Research On Key Technologies And Dynamic Simulation Of Multi-ring Axial Piston Pump

With the development of hydraulic technology and popularization of water mediator, more and more attentions were paid to the application of axial piston pump. But 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, Li shiliu, the Professor of Chongqing University, brought forward the concept of multi-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 not only widen variable range, but also effectively realizes large flow output and constant-power in speed transformation. But as a new style, the design of multi-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 multi-ring axial piston pump can be applied in the hydraulic system depend on how to effectively reduce the mass of cylinder block, prevent the pistons from clipping in the cylinder block and slippers 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 differences of double-ring axial piston pump, and adopted modern design method, took the multi-ring for example, lucubrated the key technologies of multi-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 multi-ring axial piston pump in the structural, part design, friction and lubrication, control leakage and noise; Besides, here also emulated the mechanism and fluid character of the multi-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 set up. 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, stiffness 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 fat liquor film theory were used to present a static pressure support mode with four-support and double-damp hole. And we introduce leakage factorζof multi-support-type double-damp-hole plunger, derive designing formula of multi-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 coefficient 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.④According to the feature of port plate assignment of multi-ring axial piston pump, designed a port plate that can prevent the impact and an assistant support of port plate based on optimization center spring pre-pressure.⑤Adopted modern design method, modeled the multi-ring axial piston pump in three dimensions, and emulate the mechanism both in static state and movement.⑥In view of the axial piston pump cavitation, we use software named pumplinx firstly to analyze fluid dynamic characteristics of multi-ring axial piston pump. According to the results of the analysis, we present the measures such as surface style of left end cap, brought forward an effective solution to the cavitation problem, and provide a useful reference for the structural design of multi-ring axial piston pump.