【作者】 单欢乐；

【导师】 周仲荣；

【作者基本信息】 西南交通大学 ， 机械设计及理论， 2012， 硕士

【摘要】 摩擦噪声是指因摩擦而发出的一种频率和声压级都不规则变化的声音,摩擦噪声与摩擦振动一起构成了阻碍许多摩擦系统在工业上正常应用的严重问题,并大大降低这些系统的使用寿命、工作效率等,如人工关节、制动系统、轮轨系统、车床切削系统等等。摩擦界面特性是影响摩擦噪声的关键因素,因此,通过研究摩擦界面特性的改变如何影响摩擦噪声,探索新的途径来进一步研究摩擦噪声的产生机理,这将对找到合适的方法来抑制摩擦噪声具有重要的指导意义。本研究主要是通过在制动盘铸铁样品表面加工沟槽形表面织构,并对其进行摩擦噪声试验,研究摩擦界面特性的改变如何影响界面摩擦学行为以及摩擦噪声特性。用电加工方法在制动盘蠕墨铸铁材料表面加工出沟槽形表面织构(沟槽深度30μm、宽度150μm、间距为500μm)。摩擦学试验在CETR-3多功能摩擦磨损试验机上进行,采用直径10mm的Si3N4陶瓷球为对磨球,采用球面-平面接触方式,变化法向载荷(3N、5N、10N、20N、40N)和往复滑动频率(0.2Hz、0.3Hz、0.5Hz),对沟槽形织构表面和光滑表面进行往复摩擦磨损试验,并采集摩擦过程中的振动加速度和摩擦噪声声压。采用等效声压级、相干函数及自功率谱等不同的信号处理方法,对摩擦噪声及振动信号进行分析,研究沟槽形表面织构对摩擦系统的振动及噪声的影响。同时,通过采用光学显微镜和轮廓仪对样品的磨损特性进行分析,研究沟槽形表面织构如何影响界面的摩擦学特性。最后把两者结合起来,从摩擦学角度对沟槽形表面织构如何影响摩擦噪声进行了解释。针对本研究所选取尺寸的沟槽形织构,主要获得一些结论：1.沟槽形织构表面产生的摩擦噪声的时间历程曲线不同于光滑表面。织构表面产生的摩擦噪声常常发生于往复滑动的2个行程中,而光滑表面只在往复滑动的某一行程中产生摩擦噪声。2.沟槽形织构表面较光滑表面更易产生摩擦噪声,且产生的摩擦噪声强度较高。3.沟槽形织构表面产生摩擦噪声的时间明显较光滑表面的早,且其主频率成分较多,这初步可归因于织构表面的沟槽会导致往复滑动过程中摩擦力频率成分增多,增大了摩擦力频率与系统固有频率耦合的概率,并引起系统的多阶振动。4.沟槽形织构表面比光滑表面具有较高的摩擦系数和耐磨性,沟槽形织构的存在明显地改变了接触界面摩擦磨损行为(排屑行为)和摩擦噪声特性,但摩擦系数和摩擦噪声之间目前还未能建立起良好的对应性。更多还原

【Abstract】 Friction noise with irregularly mutative frequency and sound pressure level is caused by the friction. In the industry, friction noise and vibration are considered to be greatly against the normal application of many friction systems and significantly reduce their service life and working efficiency, such as artificial joints, brake systems, wheel-rail system, machining systems, etc. Friction interface properties is one of the key factors for the friction noise. Therefore, the generation mechanism of friction noise is studied by investigating the influence of changing friction interface properties in this study. This will have a guiding meaning to find a good way to reduce and suppress friction noise.The influence of the change of friction interfereproperties on friction noise was investigated by machining grooved surface texture on braking disc materials (sample). Grooved surface texture (30μm in depth,150μm in width and500μm in pitch) was manufactured on the surface of vermicular graphite cast iron flat (brake disc material) by electromachining. Tribological tests of the grooved surface and smooth surface samples were carried out by using CETR-3multifunctional tribometer, different normal loads of3N、5N、 ION、20N、40N and reciprocating sliding frequencies of2Hz、0.3Hz、0.5Hz were used. Si3N4ceramic ball with10mm diameter was used as counterface ball and a ball-on-flat configuration was adopted. Both the vibration acceleration signal and frictional noise signal were collected during the tribological tests. Different signal processing methods including equivalent sound pressure level, coherence function and auto power spectrums were used to evaluated the vibration and noise signals. The effects of grooved surface texture on the vibration and noise properties of the friction system were studied. Moreover, the wear properties of the samples are evaluated by optical microscope and profilometer to reveal the influence of the grooved surface texture on friction interface properties. Finally, the influence of the grooved surface texture on friction noise was discussed from the viewpoint of tribology. Accordingly, the main conclusions can be drawn as following which are applicable only to the grooved surface texture adopted in this work:1. Time process curves of the friction noise of the groove-textured surface was different from those of the smooth surface. The friction noise of the groove-textured surface usually appeared in both strokes of reciprocating sliding. However, the friction noise of smooth surface normally appeared in just one stroke of reciprocating sliding.2. It is easier for the groove-textured surface to generate the friction noise compared to the smooth surface and with higher noise intensity. 3. Friction noise was prone to occur earlier for the groove-textured surface compared to the smooth surface, and more complex frequency components were found for the the groove-textured surface. This can be attributed to that the existence of grooved surface texture caused more components of the friction frequency during the reciprocating sliding. The increase of the friction frequency components would increase the probability of the coupling of the friction frequency and natural frequency of the system, and finally caused the vibration of multi-frequency of the system.4. The groove-textured surface adopted in this work exhibited higher coefficient of friction and wear resistance as compared to the smooth surface. The existence of grooved surface texture changed the fiction and wear behaviors as well as friction-induced vibration and noise properties of the frictional surfaces, but their corresponding relationship is not good.更多还原