Abstract:As an important part of dump truck, the hydraulic lifting system has important effect on the performances of dump truck. The optimal model of the hydraulic lifting system was built and the optimal design and analysis was taken based on the optimal theory and MATLAB. Through ADAMS, the analysis model was established to verify the reliability of the optimal design. The lifting cylinder capacity and the lift force were chosen as the optimize goals, the lifting cylinder joint positions were chosen as design variables. Then the constraint conditions including boundary constraints, nointerfering constraint, a lift cylinder installation length constraint, maximum pressure constraints and other constraints were considered to optimize the mechanism. The test bench was built to verify the reliability of the optimal design model and results. The results show that: the lift cylinder installation length and maximum stroke are decreased 64% and 40% respectively, the maximum lift force and capacity are reduced 697% and 36% respectively, at the same time, the lifting time is reduced 726%; the first level and the second level bore are decreased 65% and 77%. Capacity reduction and bore decrease are benefit to flow decrease, oil pump selection and arrangement of the whole truck. The model and results provide reference for such design.