摩擦衬垫的动态接触与微观摩擦机理研究

发布时间：2018-06-14 06:16

本文选题：摩擦衬垫 + 原位观测　；参考：《中国矿业大学》2017年硕士论文

【摘要】：摩擦衬垫作为摩擦式提升机的关键部件,提升机主要依靠摩擦轮上的摩擦衬垫来承受钢丝绳及绳端载荷,并依靠其与钢丝绳之间的摩擦力进行传动,其摩擦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。本文基于白箱理论,模拟摩擦衬垫的工作状态,利用VW9000高速摄像摄像仪原位观测K25摩擦衬垫在不同载荷、速度下的摩擦过程,获得实时的微观的界面接触形貌,揭示各种微观现象的发生、发展的动态过程,以及多因数下衬垫材料的摩擦机理,进而为研究摩擦衬垫与钢丝绳间的摩擦机理提供基础依据。以目前国内摩擦式提升机广泛采用的K25、GM-3和G30摩擦衬垫为研究对象,开展衬垫材料在不同动态加载力下摩擦实验的实时观测,获得摩擦界面的接触状态与微观磨损形貌,结合衬垫磨屑的成分变化,揭示衬垫的磨损机理。建立衬垫的粘弹性与其摩擦系数之间的关联关系,分析在动态载荷条件下摩擦衬垫与钢丝绳实际接触滑移的摩擦系数特征。最终获得了以下主要结论:(1)K25摩擦衬垫的定载滑移实验表明,粘着摩擦与滞后摩擦导致摩擦系数随时间呈现指数增长现象。随着滑移速度的增加,摩擦系数呈现上升的趋势。在高速、高载的条件下衬垫表面的摩擦机理主要为粘着摩擦;在低载、低速条件下衬垫表面的摩擦机理主要为滞后摩擦;从高载、高速工况向低载、低速工况过渡中衬垫表面的摩擦机理为粘着与滞后摩擦的混合摩擦机理。(2)加载和卸载阶段内,K25摩擦衬垫界面存在明显的粘着、半粘着和滑移三种接触状态;GM-3与G30摩擦衬垫摩擦界面只存在明显的粘着和滑移两种接触状态。此外,K25摩擦衬垫的加载与卸载过程中粘着阶段的摩擦机理主要为粘着摩擦,同时半粘着与加载滑移阶段内衬垫的摩擦机理主要为粘着摩擦和滞后摩擦的混合摩擦机制,而卸载滑移阶段内衬垫的摩擦机理主要为粘着摩擦。GM-3摩擦衬垫与G30摩擦衬垫的瞬时摩擦机理相同,粘着阶段的摩擦机理主要为粘着摩擦,加载滑移阶段内衬垫的摩擦机理主要为粘着摩擦和滞后摩擦的混合摩擦机制,而卸载滑移阶段内衬垫的摩擦机理主要为粘着摩擦。(3)K25、GM-3及G30衬垫与钢丝绳的摩擦面均分布着条状的具有较高方向性的凸峰和凹谷。K25摩擦衬垫凹谷内基体材料发生严重的塑型变形,同时凹谷边缘分布着犁沟划痕,凸峰位置分布着大量团聚的磨屑。GM-3摩擦衬垫凹谷内基体材料同样发生严重的塑型变形,同时表面产生大量的贝壳状的剥落坑,但只有极少数的磨屑粒子产生。G30摩擦衬垫凹谷内基体材料的塑型变形最严重,表面已出现黑化,但磨损面无明显的剥落坑与团聚磨屑产生。(4)随着动态载荷的增加,K25摩擦衬垫接触界面产生的磨屑逐渐增加,形成致密第三体,造成摩擦系数减小。此外,微观磨屑形貌表明动态载荷下衬垫表面磨损主要为粘着磨损。随着动态拉伸力提升至2-13KN,不断地在接触表面聚集的摩擦热,促使摩擦衬垫表面材料发生软化、改性,导致摩擦衬垫表面磨屑分子内氢键发生氧化断裂,形成游离羟基,引起磨屑表面部分黑化,磨屑数量明显增加,产生明显的热粘着磨损。(5)随着动态拉伸力幅值的增加,粘着摩擦导致了K25摩擦衬垫滑移阶段内摩擦系数的减小,而动态拉伸力由3-5KN增加到3-8KN过程内滞后摩擦主导GM-3与G30摩擦衬垫滑移摩擦系数的增加,动态拉伸力由3-8KN增加到3-10KN过程内粘着摩擦主导GM-3与G30摩擦衬垫滑移摩擦系数的减小。随着加载速度的增加,滞后摩擦导致了K25摩擦衬垫滑移摩擦系数的下降,而粘着摩擦导致了GM-3摩擦衬垫滑移摩擦系数的增大,粘着与滞后摩擦导致了G30摩擦衬垫呈现先增加后减小的趋势。
[Abstract]:As the key component of the friction hoist, the friction liner relies mainly on the friction pad on the friction wheel to bear the load of the wire rope and the rope end, and depends on the friction between the steel wire and the wire rope. The friction performance of the hoist is directly related to the working energy of the hoist, the lifting efficiency and the safety and reliability. Box theory, simulating the working state of friction lining, using VW9000 high-speed camera camera in situ to observe the friction process of K25 friction pad under different load and speed, obtain real time micro interface contact morphology, reveal the occurrence of various microcosmic phenomena, the dynamic process of development, and the friction mechanism of the liner material under multi cause, and then The basic basis for the study of friction mechanism between friction gaskets and wire rope is provided. K25, GM-3 and G30 friction gaskets widely used in domestic friction hoists are used as the research objects. The real time observation of the friction experiment of the lining material under different dynamic loading forces is carried out, the contact state and the micro wear morphology of the friction interface are obtained, and the liner is combined with the liner. The wear mechanism of the debris is revealed. The relationship between the viscoelasticity and the friction coefficient of the liner is established, and the frictional coefficient characteristics of the actual contact slip between the friction lining and the wire rope under the dynamic load are analyzed. The following main conclusions are obtained: (1) the constant load slip experiment of the K25 friction pad shows that the adhesive friction is worn. Friction coefficient increases exponentially with time. With the increase of slip velocity, the friction coefficient presents an upward trend. Under high speed and high load, the friction mechanism of the surface of the liner is mainly adhesive friction; the friction mechanism of the surface of the liner is mainly lagging friction under low load and low speed; from