能检测的可行方法,并进行对比分析和论证,为多轴驱动车辆制动性能的检测提供理论参考.其中,左右滚筒异向同步驱动零差速法可以满足多轴驱动车辆定期审验制动性能检测的要求,且该方法方便、快捷、准确.     

滚筒反力式制动检测台动态校准研究

针对滚筒反力式制动检测台传统检定方法的不足进行动态校准技术研究,设计开发一套基于离心式动态力标准机的制动台校准装置,该装置由伺服电机驱动多组离心机构做圆周转动,将可溯源的向心力集中输出,以此作为参考制动力加载到制动检测台,进行工况条件下动态校准。通过制动检测台现场实验,研究校准装置和制动检测台的测量重复性与动态特性,分析相关数据和结果。研究发现:离心式动态力标准机在阶跃激励下能在200 ms内最大输出3.8 kN力,力值标准差不大于5.0 N或小于1%,动态力响应曲线有13%～19%超调量;制动检测台的测量结果重复性较差,在力值上升阶段最大标准差达到280 N,终值阶段的标准差亦达到3%,而且测量值曲线的超调量只有1%～2%,峰值时间滞后约100 ms。研究表明,制动检测台数据处理存在过度平滑的失真。     

平板式制动台制动力测量不确定度评定

采用标准测力仪对平板式制动台制动力进行测量,分析和评定测量不确定度.     

平板式制动试验台和滚筒式制动试验台的结构和作用原理

汽车制动性能是确保汽车安全行驶的重要条件。为了保障在用汽车的行驶安全,我国公安车管部门和交通车辆管理部门规定,在用汽车必须进行年度审验,以保证在用汽车的行驶安全。目前,我国使用的制动检测设备主要有平板式制动试验台和滚筒式制动试验台。本文详细介绍了制动台的结构和作用原理,以期达到提高广大司机师傅对汽车制动性能的了解。     

两种机动车制动性能检验设备检验结果的对比

一、问题的提出 国家标准GB7258—2004《机动车运行安全技术条件》规定，机动车制动性能的检验有路试制动性能检验方法和台试制动性能检验方法。其中，台试检验方法易于操作、效率高，并实现了自动化检测，所以在日常的机动车检验中普遍采用。路试检验方法仅在不宜用台试检验方法时采用，或在对台试制动性能检验结果有质疑时作为解决争议的一种仲裁检验方法。GB7258—2004中对台试检验机动车制动性能规定，当用台试检验方法检验行车制动性能时，对于汽车在空载状态下，要求制动力总和与整车重量的百分比大于或等于60％，并推荐了两种检验设备，即滚筒式制动检验台和平板式制动检验台。     

汽车制动性能测试系统的设计

汽车制动性能是汽车安全性的主要指标之一,作为汽车性能检测的最重要指标之一,它直接影响交通运输效率,和汽车速度性能的发挥,并且关系到乘员、车辆和行人的安全,因此车辆制动性能的好坏是影响安全行车的一个重要因素。测试汽车制动性能的方法分两大类：（1）台测法;（2）路测法。其中台测法因其受外界环境影响小而广泛使用。台测法按原理不同,又可分为反力式和惯性式两类。本文就惯性式进行研究和设计,为汽车制动性能检测的台式法设计提供一定参考。     

浅谈厂内机动车辆制动性能的两种检测方法

本文介绍了通过制动踏板向下运动实现制动的厂内机动车辆制动系统的动作全过程,并对制动性能两种检测方法所测的制动距离与车辆实际制动距离存在误差的原因进行了分析,最后给出了有效的降低检测误差的方法。     

Temperature and torque determination in brake drums

Simulation of temperature distribution in a brake drum and determination of drum brake torque has been carried out using finite element methods. The simulated temperature distribution and the brake torque determined were compared with observations carried out using an inertia dynamometer with a data-logging system. There is good agreement between the predicted temperature distribution and the brake torque determined with the test results on the dynamometer.     

