动态摩擦因数对蝶式制动器温度场影响的试验和模拟研究

Experimental and Simulation Research on the Influence of Dynamic Friction Coefficient to the Temperature Field of Disc Brake

针对蝶式制动器制动过程中温度场研究的需要,利用相似原理研制定速制动试验台,用以模拟摩托车匀速下长坡时的制动工况。制动试验台用车床的三爪卡盘控制固定在旋转轴上的制动盘做定速旋转运动,内外摩擦片通过液压力夹紧制动盘,使制动盘与摩擦片发生摩擦运动,通过热电偶、拉压力传感器、压力表、热成像仪分别测出定速制动50 s的摩擦片上固定点的温度变化、制动扭矩(经计算得出)的动态变化、制动力的均值、制动盘摩擦区域的温度场变化,实时显示并记录下来。定速制动摩擦试验机能实现不同转速、不同制动力等条件下,制动过程中的各变量的动态测量。试验还选取热成像仪测得的最大的温度为变量,研究摩擦因数随温度的变化。在试验的基础上,用ABAQUS对制动盘与摩擦片的相互作用做了一些仿真和分析。仿照实际模型1∶1建模,加载与边界条件与实际模型相同,将测得的摩擦因数随温度变化的数据输入接触条件,仿真得到制动盘与摩擦片温度场的变化。仿真与试验的结果对比表明摩擦因数动态变化的接触模型能很好的模拟制动的实际工况。

To research into temperature field of disc brake, as needed, a constant speed braking bench is developed to simulate the braking condition of motorcycle under long slope by similarity principle. The disc fixed on rotating shaft, which is clamped by three jaw chuck of lathe, rotate with constant speed. The disc is clamped by inner pad and outward pad though hydraulic pressure. Temperature evolution of certain point on outward pad, braking torque evolution, mean value of braking pressure, temperature evolution on the frictional area of disc are measured by thermal couple, pressure sensor, piezometer, thermal imager respectively. The braking bench could realize the dynamic test of all variables under different rational speed and different braking pressure. The maximum temperature is chosen as variable to research the evolution of friction coefficient with temperature increasing. Based on experiment, simulation and analysis are did by ABAQUS. Simulation models are made from actual model by the ratio 1：1, load and boundary conditions are the same as reality, the evolution of friction coefficient with increasing temperature is put into contact condition, finally, the evolutions of the temperature fields of disc and pad are obtained. Compare to the simulation result and experimental result, it shows that the contact model with dynamic friction coefficient is better fit into the actual braking condition.