摘要
针对铜基换挡摩擦片在极限工况下易发生强烈黏着磨损,继而导致烧蚀与磨损失效的问题,研制了铝青铜-Ti_(3)AlC_(2)复合材料及其工程样件.测试了样件在不同工况下的摩擦系数、磨损率、闭锁冲击系数、传递扭矩、耐振动冲击次数及耐热冲击系数,并分析了力学性能、磨损表面状态及摩擦磨损机理.结果表明:Ti_(3)AlC_(2)能够提高铝青铜基体的硬度和抗压强度,并减弱黏着磨损,从而提高复合材料的耐磨性能和耐热冲击性能;Ti3AlC2可使换挡摩擦片具备稳定的传递扭矩,并降低其在重载荷与高转速下的摩擦冲击;过量的Ti_(3)AlC_(2)会降低复合材料的组织均匀性和结合力,并对耐磨性能和耐振动冲击性能造成不利影响;通过优化Ti_(3)AlC_(2)含量可使复合材料兼顾良好的力学性能、摩擦学性能及耐冲击性能,进而提升换挡摩擦片在极限工况下对摩擦冲击、热冲击及振动冲击的承载能力.
On account of the increasing power density and maneuvering characteristics of heavy vehicle,the speed change mechanism faces harsher working conditions.For example,on some vehicles the relative rotate speed of friction plate rise 32%,the pressure of friction plate rise 30%,and the time of sliding friction rise 60%.Under these conditions,friction plates require to possess excellent shock resistance,which avoid the ablation,severe wear and peel off of material.Meanwhile,it is important to adjust and control friction coefficient based on the inertia and shifting parameter of speed change mechanism.If the friction coefficient is too low,friction plate will skid during shifting.It resulted in the irregular change of vehicle speed and deficiency of power.However,if the friction coefficient is too high,the shifting shock will rise during shifting.It causes severe wear and decrease of service life.Therefore,in order to satisfy the needs of high maneuverability,the friction plate must have good tribological performance and shock resistance simultaneously.The using copper-based friction plate occurs violent adhesive wear,thermal failure and wears failure under utmost conditions because of the weak wear resistance and shock resistance.Hence,it is necessary to study new friction plate materials possessing good tribological performance,shock resistance and reliability.At present,the friction layer materials of friction plate mainly include powder metallurgy material,paper-based material,resinous material and ceramic material.The paper-based material and resinous material friction plates crack and fall off easily under high pressure,so they cannot be used on heavy vehicle.The ceramic material friction plate shows poor vibratory shock resistance,which resulted in the large thickness of friction plates.So it is difficult for ceramic material friction plate to install in transmission case.The friction coefficient of ceramic material decreases in water or oil environment,which leads to the reduction of friction plate transfer torque.Therefore,it is more feasible to design the material prescription,preparation technology and structure of powder metallurgy material friction plate.In addition,the aluminium bronzes have good mechanism properties,corrosion resistance and tribological performance.Thus,aluminium bronzes can be used as matrix material to prepare self-lubricating composites.In terms of this issue,the bronze-Ti_(3)AlC_(2) composites and engineering samples were prepared.The friction coefficient,wear rate,impacting coefficient,transfer torque,vibratory shock resistance and thermal shock resistance were tested under different conditions.The mechanical properties,worn surfaces state and friction mechanism were analyzed.Results showed that,Ti_(3)AlC_(2) improved the compressive strength and hardness of composites.Ti_(3)AlC_(2) increased the wear resistance and thermal shock resistance limitation by weakening the adhesive wear.The friction plates containing Ti_(3)AiC_(2) possessed stable transfer torque,and the shock during friction process under heavy load and high speed conditions was weakened by increasing lubricating property.However,the excess Ti_(3)AlC_(2) was harmful to wear resistance and vibratory shock resistance by reducing homogeneity of structure and binding force.After optimizing the content of Ti_(3)AIC_(2),the bronze-Ti_(3)AIC_(2) composites possessed good mechanical properties,tribological performances and shock resistance,which improved the wear resistance,vibratory shock resistance and thermal shock resistance of friction plates under utmost conditions.
作者
金孔杰
胡铮
谈辉
王帅
韩明
田金山
乔竹辉
杨军
JIN Kongjie;HU Zheng;TAN Hui;WANG Shuai;HAN Ming;TIAN Jinshan;QIAO Zhuhui;YANG Jun(China North Vehicle Research Institute,Beijing 100072,China;State Key Laboratory of Solid Lubrication,Lanzhou Institute of Chemical Physics,Chinese Academy of Sciences,Gansu Lanzhou 730000,China;Nation United Engineering Laboratory for Advanced Bearing Tribology,Henan University of Science and Technology,Henan Luoyang 471023,China)
关键词
铝青铜
钛铝碳复合材料
摩擦学性能
耐冲击性能
工程应用
bronze
titanium-aluminum-carbon composite
tribological property
shock resistance
engineering application
作者简介
通信作者:金孔杰,E-mail:jinkongj@163.com,Tel:+86-18800168832.
