【作者】 郑华；

【导师】 周仲荣； 陈光雄；

【作者基本信息】 西南交通大学 ， 机械设计及理论， 2004， 硕士

【摘要】 本论文对平面-球面接触条件下的金属往复滑动摩擦噪声现象进行了试验研究。主要试验内容有：(1) 采用两种目前常用于机车车辆上的闸瓦作为平试件材料进行摩擦噪声试验；(2) 进行了两种不同位移滑动规律下的往复滑动摩擦噪声试验；(3) 通过改变位移的幅值和频率来进行不同滑动速度下的摩擦噪声试验；(4) 使用激光共焦扫描显微镜(LCSM)及光学显微镜(OM)等设备对摩擦噪声出现时的平试件及对磨球试件的磨痕形貌进行了仔细观察，采集了相应的振动加速度、噪声声压等动态信号，记录了摩擦尖叫声压的历程。通过对试验结果的分析，进一步探讨了摩擦噪声现象及其与磨痕形貌的关系。 首先，记录并分析了不同试验条件下摩擦噪声自发生起历经5000次循环时声压级变化的大致历程。结果表明：一般地，摩擦噪声声压级均会经历增大、减小和稳定三个基本阶段，滑动速度对其影响比较显著，试验材料、位移变化规律及其它参数等对摩擦噪声初次出现时所经历的往复摩擦循环次数的影响不大。 其次，对不同试验条件下有摩擦尖叫噪声时的平试件及对磨球试件磨痕的形貌进行观察，结合有关动态信号，比较了摩擦噪声发生区域的形貌，试图把形貌特征及其变化与噪声声压大小联系起来。结果表明，磨痕形貌中的剥层磨损，犁沟可能对摩擦噪声声压有影响。另外，有意义的是，在球试件磨痕中部观察到一道坎节及其两侧形貌的明显差异。这为解释往复滑动摩擦噪声只在向上行程末期发生的原因拓宽了视野。 论文中还对比了正弦波和三角波滑动规律下的摩擦噪声现象及相应的磨痕形貌；分析了使用不同闸瓦材料时的摩擦噪声现象和磨痕形貌。结果表明：滑动规律的不同似乎对尖叫发生的时间有影响，而噪声声压大小似乎受滑动规律及闸瓦材料的影响不大；但这些条件的变化对磨痕形貌的影响看起来是比较明显的。 最后，综合上面的有关分析，结合摩擦学与热力学知识，尝试解释了球试件磨痕形貌特点的形成原因及其在摩擦噪声只在向上行程末期发生的过程中所起的作用。更多还原

【Abstract】 Experimental investigations are carried about friction-induced noise emitted by a flat specimen rubbing against a ball specimen under metal reciprocating sliding in this dissertation. Two kinds of pad materials that are generally applied in railway vehicles were subjected to squeal-forming tests. Different velocities or waveforms of reciprocating sliding are applied. Detailed observations of the worn scars after interrupting the tests are conducted by means of a laser confocal scanning microscope (LCSM) and optical microscope. Dynamic signals of the vibration acceleration and sound pressure of friction-indued noise are picked up and analyzed.At the first, signals of friction-induced noise from the beginning to cycle 5 000 under different test conditions are recorded and analyzed. The result shows that the sliding speed has a distinct influence on the sound pressure of friction-induced noise and that friction materials, reciprocating sliding displacement waveform and other test parameters have a very limited influence on the number of cycles when the friction-induced noise is initially generated.Secondly, Detailed observations of the surface topography of the worn scars of the flat specimen with squeal and matched ball specimen formed under different test conditions are performed, which is mainly introduced in the 4th chapter. The relation between the topography characteristics such as plowing grooves and adhesive asperities and sound pressure level of friction-induced noise is investigated. Significantly, it is found that there is a protruding crack strip in the vicinity of the centre of ball specimen scar and that there is a clear difference in surface topography between two sides of the strip. This difference seems to be applied to explain the cause why the squeal only occurs in the end of the upward-stroke under reciprocating sliding.In this dsssertation, the friction-induced noise phenomena and surface topography related to sine waveforms of reciprocating sliding displacement are compared with those corresponding to triangle waveforms. The noise and topography formed by using different flat specimen materials are alsoinvestigated. The result shows that different waveforms of reciprocating sliding displacement only have an influence on the number of cycles when squeal initially occurs. Whereas the sound pressure level seems not to be correlated with waveforms of reciprocating sliding displacement and flat specimen materials. However, when thses conditions are changed, it is found that there is a clear change in the surface topography.Lastly, the formation mechanism of the special topography of ball specimens and its effect on squeal only occuring in the end of the upward stroke are discussed and explained in view of tribo-thermo dynamics.更多还原