Lubrication Characteristics Of Slotted Port Pair For Floating Cup Pump

Floating cup pump and traditional axial piston pump working principle is similar,are the use of cylinder and piston relative movement between the volume of the cavity,complete oil suction and oil discharge,both of them use the relative movement between cylinder and piston to change the cavity volume and complete oil suction and discharge.The biggest difference is that the traditional piston pump makes the piston move along the axial direction when the cylinder is fixed,floating cup pump is the opposite,the floating cup pump makes the flouting cup move back and forth along the axial direction when the piston is fixed.Its unique working principle has significant advantages in reducing pulsation and noise,balancing axial force and radial force,improving lowspeed performance and reducing cost,especially service life.Its special structure eliminates the radial force between the plunger and the floating cup and reduces a pair of friction pairs.However,the floating cup pump has not been industrialized so far,and the friction failure of the port pair composed of the barrel plate and the valve plate is one of the important influencing factors.The research and development status and structural characteristics of floating cup pump are analyzed and combed,especially the lubrication and friction failure of the end face slotting of the floating cup pump port pair is studied,and the leakage characteristics of the slotted port pair on the end face of the floating cup pump are studied,which will provide important theoretical support for the performance improvement and promotion of floating cup piston pump.In this paper,the lubrication characteristics of the slotted port pair on the end face of the floating cup pump are studied by combining theoretical analysis and numerical simulation.The main contents are as follows:1)Firstly,the kinematic law of the floating cup pump is analyzed,and the theoretical calculation formula of axial motion,velocity and displacement of the floating cup are determined,and then the flow state of the key fluid domain is deduced and analyzed.Secondly,by analyzing the leakage characteristics of floating cup pump,the theoretical basis of analyzing the lubrication characteristics of port pair by comprehensively considering the pressure and leakage characteristics of oil film is put forward.Then,based on the classical lubrication theory,a connected stepped groove structure is designed at the end face of the barrel plate.By analyzing the structure and action mechanism of the connected stepped groove,comparing the pressure flow characteristics of different groove types,the pressure distribution law of the end face of the barrel plate is deduced,and the compression force and separation force of the flow port pair are calculated.2)A three-dimensional geometric model of the floating cup pump was established,the fluid domain was extracted and meshes were carried out,reasonable boundary conditions were set for numerical simulation.the grid independence is verified to ensure the high accuracy of the calculation results.the convergence judgment of numerical simulation ensures that the calculation results have converged.The numerical simulation results are verified to ensure the accuracy of the floating cup pump model.3)The influence of end face slotting on lubrication characteristics of floating cup pump valve pair was analyzed,and the influence of structural parameters and working conditions parameters on oil film pressure was compared and analyzed.The results show that the shallow cavity depth ratio has a great influence on the dynamic pressure;The increase of the wrap angle of the stepped groove will improve the bearing capacity of the oil film,but too large wrap angle will reduce the volumetric efficiency.4)The leakage characteristics of the end slotted port pair are analyzed,and the effects of various parameters on the leakage are compared and analyzed.Based on the orthogonal experimental design,the influence weight of groove parameters on lubrication characteristics and the best groove parameters are obtained through range analysis,it is found that the wrap angle of the stepped groove has the greatest influence on the lubrication characteristics,the depth of the deep cavity is 0.4 mm,the depth ratio of the shallow cavity is 1.5,the damping groove with equilateral triangular section,and the wrap angle of the stepped groove is 24°,which is the best parameter of the connected stepped groove,and the total pressure is increased by 7.9%.