The Design And Analyze Dynamic Characteristics Of Double-ring Axial Piston Pump

At present, in order to realize variable flow, the hydraulic system which applied axial piston pump and motor generally depends on flow regulating valve or swash plate.The result of applied these two types is limited variable flow,small range of variable speed and surplus power.So ,the problem is it can not realize lower speed but large flow output and constant-power in speed transformation.Inresponse to these contradictions , brought forward the concept of double-ring axial piston pump and designed the principle machine. Besides its variable flow by the swash plate, multi-ring axial piston pump makes the second variable flow to the system for adding the working piston,which widen variable range. But as a new style,the design of double-ring axial piston pump is far more complicate than the single.The design exists independence and relating between the design of any one component, and also between components. So, whether double-ring axial piston pump can be applied in the hydraulic system depend on how to efectively reduce the mass of cylinder block,prevent the pistons from clipping in the cylinder block and silppers from slipping away,the parameters design of port plate and balance the overturn moment.After aggregating domestic and overseas research results of single-ring axial piston pump, this paper combined itself diferences of double-ring axial piston pump, and adopted modern design method, lucubrated the key technologies of double-ring axial piston pump in optimization of cylinder block, how to prevent the pistons from clipping in the cylinder block and slippers from slipping away,the parameters design of port plate, and derived the theoretical formula of double-ring axial piston pump in the structural,part design,fiction and lubrication,contorlle akage and noise; Besides, here also emulated the mechanism and fluid character of the double-ring axial piston pump.The specific contents of this study are as follows:①The structure model of the cylinder is analyzed and a mathematical model of a double-ring axial piston pump to the cylinder is setup .Structural optimization is done for cylinder with reducing the quality of the cylinder as the purpose, the cylinder block structure restrict as boundary conditions and cylinder strength, stifness and strength of contacts between the cylinder and piston conditions as boundary conditions.②In view of the problem that plunger blocks cylinder,static pressure and the fatliquor film theory were used to present a static pressure support mode with four -support and double-damp hole.And we introduce leakage factorζof double-support-type double-damp-hole plunger, derive designing formula of double -ring axial piston pump plunger, and design the structure of double-ring pistons of double-ring axial piston pump. Also we do the optimum design the gap between the plunger on the basis of four-support and double-mode damping static pressure.③Slipper is designed on the theory of static support and the decrease coeficient is proposed to do the optimal design to the center spring pre-pressure in view of the problem that multi-slice axial piston pump light from the boots,and the pre-pressure becomes optimal.④According to the feature of port plate assignment of double-ring axial piston pump,designed aport plate that can prevent the impact and an assistant support of port plate based on optimization center spring pre-pressure,and equilibrium the Overturning moment of cylinder.⑤Adopted modem design method,modeled the double -ring axial piston pump in three dimensions,and analyzed velocity and acceleration distribution for the piston ,obtained the curve for in and out pistons'velocity and acceleration distribution.And analyzed different pistions'dynamic characteristics , obtained the pistons'velocity and pressure distribution at different conditions.