车辆制动检测实验台架的研制开发

利用转鼓实验台,自行设计了的车辆制动检测实验系统,包括机械加工部分以及数据采集和处理系统,可以对车辆制动时的主要参数进行测量,并由此计算出其它参数.同时结合开发的防抱死制动系统,在此检测台架上进行了相关实验,达到了理想的效果,为制动实验提供了一套实用的方法.     

鼓式制动器制动不稳定时变特性分析

由于工作环境复杂多变,制动器工作不稳定而导致振动和噪声,鼓式制动器制动时的温度变化对制动不稳定性影响较大,研究制动不稳定性影响因素及其制动不稳定时变特性具有实际工程意义。基于鼓式制动器四自由度接触模型,分别在Hypermesh和ABAQUS中建立鼓式制动器制动鼓和制动蹄总成模型与摩擦制动接触模型并进行试验验证;通过热机耦合动态分析,研究制动鼓温度对制动应力的影响;分析弹性模量和热膨胀系数对鼓式制动器制动不稳定时变特性的影响。分析表明：制动不稳定性是摩擦力耦合所致;制动过程中制动鼓温度与应力相互作用且均先快速上升后缓慢下降;鼓式制动器制动不稳定时变特性主要体现在不稳定模态个数及不稳定倾向系数（tendency of instability, TOI）值的变化,制动温度变化导致弹性模量变化,引起不稳定模态个数和TOI值略有变化,弹性模量对鼓式制动器制动不稳定时变特性影响较小;制动温度变化导致热膨胀系数变化,引起不稳定模态个数和TOI值先大幅降低后略有升高,热膨胀系数对鼓式制动器制动不稳定时变特性影响较大。研究结果对改善汽车制动声品质具有一定指导意义。     

颗粒阻尼技术在制动鼓减振方面的应用研究

颗粒阻尼器具有不改变结构形状、附加质量小等特点,在其他被动阻尼常失效的恶劣环境下仍具有良好的减振效果。然而,传统的颗粒阻尼器设计通常依靠试验的方法。研究了颗粒阻尼技术在汽车制动鼓减振降噪领域的应用,基于离散元和有限元的耦合方法分析颗粒阻尼在汽车制动鼓上的应用,使颗粒阻尼减振器在旋转结构上的研究成为可能。结果表明:颗粒阻尼技术在汽车制动鼓减振降噪领域的应用是可行的,仿真结果与试验结果具有很好的一致性。     

A reliability-based robust optimization design for the drum brake using adaptive Kriging surrogate model

To decrease random parameters’ influence on the drum brake reliability, the reliability-based robust optimization design (RBROD) of the electric vehicle brake is proposed. Based on the assumption that the maximum temperature of the brake cannot exceed the allowable temperature, a performance function model of thermal–mechanical coupling reliability of drum brakes is established by the adaptive Kriging method, and the analysis of reliability sensitivity and RBROD are conducted. The accuracy of the proposed model is verified by temperature measurement experiment under emergency braking condition. The robust optimization design improves the drum brake reliability to 0.99998 and reduce the influence of the design parameters on the reliability, with the absolute values of the reliability sensitivity and the weight of the drum brake are significantly smaller. Therefore, the objectives of reliability design, robustness design, and optimization design are simultaneously achieved by the proposed methods. Besides, the relative error of the proposed method is 0.373%, the number of function evaluations is 39, and the comparison with four meta-model methods show that the proposed method holds high-accuracy and high-efficiency. This study provides a high-precision theoretical explanation for the robust optimization design of drum brake.     

