缩比摩擦副与1:1摩擦副温度和摩擦因数偏差的试验研究

Experimental study on braking temperature and friction coefficient deviation between reduced and 1:1 friction pair

缩比与1:1试验的结果是有偏差的,为认识影响偏差的各因素的作用,利用缩比试验台和1:1试验台,在制动压力0.19~0.49 MPa,制动速度50~220 km/h条件下,进行对比试验。结果表明:缩比制动盘的盘面峰值温度高于1:1制动盘,温差随制动压力的增加略有降低。平均摩擦因数的偏差与制动工况有关,制动压力0.19 MPa时,缩比摩擦副的平均摩擦因数大于1:1摩擦副的,差值在0.007~0.035之间;制动压力增加到0.49 MPa时,缩比摩擦副的平均摩擦因数小于1:1摩擦副的,差值在0.003~0.065之间。两种摩擦副的温度和摩擦性能存在偏差的原因在于冷却条件和摩擦弧长分布的不同,1:1试验制动盘的通风散热好、摩擦弧分散性大,使盘面温度均匀性好于缩比试验的。在高制动压力条件下,高温加剧了缩比条件下摩擦因数的衰减,导致低于1:1摩擦副的平均摩擦因数。

There is a deviation between the results of the reduced and the 1:1 test.To understand the effects of various factors,a reduced dynamometer and 1:1 dynamometer were used to conduct a comparative test under the braking pressure 0.19−0.49 MPa and the braking speed 50−220 km/h.The results show that the peak temperature of the reduced brake disc is higher than that of the 1:1 brake disc,and the temperature difference decreases slightly with the increase of the braking pressure.The deviation of the average friction coefficient is related to the braking conditions.The braking pressure is 0.19 MPa,the average friction coefficient of the reduced friction pair is greater than that of the 1:1 friction pair,and the difference is distributed between 0.007−0.035.When the braking pressure is increased to 0.49 MPa,the average friction coefficient of the reduced friction pair is lower than that of the 1:1 friction pair and the difference is distributed between 0.003−0.065.The reason for the deviation of the temperature and friction performance of the two friction pairs is the difference in cooling conditions and friction arc length distribution.The brake disc of the 1:1 test has good ventilation and heat dissipation,and the friction arc is highly dispersive,making the surface temperature uniformity better than that of the reduced test.Under high braking pressure conditions,the high temperature exacerbates the attenuation of the friction coefficient under reduced test,resulting in the average friction coefficient below the average friction coefficient of 1:1 friction pair.