Tribological Behavior And Modification Of Friction Lining For Mine Hoist

As the main machine in elevating and down-passing materials,transporting workers and equipment,the friction hoist depends on the friction between wire rope and friction lining to achieve the normal operation.The performance of the friction lining is directly related to the hoisting property,safety and reliability.In recent years,the non-normal slide between wire rope and friction of many malignant accidents caused by overloading leads.And the ultimate reason is friction coefficient and wear resistance weakened in the process of working.Therefore,the study of contact form and tribological behavior between wire rope and friction lining and modify the material of friction lining,in order to improve its friction coefficient and wear resistance,is important to ensure produce safety in coal production.Firstly,combining the special helical structure of wire rope,the contact characteristics and the stress of the wire rope and friction lining in working process was analyzed.The contact model between wire rope and friction lining was set up and simulated by the finite element software,and the change law of stress under one,two or three strands and wire rope was studied.The results show that the wire rope and the friction lining are not completely contacted,and the contact area is divided into three parts.In the process of sliding,the wire rope and the lining are kept with discontinuous contact at two or three points.Secondly,combining the working conditions of lining,the experiment scheme was designed and the experiment was completed under the friction and wear tester.Then,the change law of load and speed was studied,and the SEM was used to analysis the wear mechanism of the worn surfaces under the highest sliding speed and the highest load conditions.The results show that the friction coefficient and wear rate of the lining increases with the load increases,decreases with the sliding speed increases.And adhesive wear was the main wear mechanism under dry friction and the abrasive wear,fatigue wear were the wear mechanism under water friction.Then,the performance of materials was researched and the modified lining formulations which the weights of phenolic resin modified by NBR,Kevlar and glass fibre were considered as factors were designed with quasi-level uniform method.The better modified material which prepared by hot-pressing was chosen by tribological experiments,and the tribological properties and wear mechanism of worn surfaces were analyzed.The experiment results show that the materials properties will decline because of the too less resin content,and high wear volume because of the glass fiber excessive,the wear resistance of the material can improve because of adding aramid fiber;the friction coefficient and wear rate of modified material increases with load increases,and decrease with the increase of sliding velocity under dry friction and water friction.The wear mechanism of modified material was fatigue wear and the wear mechanism of ball was abrasive wear.Finally,the filler was studied based on the fiber reinforced modified formulation.The nano-SiC,nano-Al₂O₃,nano-TiO₂,nano-SiO₂ was used as filler to prepare the modified materials,and the tribological properties and wear mechanism of different filler modified materials were analyzed.The research shows that because of the small size and high surface energy of nanoparticles and it’s lubricant function,added nanoparticles can effectively improve the binding strength between matrix and fiber,and improve wear properties of materials,showed lower wear rate.The wear mechanism of lining modified by nanoparticles was fatigue wear and abrasive wear and the wear mechanism of dual parts mainly for abrasive wear.