Study On Characteristics Of Electrically Poportional Bent Axis Constant Pressure Piston Variable Pump

The bent axis variable displacement pump has the advantages of large displacement,large output pressure range and strong self-priming.It is widely used in hydraulic systems such as construction machinery,metallurgical machinery,mining machinery and ships.As the power source of the hydraulic system,the efficiency of the bent axis piston pump largely determines the overall energy efficiency of the hydraulic system.In constant pressure variable pump,one end of the pressure control valve is connected with the outlet of the hydraulic pump.By adjusting the spring compression at the other end of the pressure control valve,the outlet pressure of the pump is kept constant.The output flow of the pump varies with the load demand,so as to avoid the capacity loss caused by the excess flow flowing back to the mailbox through the relief valve,which is of great significance for energy saving of the hydraulic system.The traditional constant pressure variable displacement pump controls the set pressure of the pump by manually adjusting the spring compression.The pressure adjustment is inconvenient,and it is not suitable for the field with high automation requirements.Therefore,this paper studies a way of remote control of outlet pressure of bent axis pump by using electric proportional relief valve.By adjusting the setting pressure of proportional relief valve,the outlet pressure of variable piston pump can be adjusted in real time.It has the advantages of simple structure and convenient control.In the first chapter,This paper introduces the general situation and research status of variable control modes of bent axis pump and axial piston pump,and introduces the future development trend of variable control modes.The necessity of researching electric proportional constant pressure bent axis pump is pointed out,and the research ideas and contents of this subject are determined.In the second chapter,according to the motion law of constant pressure variable displacement pump,the mathematical models of plunger motion and force,the mathematical models of inlet and outlet of valve plate,and the transfer function of variable system of constant pressure variable bent axis pump are established,and the stability of variable mechanism is verified by Simulink software.In the third chapter,Based on Wade hydraulic A7 V bent axis constant pressure variable displacement pump,its three-dimensional mechanical model is established.The three-dimensional model is imported into SimulationX software platform,and the electro-hydraulic joint simulation model is established.In the fourth chapter,the motion characteristics of the plunger and the fluctuation characteristics of the whole pump pressure and flow are simulated and analyzed,and the influence of the parameters of the triangular groove of the valve plate on the pressure and flow characteristics of the single plunger is simulated and analyzed,and the appropriate range is obtained.In the fifth chapter,the dynamic and static characteristics of the constant pressure variable displacement bent axis pump are simulated and analyzed.Taking response time and overshoot as indicators,the parameters of variable cylinder spring preloading force,core area and piston diameter are optimized,and the parameters optimization interval is obtained.The sixth chapter,summarizes the main research results of the paper,and points out the shortcomings of the paper and the next research direction.