Research On Process And Quality Control Method Of Abrasive Flow Precision Machining The Inner Surface Of Valve Sleeve

The rapid development of aerospace and automotive transmission fields has put forward higher requirements for the stability and reliability of the hydraulic system,and the processing quality of the valve largely determines the reliability of the hydraulic system.However,the precision valve sleeve has a large number of small diameter cross-holes.The burrs at the cross-holes and the processing quality of the inner wall surface of the valve sleeve seriously affect the working performance of the hydraulic system.Therefore,the abrasive flow precision machining method is used to finish the inner wall surface and cross-holes of the valve sleeve in this thesis,and the process of machining the inner surface of the valve sleeve with the abrasive flow is established.The quality control method of the inner surface of valve sleeve with abrasive flow precision machining is built,which lays a foundation for the development of abrasive flow precision machining technology.In this thesis,a suitable sub-grid model is adopted by the large eddy simulation method,and the numerical simulation analysis is carried out for the valve sleeve workpiece under three different mold core structures,different processing parameters,and side hole outflow conditions.1)For different flow channel structure models,the thesis analyzed the static pressure,velocity distribution law,wall shear force,and pressure produced by particles on the wall surface in the flow channel.It is found that in the process of the abrasive flow processing the inner surface of the valve sleeve,under the inclined core structure,the material removal from the particle to the wall surface is more uniform and the surface quality is higher;2)Under the inclined core structure,the different processing parameters of processing pressure and the mesh of abrasive particles are selected to perform numerical simulation analysis on the process of abrasive flow machining.It is found that the inner surface of the valve sleeve to predict the material removal efficiency and surface processing quality.Under different processing pressures,the influence of wall shearing force,speed,dynamic pressure and the existence of vortex on particle flow are analyzed;Under the conditions of different abrasive mesh,the analysis focuses on the influence of wall shear and particle pressure on the cutting action of the wall.Through analysis,the mechanism of abrasive particles on the wall surface in the process of abrasive particle precision machining of the inner wall surface of the valve sleeve is obtained,and the law of the influence of different parameters on the wall surface processing quality is revealed.3)With the side hole as the boundary condition,under the condition of different flow rates and viscosities,the influences of fluid strain rate,velocity vector,and wall shear force on the fillet radius of the cross-hole edge,burr removal,and radial hole wall machining quality are analyzed.It is found that the lower the fluid viscosity and the higher the speed;the larger the radius of the cross-hole edge,the higher the viscosity,and the higher the speed,the higher the processing quality of the side hole wall.The response surface design method is used to test the process of abrasive flow machining the inner surface of the valve sleeve.The test results show that the processing pressure and the mesh of abrasive grains have a significant effect on the abrasive flow machining.Through the quadratic response surface map and contour map of the parameters,the minimum point of the roughness,and the optimal process parameters for abrasive flow processing the inner surface of the valve sleeve are obtained by using the response optimization method.The inner surface roughness value of the valve sleeve after precision machining by the abrasive flow can reach 0.218?m,and it is found that the material removal is not obvious when the number of abrasive grains is large,and the surface of the workpiece will be scratched if the machining pressure is too high.At last,the method of variance analysis is used to establish a roughness prediction model.The surface quality changes after abrasive flow machining can be predicted by controlling the level of parameters.A quality control method for the inner surface of the valve sleeve for abrasive flow machining is proposed.The valve sleeve side hole is taken as the outlet boundary condition,the influence law of the radial hole wall and edge processing quality is explored,and it is found that the fillet radius of the cross-hole edge is larger after processing with high-speed and lowviscosity fluid.In order to ensure that the cross-hole edge has a smaller fillet,the low-speed and high-viscosity fluid should be selected for the best processing effect.