high load to high speed, the friction mechanism of the lining surface is mainly lagging friction. The friction mechanism of the liner surface in the transition of low speed conditions is a mixed friction mechanism of adhesion and lag friction. (2) there are obvious adhesion, semi adhesive and sliding contact state in the interface of K25 friction pad during loading and unloading stage, and there are only two kinds of contact and slip contact between GM-3 and G30 friction pad. In addition, the friction mechanism of the adhesion stage in the loading and unloading process of the K25 friction pad is mainly adhesive friction, while the friction mechanism of the liner in the stage of semi adhesive and loading slip is mainly the mixed friction mechanism of adhesive friction and lag friction, while the friction mechanism of the liner in the unloading and slip stage is mainly the adhesive friction.GM-3 friction. The instantaneous friction mechanism of the friction lining and the G30 friction pad is the same. The friction mechanism of the adhesion stage is mainly adhesive friction. The friction mechanism of the liner in the stage of loading slip is mainly the mixed friction mechanism of adhesive friction and lagging friction, while the friction mechanism of the lining in the unloading and slip stage is mainly adhesive friction. (3) K25, GM-3 and G30 liner and its liner. The friction surfaces of the wire ropes are distributed in a strip of high directional and concave Valley.K25 friction pads with a serious plastic deformation, while the edge of the concave Valley is distributed in the furrow scratches. The position of the convex peak is distributed in a large number of debris.GM-3 friction pads in the concave valley. At the same time, a large number of shell shaped pits are produced on the surface, but only a few debris particles produce the most serious plastic deformation of the matrix material in the concave valley of the.G30 friction pad. The surface has appeared blackening, but there is no obvious peeling pit and agglomeration debris in the wear surface. (4) with the increase of dynamic load, the contact interface of the K25 friction pad is produced. In addition, the microchip morphology indicates that the surface wear of the liner is mainly adhesive wear. With the dynamic tensile force rising to 2-13KN, the frictional heat of the contact surface is constantly improved and the friction lining surface materials are softened and modified, resulting in friction pads. The internal hydrogen bonds in the surface of the surface debris are oxidized and fractured, forming free hydroxyl groups, causing partial blackening of the debris surface and increasing the number of debris. (5) with the increase of the amplitude of the dynamic tensile force, the adhesion friction leads to the decrease of the friction coefficient within the sliding stage of the K25 friction pad, and the dynamic tensile force increases from 3-5KN. In the process of 3-8KN, the sliding friction coefficient of the friction dominant GM-3 and the G30 friction pad is increased, and the sliding friction coefficient of the adhesive friction dominant GM-3 and the G30 friction liner is reduced by the increase of the dynamic tensile force from 3-8KN to the 3-10KN. With the increase of the loading speed, the lag friction leads to the decrease of the sliding friction coefficient of the K25 friction pad. Friction resulted in the increase of the sliding friction coefficient of GM-3 friction pad, and the friction and wear of G30 friction pad increased first and then decreased.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD534.3

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