Thermomechanical Behavior of Brake Drums Under Extreme Braking Conditions

Braking efficiency is characterized by reduced braking time and distance, and therefore passenger safety depends on the design of the braking system. During the braking of a vehicle, the braking system must dissipate the kinetic energy by transforming it into heat energy. A too high temperature can lead to an almost total loss of braking efficiency. An excessive rise in brake temperature can also cause surface cracks extending to the outside edge of the drum friction surface. Heat transfer and temperature gradient, not to forget the vehicle's travel environment (high speed, heavy load, and steeply sloping road conditions), must thus be the essential criteria for any brake system design. The aim of the present investigation is to analyze the thermal behavior of different brake drum designs during the single emergency braking of a heavy-duty vehicle on a steeply sloping road. The calculation of the temperature field is performed in transient mode using a three-dimensional finite element model assuming a constant coefficient of friction. In this study, the influence of geometrical brake drum configurations on the thermal behavior of brake drums with two different materials in grey cast iron FG200 and aluminum alloy 356.0 reinforced with silicon carbide (SiC) particles is analyzed under extreme vehicle braking conditions. The numerical simulation results obtained using FE software ANSYS are qualitatively compared with the results already published in the literature.     

鼓式制动器结构振动尖叫问题综述

制动尖叫问题是当今工程领域研究热点。对近期鼓式制动器结构振动尖叫问题的研究工作进行回顾和总结,重点在于了解系统的动态特征及具体解决措施,希望能为工程人员解决实际问题提供方案。     

Study on the limit cycle oscillation of the drum brake non-linear vibration model at low frequency

A 5-degree non-linear dynamic model is presented to describe the low frequency vibration of drum brake. The centre manifold theory is applied to reduce the system at the Hopf bifurcation point. Through the calculation of normal form of the reduced system at the Hopf bifurcation point, the limit cycle oscillations (LCOs) amplitude is obtained. By this method, the effect of the drum brake parameter on LCO amplitude is studied, the law of the LCOs amplitude varying with systematic parameters is obtained.     

基于解析模型的气制动系统泄漏故障诊断研究

针对客车气压制动系统中存在的泄漏故障的问题,提出了一种基于解析模型的客车气压制动系统泄漏故障诊断的方法。通过对气制动系统中的关键部件制动总阀及制动气室的工作状态进行分析,建立了正常状态下的客车气制动系统制动气室压力特性的理论模型,该模型能够预测制动过程中制动气室中的瞬时气压值。搭建了整车气压制动系统模拟试验台,该试验台可针对整车制动系统进行制动性能模拟试验。在模拟制动过程中对制动气室中气压变化量进行测量,将归一化后的试验值与理论值进行比较,对气制动系统有无泄漏故障的存在进行了诊断。试验结果表明,该方法能很好地对气制动系统泄漏进行故障诊断。     

Thermal seizures in automotive drum brakes

In automotive industry, drum brake system is used on two types of wheels: cast and spoke. Brake drum, brake panel and brake drum liner are important components of the brake system. Failures of these components observed during high-g braking on spoke wheels of a motorcycle are reported and systematically analyzed in this paper. The brake drum and the panel were found to have seized during high speed brake applications. Excessive wear on the drum liner made of cast iron was also observed. Metallurgical analysis (chemical analysis, hardness test and microstructure analysis) of the liner revealed that excessive wear on the liner was not due to any change in material properties. Hence, further steps were taken to investigate the problem. An experimental testing methodology was developed to simulate these failures. For the same material, testing conditions, and design specifications of cast and spoke wheels, no failure was observed in the cast wheels. This unusual failure was further investigated using three-dimensional steady state finite element analysis (FEA) of both cast and spoke wheels. The methodology adopted for determining the thermal and structural boundary conditions have been described in detail. Energy balance methodology was employed to determine the heat flux values on the drum liner. The structural boundary conditions are determined experimentally and validated with FEA. The predicted temperature from FEA for cast and spoke wheels compares reasonably well with the experiments. It was found that the failure of the brake system in the spoke wheels was due to excessive thermal expansion of the brake panel and the drum beyond the specified limit. An optimum range of labyrinth clearance between the brake drum and the brake panel was recommended for the brake system of cast and spoke wheels.