树脂基摩擦材料的设计及其制动性能研究

发布时间：2018-01-07 03:35

本文关键词：树脂基摩擦材料的设计及其制动性能研究　出处：《太原理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：制动摩擦材料作为制动器的关键性部件,其性能的好坏直接关系着制动系统运行的安全性和稳定性。然而,现有的矿山机械制动系统的制动摩擦材料,都不同程度存在摩擦因数低、制动性能差、使用寿命短等不足,难以满足矿山机械制动中特有的制动力矩大、制动次数频繁、工矿条件恶劣等要求。本课题针对上述现实问题,通过理论和试验研究,以自行制备的树脂基制动材料为研究对象,探讨树脂基体、混杂纤维、工况条件对摩擦材料制动性能的影响及其摩擦磨损机理,以期为高摩擦长寿命树脂基摩擦材料的研究和应用提供理论和试验依据。采用热压烧结技术分别研制了以酚醛树脂(PF)、腰果壳油改性酚醛树脂(CNSLPF)、环氧改性酚醛树脂(EMPF)为基体的摩擦材料,并在不同制动速度、制动压力下研究其制动性能,研究结果表明:CNSLPF试样具有较为稳定的摩擦系数和最小的磨损率,并且对偶制动轮磨损较小;磨损表面平整光滑,磨损形式为微犁沟和疲劳剥落。制备的四种不同CNSLPF含量的树脂基摩擦材料的硬度随树脂含量的增加明显增大,摩擦因数与摩擦表面温度随时间均为先增加后趋于稳定,较高的表面温度有利于减小摩擦系数的波动;树脂含量在26%~28%时,摩擦磨损综合性能最佳。采用体积分数28%的CNSLPF作为粘结剂,采用陶瓷纤维、碳纤维、矿物纤维、芳纶纤维作为增强组元,采用L_9(3~4)正交试验表进行正交优化设计,通过信噪比分析、方差分析,确定出因子的主次影响以及纤维配比,研究表明:芳纶纤维对摩擦因数与磨损率的影响显著,能最大程度的增大摩擦因数、减小磨损;陶瓷纤维和矿物纤维由于纤维本身较脆,不利于摩擦材料磨损量的提高;碳纤维本身的润滑性与高导热性对摩擦表面层有重要影响,对磨损量影响显著。最后,在干、湿两种制动工况下,研究了摩擦因数、磨损率随不同制动压力、制动速度的变化规律,并对磨损机理进行了相关探讨。干摩擦条件下,摩擦因数波动范围为0.36~0.5;水制动条件下,摩擦因数波动范围为0.2~0.4。干、湿两种制动工况下,摩擦因数均随滑动速度增加先增大后减小,摩擦因数的最大值随着制动载荷的增加向坐标原点移动。低载荷制动条件下,摩擦因数变化曲线只有上升部分;高载荷制动条件下,摩擦因数变化曲线只有下降部分。干摩擦条件下,摩擦接触面磨屑分布较多、质量较差,磨损机理为三体磨损,并伴随有第二接触面的生成、消退,摩擦性能不稳定,磨损较大;潮湿工况下,摩擦面光滑平整、表面质量更好,磨损机理为裂纹与犁沟,水分的润滑、冷却、渗透起到了降低摩擦因数、减小磨损的作用。
[Abstract]:Brake friction materials as the key components of the brake, its performance will directly affect the brake system's safety and stability. However, the brake friction material of the existing mine mechanical brake system, there are different degrees of low friction factor, poor braking performance, short service life, difficult to meet the specific braking torque of mining machinery the brake, brake in frequent mining conditions. Aiming at the above problems, through theoretical and experimental research, research on resin matrix brake material self prepared to investigate resin matrix, hybrid fiber, working conditions affect the braking performance of friction materials and friction and wear mechanism, to provide theoretical and experimental basis for the research and Application of high friction and long service life of resin based friction materials were developed. Based on phenolic resin by hot pressing sintering technology (PF), Cashew oil modified phenolic resin (CNSLPF), modified epoxy resin (EMPF) as the matrix of friction material, and at different braking speeds, the braking performance of the brake pressure, the results show that the CNSLPF sample has stable friction coefficient and minimum wear rate, and dual wheel brake wear small. Wear; smooth surface, wear form of micro furrow and fatigue spalling. The preparation of four kinds of different content of CNSLPF resin based friction material hardness with increasing resin content increased, friction coefficient and friction surface temperature increase at first and then tends to be stable, higher surface temperature is beneficial to reduce the friction coefficient fluctuation; resin content in 26%~28%, the friction and wear the best performance. The 28% volume fraction of CNSLPF as binder, ceramic fiber, carbon fiber, mineral fiber, aramid fiber as the reinforcing group Yuan, using L_9 (3~4) orthogonal optimized design of orthogonal experiment, the signal-to-noise ratio analysis, variance analysis, determine the primary and secondary factors and fiber ratio, research shows that the aramid fiber had significant effects on the friction coefficient and wear rate, to the maximum extent increase the coefficient of friction, reducing wear of ceramic fiber; because the fiber and mineral fiber itself more brittle, is not conducive to the quantity of materials to improve the friction and wear; lubrication and high thermal conductivity of carbon fibers have an important effect on the friction surface layer significantly affect the amount of wear. Finally, in the dry, wet two kinds of braking condition, friction coefficient, wear rate with different pressure brake, brake speed variation, and the wear mechanism were discussed. The dry friction condition, the friction coefficient fluctuation range is 0.36~0.5; the water brake condition, the friction coefficient fluctuation range was 0.2 ~0.4. dry, wet two kinds of braking Next, the friction coefficient increased with increasing the sliding velocity increases first and then decreases, the friction coefficient increased with the maximum braking load moves to the origin of coordinates. The low load under braking curve, the change of friction coefficient only increased; high load under braking, the friction coefficient curve changes only decreased. Under the dry friction condition of chip distribution more, the friction contact surface of poor quality, the wear mechanism for three body wear, and accompanied by the second generation of contact surface, friction dissipated, unstable performance, wear large; damp condition, friction surface smooth, better surface quality, wear mechanism for cracks and furrows, water lubrication, cooling, permeability to reduce the friction coefficient, wear reducing effect.

【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD404

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