【作者】 郭鸿瑞；

【导师】 余强；

【作者基本信息】 长安大学 ， 车辆工程， 2008， 硕士

【摘要】 近年来我国道路交通事故逐年上升,尤其是山区长大下坡路段,群死群伤的重、特大交通事故时有发生。车辆制动系统热衰退是引发山区交通事故的一个重要原因。论文针对公路特殊路段制动热衰退的道路交通事故特点,主要研究了在不同车速下长大下坡路段制动过程间隙的温降过程,以期从温降的角度提出避免“热衰退”的措施。论文首先通过对陕西境内咸永一级公路马家坡路段、蓝小路路段行驶车辆进行了调查分析,确定了典型车辆,并选用该典型车辆的后桥鼓式制动器作为论文研究对象,从传热学出发,研究了鼓式制动器的生热、散热过程,应用有限单元法建立鼓式制动器温降有限元模型。借助虚拟样机技术软件ANSYS对鼓式制动器在不同车速下的温降过程进行了数值模拟,得出鼓式制动器温度场的分布状况。在试验设计原则及制动性能规范要求的指导下,论文进行了鼓式制动器温降台架试验和道路试验研究。在试验过程中,模拟车辆在不同车速下的行驶工况,通过分析采集到的温降数据,最终得到了鼓式制动器温降的变化曲线。经过鼓式制动器温降台架试验和道路试验验证,鼓式制动器有限元仿真模型是比较合理的。定量分析了降温时间、车速、鼓式制动器降温起始温度、环境温度、鼓式制动器材料的变化对制动器温降的影响。文中通过对计算结果进行的详细分析,得出了一些有价值的结论。这些结论对避免鼓式制动器“热衰退”及其合理的使用都具有一定的现实意义。更多还原

【Abstract】 In recent years, the traffic accidents in road are increasing year by year. Particularly, in long downhill mountains, serious traffic accidents occur from time to time. The hot recession of braking system of Vehicle is an important cause of traffic accidents in mountain. Aiming at the characteristics of road traffic accidents of brake failure on special section of highway, the process of temperature drop during the gap between the breaking on the long downhill under different vehicles velocity is mainly studied, for putting forward the measures to avoid "hot recession" from the temperature drop standpoint.Firstly, through the diagnoses on vehicles traveling between the section of Majiapo and Lanxiao of A road in Shaanxi Province, typical vehicle is confirmed, and its rear drum brake is selected as research object in the paper. On the basis of the theory of heat transfer, the process of heat’s creating and dissipating is analyzed detailed, and the mathematics model of temperature drop calculation is built. ANSYS is used for simulating the temperature drop process of the braking drum in different velocity. And the temperature distribution of drum is obtained.Under the guidance of principles of the trial design and braking performance specifications, the bench test and simulation test on the road of temperature drop of drum brake is researched. During the process of trial, the traffic conditions of vehicles are simulated in different speed, and eventually the curve of temperature drop of drum brake is obtained through the collection of data about temperature drop.The finite element simulation models of drum brake are proved to be relatively reasonable by the verification of the bench test and simulation test on the road of temperature drop of drum brake. The impact of the cooling time, speed, the initiative cooling temperature of drum brake, ambient temperature, and the material of drum on temperature drop is analyzed quantitatively.Some valuable conclusions have been gained by detailed analysis of the results. The conclusions have certainly practical significance for avoiding“hot recession”of drum brake and its rational use.更多还原