| Axial piston pump plays an important role in the hydraulic system.Taking a4v25 series axial piston pump produced by Bosch Rexroth company as the main research object,based on the analysis of its hydraulic principle,this paper studies the working characteristics of piston pump under different port pair structures,aiming at improving the port distribution characteristics of piston pump,ensuring good lubrication,prolonging service life,reducing cavitation erosion phenomenon and reducing the noise of piston pump.The specific research contents are as follows:Firstly,the oil film theory of port pair is summarized,and the lubrication characteristics of oil film are simulated and analyzed by using computational fluid dynamics technology.The lubrication characteristics of plane oil film and spherical oil film are compared by pressure cloud,velocity cloud and temperature field cloud.The results show that: compared with the plane port,the spherical port can enhance the stability of the system,reduce the friction and wear and leakage,and prolong the service life of the port pair.Then,a new type of trapezoidal damping groove structure is designed.By controlling a single variable,the trapezoidal upper bottom,lower bottom and groove depth are taken as a single variable respectively.Through the simulation analysis of the internal flow field of the piston pump,the influence of different values of each variable on the performance of the piston pump is compared,and the optimal design size of the trapezoidal damping groove is determined.The results show that when the groove depth,upper bottom and lower bottom of the trapezoidal groove are 0.8 mm,0.5 mm and 0.8 mm respectively,the performance of the piston pump is relatively better,which paves the way for the comparison of the performance of the piston pump with other port pair structures.Secondly,according to the two different structures of the piston pump with spherical port and traditional plane port,the internal fluid domain of the piston pump with three different port pair structures is extracted and modeled respectively.The dynamic grid technology is used to simulate the movement of the piston cavity,and the simulation software CFD is used to simulate the internal fluid domain of the piston pump,and the comparison of three different port pair structures is made The oil film bearing capacity,pressure flow characteristics and cavitation characteristics of the plug pump are analyzed.Three types of port pair structure are:plane port pair with triangular damping groove,spherical port pair with triangular damping groove and spherical port pair with trapezoidal damping groove.The analysis results show that: in terms of oil film bearing capacity,the stress of spherical port pair is better than that of plane port pair,and the stress of spherical port pair with trapezoidal groove is better than that of triangular groove.In terms of pressure and flow pulsation,spherical flow distribution is better than plane flow distribution,and spherical flow distribution with trapezoidal groove is better than triangular groove.In terms of cavitation characteristics,there is little difference among them,and trapezoidal groove is slightly better.Finally,the static analysis of several port plates with different structures is carried out by using ANSYS Workbench software,and the maximum equivalent stress and maximum displacement deformation of port plates with different structures are obtained.Through the simulation to verify whether the different structure of the port plate can meet the design requirements of strength and stiffness.In addition,the spherical valve plate with triangular damping groove is analyzed separately,and the spherical radius is taken as a single variable to observe the influence of different spherical radius on the maximum stress deformation and maximum displacement deformation of the valve plate,so as to obtain the optimal design range of spherical radius. |
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