【作者】 徐蕾；

【导师】 朱真才；

【作者基本信息】 中国矿业大学 ， 机械设计及理论， 2010， 博士

【摘要】 衬垫是摩擦式提升机的关键部件,其性能的优劣直接关系到提升机的工作能力、提升效率和安全可靠性。近年来,有关提升钢丝绳与衬垫之间摩擦学问题的研究均在低速状态下进行,并未涉及重载高速滑动这一极端工况。当出现超载提升等意外因素引起的非正常滑动时,大量摩擦热积聚在衬垫表面,造成衬垫温升急剧变化,从而导致其摩擦因数及耐磨性急剧下降,引发恶性事故。因此,开展极端工况下摩擦衬垫与钢丝绳的高速摩擦学性能研究,进而对现有衬垫材料进行改性,力图提高其在恶劣环境下的摩擦因数和耐磨性,对确保矿井安全生产,提高经济与社会效益等方面都具有重大意义。本文在高等学校博士学科点专项科研基金项目——“极端环境下提升钢丝绳与衬垫高速摩擦学性能研究”(编号:20060290505)的资助下,针对矿井摩擦提升机经常发生恶性滑绳事故的问题,采取试验研究与理论分析相结合的方法,在实验室模拟矿井实际环境工况开展提升钢丝绳与摩擦衬垫滑动试验研究,掌握衬垫摩擦磨损特性变化规律,进而研制高性能摩擦衬垫,提高其在恶劣工况下的摩擦学性能。首先,模拟矿井提升机极端环境下的恶劣工况,在自制试验台上开展衬垫材料在高速、重载、油润滑条件下的摩擦学试验,利用扫描电镜及X射线能谱仪分析衬垫材料的磨损形貌与化学结构,进而分析衬垫在极端工况下的磨损机理与失效形式。其次,考虑不同晶须的特性差异,分别选择若干种无机晶须为填料,制备无机晶须改性衬垫材料,通过力学、热分析及摩擦学试验,考察晶须对衬垫材料力学性能、耐热性能及摩擦磨损特性的影响规律;利用扫描电镜,分析不同衬垫材料的磨损机制,探求不同晶须对衬垫材料的作用规律,从而确定改性效果最优的晶须种类。再次,结合拟水平与均匀设计试验方法,以树脂基体、无机晶须及芳纶浆粕的含量为影响因子,对衬垫材料进行配方设计;基于支持向量机理论,建立不同配方改性材料的摩擦学参数预测模型,考察不同组分及其含量对材料摩擦学行为的影响规律;基于多属性决策理论,以典型工况下的摩擦学特性为准则,对无机晶须与芳纶浆粕混杂改性衬垫材料进行配方优选。最后,针对改性衬垫材料,以比压和滑动速度为因子,采用中心复合试验设计法开展正常提升及恶劣工况下的模拟试验;基于响应曲面模型理论,探求材料摩擦磨损特性受比压和滑动速度等单因素及多因素交互作用的影响规律,分析材料摩擦因数及磨损率对各因素变化水平的敏感程度;结合对材料微观形貌及表层成分变化的分析,考察在不同条件下材料的磨损机理变化;在摩擦学试验的基础上,利用人工神经网络理论,建立全工况范围的衬垫摩擦因数预测模型。更多还原

【Abstract】 Friction lining is a key component of the friction hoist, and its performance is directly related to the hoisting capacity, efficiency and safety. In recent years, the studies of wire rope and friction lining were carried out mainly under low velocity, and the tribological properties of friction lining under severe conditions such as heavy load and high velocity have not been totally understood. When the non-normal slide caused by overloading and other unexpected factors occurs, a great deal of friction heat accumulates on the surface of friction lining, which results in drastic changes in temperature filed. Accordingly, the friction coefficient and wear resistance exhibit sharp decline which finally leads to serious accidents. Therefore, to carry out the investigation on tribological behaviors of friction lining and wire rope under severe conditions and consequently modify the material of friction lining, in order to improve its friction coefficient and wear resistance, is helpful to ensure safe hoisting and enhance economic and social benefits.This dissertation was financially supported by Research Fund for the Doctoral Program of Higher Education of China. Aiming at the frequent occurrence of serious slipping accidents in coal mine, the methodology of theoretical and experimental analysis was employed, and the investigation of tribological properties between wire rope and friction lining was carried out in the laboratory simulating the real working conditions of coal mine. The goal is to master the tribological behaviors of friction lining, then to develop new material of friction lining which exhibits better properties under severe condition.Firstly, the sliding experiment between friction lining and wire rope was carried out on the tester under the condition of high velocity, heavy load and grease lubrication, which simulated the severe working condition of coal mine. Then, the SEM and XPS were employed to analysis the morphology and chemical structure of worn surfaces, and the wear mechanism and failure reasons were obtained consequently.Secondly, taking the character differences into consideration, several types of whiskers were chosen as reinforcements to prepare the whisker modified material. Afterwards, the effect of whisker on the physical and tribological properties was studied with experiments, and the morphology of worn surfaces was investigated with SEM. According to the different action laws of whisker, certain type of whisker which showed the best modification effect was fixed.Thirdly, the material formulations, in which the weights of PF, CaSO4 whisker and aramid fibre were considered as factors, were designed with quasi-level uniform method. Based on the support vector theory, the prediction model of tribological properties for different formulations was established to study the effect of ingredients and their weights on the tribological properties. Considering the tribological parameters under different conditions as criteria, the optimal formulation was chosen based on the method of AHP and PROMETHEE.Finally, the friction experiments of the newly developed material were conducted with the method of central composite design. The RSM was employed to analyze the sensitivity of friction coefficient and wear rate affected by the independent and interactive effect of velocity and pressure. Furthermore, the wear mechanism of developed material under different conditions was studied on the basis of the morphology and chemical structure of worn surfaces. In the end, with the experimental data, the friction coefficient prediction model was established based on the artificial neural network covering the whole range of velocity.更多还原