全寿命周期内合成闸瓦的摩擦磨损性能研究

Study on Friction and Wear Performance of Synthetic Brake Shoe During the Whole Life Cycle

利用1:1制动动力试验台,按照紧急制动和常用制动的测试程序,对全新的和即将磨耗到限的高摩擦系数合成闸瓦进行全寿命周期内摩擦磨损性能测试。新闸瓦经过5个完整的常用制动和紧急制动测试循环后有以下表现:在每个循环内,相同制动压力下,摩擦系数随制动初速度的提高而降低;相同初速度下,常用制动的摩擦系数比紧急制动高,车轮踏面温升比紧急制动低;同样制动条件下,常用制动平均摩擦系数的变异系数在1.28%~5.17%范围内,车轮踏面温升的变异系数在4.85%~6.67%范围内;紧急制动平均摩擦系数的变异系数在2.36%~5.04%范围内,车轮踏面温升的变异系数在2.31%~5.51%范围内;每个测试循环的能量磨耗量没有显著变化,在0.24~0.26 cm3/MJ之间。即将磨耗到限的闸瓦,其摩擦系数及磨耗量数值在新闸瓦5组测试结果的波动范围之内。研究结果表明:在全寿命周期内,合成闸瓦摩擦磨损性能没有显著变化。研究结论为合成闸瓦的失效分析提供了依据。

The friction and wear performance of a new and a close-to-worn-to-the-limit composite brake shoes with high friction coefficient in the whole life cycle were tested by using full-scale dynamometer brake test bench according to the test procedures of common braking and emergency braking.After 5 complete test cycles of common braking and emergency braking of the new brake shoe,it was found that in each cycle,the friction coefficient decreased with the increase of the initial braking speed under the same braking pressure.At the same initial speed,the friction coefficient of common braking was higher than that of emergency braking,and the temperature rise of wheel tread of common braking was lower than that of emergency braking.Under the same braking conditions,the variation coefficient of average friction coefficient of common braking was in the range of 1.28%~5.17%,and the variation coefficient of wheel tread temperature rise was in the range of 4.85%~6.67%.The average friction coefficient of emergency braking was in the range of 2.36%~5.04%,and the temperature rise of wheel tread was in the range of 2.31%~5.51%.The amount of wear calculated by energy per test cycle did not change significantly,ranging from 0.24 cm3/MJ to 0.26 cm3/MJ.The friction coefficient and wear value of the brake shoe which was close to worn to the limit were within the fluctuation range of the test results of the 5 groups of the new brake shoe.The results show that the friction and wear properties of the synthetic brake shoe have no significant change during the life cycle,and the conclusion provides a basis for the failure analysis of the synthetic brake shoe.