基于台架试验的长下坡路段满载中型货车制动风险阈值研究

Study on Braking Risk Threshold Value for Full-loaded Medium Trucks on Continuous Long and Steep Downhill Sections Based on Bench Test

货车在长下坡过程中为保证行驶安全需要连续制动,容易导致制动器温度不断上升而出现热衰退现象,严重时会导致制动失效和车辆失控,进而发生恶性交通事故。通过台架模拟试验测试了长下坡路段满载中型货车制动鼓温度的变化过程,建立了组合预测模型,分析了不同制动初始速度下鼓式制动器温度的变化规律,得出不同制动初始速度对应的制动器失效温度风险阈值和最大临界制动次数。结果表明:制动初速度越大,制动频次越高,制动器就越容易达到失效状态;当制动鼓发生"热衰退"现象后,其制动效能下降速率也会随着初速度的增大而增大;同时在预测制动风险时,对单一预测模型进行适当组合,可以提高预测精度、减小预测误差。

Continuous braking is needed to ensure driving safety during the trucks traveling on long downhills, which is easy to cause the rising of brake temperature and then to occur the heat fade of trucks＇ brakes. When the problem gets more serious, it will lead to brake failure and the vehicles out of control, and then the occurrence of vicious traffic accidents. The brake drum temperature variation process of full-loaded medium truck on long downhills is simulated through bench simulation test, the combination forecast model is established, the regularity of drum brake temperature variation at different initial brake speeds is analyzed, and the temperature risk threshold values and the maximum critical braking time of brake failure corresponding to different initial braking speeds are obtained. The result shows that （ 1 ） the higher the initial braking speed and the higher the braking frequency, the easier it is for the brake system to reach the failure state ; （2） after the brake drum ＂heat fade＂ occurs, the declining rate of braking efficiency will increase with the increase of the initial speed; （3） at the same time, appropriate combination of several single prediction models can improve the prediction accuracy and reduce the prediction error when predicting the braking risk.