Design And Optimization Of Non-valve-controlled Hydraulic Rock Drill

After analyzing the hydraulic rock drill development situation at home and abroad, this paper puts forward an improved new non-valve controlled gas liquid combined structure of hydraulic rock drill, which improves weight problem of the traditional valve control hydraulic rock drill; In addition, this structure uses the gas and liquid joint work, the backend impact mechanism of nitrogen chamber to absorb and release energy, which improve the performance and efficiency of the rock drill.Motion law of impact piston is very complex, which is difficult to be described with accurate mathematical model without simplification. Based on the assumption of ideal circumstances, the structure of the linear mathematical model is established, relation between the abstract design variables αand the gas and liquid ratio φ is deduced.With the minimum peak flow rate as the optimization target, design is optimized and the scope of the abstract design variable α is narrowed down. On this basis, the paper calculates hydraulic impact mechanism, slewing mechanism and propulsion of the non-valve controlled hydraulic rock drill, deduces formula of the key structure parameters.According to the design requirements and the deduced calculation formula above, the structural parameters of the non-valve controlled hydraulic rock drill is calculated. Furthermore, AMESim model is set up and the simulation is run to get the results of simulation according to the working principle of no valve control hydraulic rock drill, but the simulation results cannot meet the design requirements. After analyzing the reason of being unable to meet the design requirements, the paper puts forward four improved schemes: the orifice oil control plan, oil inlet control plan, oil outlet control plan, duplex line control plan. By AMESim simulation analysis, it is concluded that the other three kinds of scheme can effectively improve the performance of the no valve control hydraulic rock drill and work efficiency except oil inlet control plan, of which the duplex line control plan has the most obvious improvement in performance and efficiency. After analyzing the effect of various parameters on the change rock drill, result shows that when the ratio λof high and low voltage of the nitrogen chamber is smaller, the property of rock drill is the better, but the volume of the nitrogen chamber is the bigger. In order to get the best performance, the initial volume of the nitrogen chamber should be selected according to the actual situation when designing; The quality of the Impacting piston has an optimal value range, out of this range can lead to no reaching the best performance and efficiency; Working pressure and flow of the system also have an optimal value range. When less than this range, the rock drill cannot boot normally, cannot meet the design impact energy and impact frequency either; When greater than the scope, the single impact energy and impact frequency of rock drill has a small increase, which lead to the decrease of the efficiency of system due to the increase of the input energy.The paper puts forward a set of swappable non-valve controlled hydraulic rock drill measurement and control scheme. The scheme can test and control the four schemes by changing the electromagnetic-valve opening and closing and opening of the throttle valve. The scheme can also adjust the system pressure of work and the work flow by controlling the double proportional valve, and obtain each scheme optimum system pressure and the optimum system flow through the repeating contrast test.The research and analysis above has a certain reference value and reference for the structure of non-valve controlled hydraulic rock drill both in the research and production.