根据汽车制动自调臂的工作原理和热力学特性,分析缺口盘与制动间隙之间的几何关系,建立缺口盘热变形模型;研究其均匀温度场下的热变形规律;定量分析缺口盘的热变形所产生的制动间隙自调增量。在多层高低温试验箱的基础上,设计自调臂高低温自调功能仿真测试装置,动态检测自调臂在阶梯温度下的制动间隙自调增量。对某型自调臂进行7组等温环境下的热变形试验,用于该热变形模型的正确性。试验结果表明,缺口盘热变形模型的相对误差均保持在[0.01,0.13]之间;缺口盘热变形模型与实测数据之间的灰关联度达到0.98,而传统的有限元法与实测值间的灰关联度为0.92:缺口盘热变形模型的平均绝对误差为0.140;有限元法计算的平均绝对误差为0.53°。上述试验结果表明,提出的热变形模型与传统的有限元法具有相同的热变形评估精度和准确性。由于该模型构建简单,与有限元法相比,本文的模型更适合于实际工程应用。
The thermal deformation model of cutaway disk is proposed for automatic brake adjuster based on its mechanical model. This model can solve the geometrical relationship between cutaway disk and the self-adjust clearance increment, illustrate the thermal deformation law, and calculate the self-adjust clearance increment caused by the thermal deformation of cutaway disk. A self-adjust performance test system of automatic brake adjuster with a multiple incubator is set up to dynamic test the clearance increment in varying temperatures. The experimental result with seven groups of trials shows that the relative error range is [0.01, 0.13]. Comparing with the true values, the grey incidence degree of our suggested model is 0.98 while that of FE model is 0.92. The mean absolute errors are 0.14° for our suggested model and 0.53° for FE model. It indicates that our suggested model is approximate to FE model both for accuracy and veracity. What's more, our suggested model is more suitable for measuring application because it is easy to build comparing twith FE model.