Abstract: When using the relevant empirical value and safety factor to design the hydraulic system parameters of doubletriangular drill boom, problems such as high system pressure, large pressure resistance level of hydraulic components, serious system heating, high manufacturing and maintenance cost, and high power consumption exist. To address these problems, the structure of the doubletriangular drill arm is theoretically analyzed, the extreme position of the doubletriangular load in the process of the drill arm movement is calculated using the methods of motion trajectory projection and static analysis, and the oil cylinder load parameters at the extreme position are obtained. Then, a load sensitive hydraulic system is designed based on the working principle of doubletriangle structure and the working environment of boom. The principle of the system and the main parameters of hydraulic components are determined through theoretical analysis and calculation. The test results show that the load parameters of the hydraulic system at the extreme position of motion are basically consistent with the theoretical analysis parameters, the overall operation of the system is stable and reliable, and the adjustment function of the servo cylinder is normal. The temperature rise of the hydraulic system in the tunnel for 3 hours is 65.5 ℃, which validates the rationality and applicability of the design of the hydraulic system.

Key words: doubletriangle drill boom, hydraulic system, mechanical analysis, parameter design