Research On The Dynamic Lubrication Characteristics Of The Slipper/swash-plate Pair In Axial Piston Pump

As an important transmission components,the axial piston pump are faced with an urgent demand for higher power transmission,and its displacement,pressure and rotating speed need to be improved.Slipper/Swash-plate pair,one of the main friction pairs,bacames a significant limitation of performance improvement in the piston pump.The lubrication mechanism of slipper pair is complicated,coupling with complex dynamics and tribology.It is very difficult to accurately predict the lubrication characteristics of slipper in the real pump,which hinders the improvement of the design method.In this paper,the theoretical and experimental research on the dynamic lubrication characteristics of the slipper/swash-plate pair is carried out.The lubrication mechanism is deeply analyzed and the mathematical model is established to explore the various factors that affect the lubrication.Finally,an actual pump test rig is set up to realize the test and model verification of the lubrication characteristics,which provides the basis for the slipper/swash-plate pair optimization design.Firstly,the paper analyzes the working principle of the slipper pair,discusses the mechanism of various lubrication effects,and analyzes the importance of the squeezing effect in the process of dynamic lubrication of slipper/swash-plate pair.Then the Reynolds equation is build up under the column coordinates.The external force and overturning moment of slipper during the actual pump operating are analyzed,and it is clear that the lubricating oil film is the only source of balancing external force and overturning moment.Subsequently,a simplified model of dynamic lubrication of slipper/swash-plate was established to analyze the influence factors of dynamic lubrication quickly.Taking into account the key impact of slipper tilting on lubrication,a dynamic lubrication model was established for more comprehensive lubrication analysis.According to the dynamic lubrication model of slipper/swash-plate,the different adaptability of the slipper/swash-plate pair lubrication to different working condition are analyzed.The structural factors that affect the dynamic lubrication characteristics of the slipper are discussed,which provides the theoretical reference for the optimization design of the slipper/swash-plate pair.Through the simulation of this model,the minimum film thickness in one cycle and the distribution of the minimum film thickness on the swash plate surface are analyzed,in order to analyze the dangerous area of the slipper.Then the slipper spin is analyzed.The mechanism and the effect of the spin on the lubrication are discussed.The basic model is established to calculate the spin speed of the slipper.Finally,the scheme of dynamic lubrication characteristic test is discussed and confirmed.And the test rig is set up.Taking lubricant film thickness as the main measurement parameter,the lubrication characteristics of the slipper/swash/plate pair under the conditions of load pressure,rotation speed and charge pressure are studied experimentally.After the dynamic characteristic test,the wear condition of the swash plate was observed.According to the macro appearance on the friction surface of theswash plate,the accuracy of the model was further verified.Then,the phenomenon of slipper spin is observed by using a high-speed camera,and the spin model of the slipper is preliminarily confirmed.