| With the rapid development of national economy and its steady increasing demand for energy and steel production, the mining scale and mining depth of open pit mines are growing, thus the transport conditions are deteriorating along. However the railway transportation is difficult to adapt to the transport requirements of deep mining by the limits of curvature radius, climbing ability and other factors. Therefore, the importance of large-scale mining dump trucks in the respect of mine transport is more and more prominent. Brake system is the key part to ensure safe operation of mining dump trucks. Its performance is directly related to transportation safety and operational efficiency of the dump truck because of the harsh road and working conditions.This paper takes the hydraulic brake system of an electric wheel dump truck which is being researched by Guangzhou Electric Locomotive Limited Company as study object. The structure and working principle of the brake system were deeply analyzed at first. Combined with the product samples of main components of the brake system, paper elaborated the work principle and performance characteristics of the brake pedal valve, electro-hydraulic proportional valve, relay valve and disc brake respectively.Paper modeled the main component parts of the brake system which includes brake pedal valve, electro-hydraulic proportional valve and relay valve and so on using HCD library in AMESim software based on black box theory and built the overall model of the hydraulic brake system. According to "Earth-moving machinery-Braking systems of rubber-tyred machines-Systems and performance requirements and test procedures"(GB/T21152-2007), the conditions of service brake and hydraulic brake while electric circuit fails were simulated. The simulation results show that the brake pressure and safe brake times of the hydraulic brake system satisfy the braking requirements in the case of the braking energy is provided by accumulators.As the implementing agency of the hydraulic brake system of a dump truck, disc bakes withstand a great deal of mechanical loads and thermal loads during braking. Paper established the FEM three-dimensional model of the disc brake on front axle of the dump truck and simulated its temperature field by Abaqus finite element software, and analyzed the distribution and variation of temperature field of the brake disc and friction block in detail. The results can provide a theoretical basis for further research of the disc brakes’ structural design and strength check consideration of thermal stress.In order to improve the efficiency of the thermal analysis of a disc brake, paper secondarily developed the thermal analysis of a disc brake based on Abaqus/Python to facilitate the study on the distribution, variation and its influencing factors of temperature field of the brake disc and friction block in the process of structural design and materials selection. |
PDF Full Text Request