| Full hydraulic braking system with its superior performance, are widely used in thefield of construction machinery. The reliability of the performance relates to the drivingsafety of the vehicle. Currently, the development of domestic off-highway mining dumptruck is mainly in the stage of the principle introduction and application. As manyproblems constantly revealed in the braking system during the customer use, the study ofthe performance characteristics has to be put on the agenda. In this paper, we carried outthe research on100t-off-highway-rigid-dump truck full hydraulic braking system featuresto enhance the reliability of the performance of braking system and the driving safety ofthe vehicle, which has important practical significance. The contents of the entire paperstudy are summarized as follows:Firstly, the working principle of the mining truck was analyzed. From the perspectiveof different operating conditions, hydraulic brake principle of the different brake form wasanalyzed in detail. And the fluid-filled storage and brake output process were emphaticallyanalyzed.Secondly, the operating characteristics and the structural principles of the keycomponents of the hydraulic brake system were analyzed. The analysis contained theperformance characteristics of priority unloading valve which control the liquid-filledpressure range and the operating characteristics of treadle valve which control the outputresponse of the front and rear axle brake. By creating mathematical models based on theforce balance and flow equations, the method of the accumulator charging pressure controland the static and dynamic pressure response of treadle valve were analyzed.Thirdly, the characteristics of the fully hydraulic braking system were simulated andanalyzed based on the AMESim (Advanced Modeling Environment for performingSimulations of engineering systems). The HCD (Hydraulic Component Design) simulationmodels of key components and the entire system simulation model were established. Aftersetting the simulation parameters in accordance with the structural dimensions of thecomponents, the dynamic characteristics including charging characteristics; the brakingpressure characteristics; the dynamic response characteristics; safety of the braking process etc. were simulated by AMESim.Fourthly, the experimental program was designed aimed at verifying the accuracy ofthe simulation results. The dynamic response of pressure of the charging process andbraking process were tested. The experimental results and simulation results of theanalysis were basically coincided which verified the accuracy of the theoretical inferenceand simulation analysis.Lastly, found the existing problem, proposed improvement program. The resultshowed that the rear axle braking response speed lagged behind the front one. The mainreason may be wet disc brakes during braking exclude service brake due to the gapbetween the piston and the friction disc. And then the performance of the rear axle brakingresponse was improved effectively by proposing a solution and verifying by theoreticalinference, simulation and experiment. |
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