【作者】 张超；

【导师】 刘启跃；

【作者基本信息】 西南交通大学 ， 机械工程（专业学位）， 2021， 硕士

【摘要】 制动盘与闸片作为保障高速列车运行安全的基础组成部分,其摩擦制动行为对列车安全运行具有关键影响。随着哈大高铁的开通运营,我国高速列车正式打开高寒高速铁路发展的大门。低温环境给列车带来制动摩擦性能不稳定、磨耗异常等严重问题,对列车的制动安全带来极大隐患。因此,低温环境下盘形制动界面摩擦行为研究对于保障高速制动系统的可靠服役具有重要意义。论文首先利用销-盘磨损试验机研究了环境温度和摩擦条件对制动盘/闸片材料磨损性能的影响,揭示了制动盘/闸片材料在不同环境温度和摩擦条件下的磨损与损伤演变规律;然后通过MM-1000高速摩擦磨损试验机对高速列车盘式制动材料进行了低温环境下制动模拟试验,研究了初始制动速度、制动压力、环境温度等试验参数对摩擦制动性能的影响。论文研究的主要结论如下:(1)在-30～20℃范围内,连续接触试验中,随环境温度的升高,磨损率呈现先增加,后降低的变化趋势;闸片试样表面脱落、颗粒破碎减少,第三体面积增大;盘试样表面点蚀现象先加重后逐步得到缓解。间歇接触试验中,在0℃和-10℃环境温度下,平均摩擦系数和磨损率较大,试样表面脱落坑、划痕和犁沟增加。(2)在0.5～1.5MPa范围内,随接触压力增加,趋于稳定后的摩擦系数波动降低,试样磨损率增加,闸片试样表面第三体面积减小,脱落坑数量和面积增加;-20℃环境温度下,盘试样表面损伤除犁沟、黏着颗粒和第三体外,点蚀损伤随接触压力加重;20℃环境温度下,盘试样表面块状脱落和犁沟现象增加。(3)在0.3～0.7m/s范围内,随滑动速度增加,摩擦系数波动降低,试样磨损率减小,且盘试样磨损率增长速率大于闸片试样。闸片试样表面第三体面积增大,脱落坑面积减小;盘试样表面犁沟和黏着颗粒减少,第三体面积增加。(4)制动过程中,在-30～20℃范围内,随环境温度的降低,制动距离和闸片试样磨损率呈现先增加后减小的变化趋势;闸片试样表面脱落和破碎增加,第三体面积减小。20℃环境温度试样表面温升和闸片试样磨损率低于-30～0℃环境温度。(5)在-20℃环境温度,80～110km/h初始制动速度范围内,随初始制动速度增加,平均摩擦系数增大;闸片试样表面石墨颗粒显著减少,第三体面积增加。0.8～1.2MPa制动压力范围内,随制动压力的增大,平均摩擦系数减小;闸片试样表面石墨颗粒、脱落和破碎增多。更多还原

【Abstract】 The brake disc and pad are basic components for ensuring the operation safety of high-speed train.The friction braking behaviors between the brake disc and pad has important significance for train safety operation.With the operation of Harbin-Dalian high-speed railway,China’s high-speed trains have officially started the period to the development of Alpine high-speed railway.Low temperature environment brings serious problems such as unstable braking friction performance,abnormal wear,etc.which brings great hidden danger to the braking safety of trains.Therefore,the study of the friction behavior of disc brake interface in low temperature has great significance to ensure the reliability of high-speed braking systems.Firstly,the effects of ambient temperature and contact conditions on the wear properties of brake disc/pad materials were studied using a pin-on-disc testing rig,and the evolution of wear and damage of brake disc/pad materials under different ambient temperatures and contact conditions was revealed.Then,a MM-1000 high-speed friction braking machine was used to simulate the braking performance of disc brake materials of high-speed train in low temperature environment.The effects of initial braking speed,braking pressure and ambient temperature on friction and braking performance were studied.The main conclusions are as follows:(1)In the range of-30～20℃,during the continuous contact test,with the increased of ambient temperature,the wear rate first increased and then decreased.The fall off and particle breakage decreased on the brake pad sample surface,and the area of the third body increased.The fatigue pitting on the surface of the disc sample first increased and then gradually lighted.In the intermittent contact test,the average friction coefficient and wear rate were relatively high at 0℃ and-10℃,and the pits,scratches and furrows on the sample surface increased.(2)In the range of 0.5～1.5MPa,with the increased of contact pressure,the fluctuation of friction coefficient decreased,the wear rate increased,the area of the third body decreased,and the number and area of the falling pits increased.At an ambient temperature of-20℃,the surface damage of the disc sample except for furrows,adhesive particles and the third body,and the fatigue pitting damage increased with contact pressure.At a normal temperature of 20℃,the massive shedding and furrow phenomenon on the surface of the disc specimen increased.(3)In the range of 0.3～0.7m/s,with the increased of sliding speed,the fluctuation of friction coefficient and the wear rate decreased,and the growth rate of wear rate of disc specimen was greater than that of brake pad specimen.The area of the third body formed of the brake pad sample increased,and the area of the shedding pit decreased.The surface furrow and adhesive particles on the surface of the disc sample decreased,the area of the third body increased.(4)In the braking process,within the-30～20 ℃,with the decreased of the ambient temperature,the braking distance and the wear rate of the brake pad sample increased and then decreased.The surface peeling and breakage of the brake pad samples increased,and the area of third body decreased.The surface temperature rise of the sample and the wear rate of the brake pad sample at an ambient temperature of 20℃ were lower than at-30～0℃.(5)Under the ambient temperature of-20℃,at the initial braking speed range of80～110km/h,the average friction coefficient increased with the increased of initial braking speed.The graphite particles on the surface of brake pad sample decreased significantly,and the area of third body increased.Under the braking pressure range of 0.8～1.2MPa,with the increased of the braking pressure,the average friction coefficient decreased;the graphite particles on the surface of the brake pad samples,shedding and breakage increased.更多还原