Research On The Inner Wall Temperature Inverse Of Truck Drum Brake And Its Application

In recent years,the requirements of trucks on the braking performance are getting higher with the truck toward the "high speed","heavy" trend of development.Drum brake performance index is discussed,and the effects on safety braking is analyzed from three aspects of the friction lining wear volume and friction torque,brake temperature rise by calculating the truck braking process of friction torque and the relationship between friction coefficient and the temperature of the brake friction lining from its structure and working principle.The rise of brake temperature has a significant impact on the truck braking performance.It is particularly necessary to the driver to master the work temperature of the truck brake when driving on the long downhill road.At present,there are some deficiencies such as the thermocouple is easy to be damaged,the distribution of the temperature of the brake cannot fully be reflected,highly cost because the traditional means of measuring the internal temperature of drum brake is that thermocouples is installed inside the braking device.Therefore,the method of identifying the inner wall temperature of drum brake is proposed based on the theory of the inverse heat transfer problem.This method avoids the shortcomings of traditional measure methods,and also it can comprehensively reflect the distribution of the brake drum temperature from the inversion results.This paper divides the whole solving process into two parts including direct heat conduction problem and inverse heat conduction problem according to the principle of solving inverse heat conduction problem.In order to solve the direct heat conduction problem,the EQ1141 G truck rear drum brake is been taken as the research object,and three-dimensional finite element simulation model of drum brake is established under certain assumptions by ABAQUS finite element simulation software.After inputting material parameters,the corresponding boundary conditions,this paper obtained the repeated drum brake transient temperature field by ABAQUS simulation according to the < Trucks and buses-Brake-Bench test methods GBT 12780-1999>.In order to solve the inverse problem,the inner wall temperature of drum brake inverse model was established based on the optimization theory.As the outer wall temperature of drum brake is considered as the basic data,the inner wall heat flux distribution of drum brake is inversed by the conjugate gradient method with the distribution of drum brake as the termination condition of the inversion model.At the same time,with the aid of MATLAB platform,the interface program of MATLAB and ABAQUS simulation software is established in order to build a complete drum brake temperature inverse procedure.There is the same trend between the inversion results and the true value of the distribution under certain conditions;this verifies the effectiveness of the temperature distribution of drum brake by the inverse heat conduction problem theory.At the same time,the effect of initial guesses,the measuring point position and the temperature measurement errors to the inversion results are discussed.Finally,the initial construction of drum brake temperature detection system is established based on the inversion algorithm and the inversion results.The structure and function modules of the system is also been analyzed.A new method of measuring the working temperature of drum brake is given by this system,and it will make the traffic safer on downhill road.