Research On Optimization Design Of External Helical Gear Pump Based On Pumplinx

Because of its simple structure,high efficiency and low price,gear pump is widely used in various engineering fields and is the most common hydraulic pump on the market.However,due to its own structure,the gear pump has the phenomenon of trapped oil which seriously affects the stable operation.As an important type of gear pump,helical gear pump is obtained by changing the tooth shape.Because of the existence of the helix angle,the helical gear pump can theoretically change the helix angle or tooth width to affect the coincidence degree of the gear mesh to eliminate the oil trapping phenomenon.This paper takes the external meshing helical gear pump as the research object,simulates the internal flow field of the pump based on Pumplinx software,discusses whether changing the coincidence degree can completely eliminate the trapped oil phenomenon,and carries out a comparative analysis with the traditional method of opening the unloading groove.The influence of important parameters such as helix angle,tooth width and radial clearance on the performance of helical gear pump is studied by simulation.It provides a certain reference and basis for the design optimization of external helical gear pump in the future.The main research contents of this paper are as follows:Firstly,based on the working principle of helical gear pump,a method of changing the helix angle or tooth width to affect the coincidence degree and eliminate the oil trapping phenomenon is proposed.The instantaneous flow characteristics of the pump are analyzed theoretically,and the effects of different helical angle and tooth width on the flow characteristics of the helical gear pump are compared.Secondly,the internal flow field of the external helical gear pump is simulated by using the method of combining Pumplinx and Scorg,which avoids writing complex UDF functions and reduces the consumption of calculation.The change rule of relevant physical parameters with time is analyzed through the calculation results.Then,with the gear parameters unchanged,change the helix angle and tooth width,and study the change rule of the performance of the external helical gear pump with different helix angle and tooth width before reaching the critical value through simulation.According to theoretical and simulation calculations,the critical values of helical angle and tooth width of the helical gear pump are analyzed and determined.The internal flow field of the pump under five states of no unloading groove,double unloading groove,single unloading groove,critical helix angle and critical tooth width is simulated and studied,and the influence of different methods to eliminate oil trapping on the performance of helical gear pump is compared.The results indicate that the effect is best at the critical helix angle.Finally,the radial clearance leakage model of helical gear pump is established,and the optimal radial clearance is solved with the goal of minimizing the total power loss,and the influence of spiral angle and tooth width on the optimal radial clearance is studied.The performance changes of helical gear pump with different radial clearance and eccentricity are studied by simulation.Analysis shows that eccentric installation of gear pairs can effectively improve the performance of helical gear pumps.