The Characteristics Of The Oil Film Of The Slipper/swash Plate Pair Of High Pressure Axial Piston Pump

Axial piston pump is widely used in various fields such as mining industry,shipbuilding industry,electric power industry and national defense industry because of its compact structure,high power density,easy variable control,and suitable for medium and high pressure and even ultra-high pressure working range.Among them,the three pairs of friction pairs,such as the sliding shoe pair,the plunger pair and the distribution pair,play an important role in the effective operation of the swash plate type axial piston pump.As the most complicated friction pair in the three major friction pairs,the sliding shoe pair is also the most vulnerable to friction and wear.There are two main reasons for the failure: First,due to the failure to properly match the pump and the hydraulic system,the oil film of the skid pair is subjected to too much impact load and is defeated;secondly,due to the unreasonable design of the structural parameters of the shoe,When subjected to the rated load,its structure is not enough to establish an effective oil support to form an effective oil lubrication,resulting in the occurrence of mixed friction or even dry friction,resulting in power loss of the shoe pair.Compared with the low-pressure axial piston pump,the high-pressure axial piston pump will produce relatively large load pressure and oil hydraulic pressure difference,so the friction and wear and power loss of the shoe pair will be more obvious.Investigating the intrinsic characteristics of the oil film of the sliding shoe and the influence of various factors on its characteristics play an important role in further improving the structure of the shoe,improving its performance and improving the service life.In this paper,a pair of swash plate type axial piston pump sliding shoe pair is taken as the research object to reveal the influence of the intrinsic lubrication characteristics,working parameters and structural parameters of the gap oil film on its characteristics:The 3D model of the internal structure of the swash plate axial piston pump was established by Solidworks software,and the model of the shoe pair model was theoretically modeled.Kinematic modeling analysis of a singleplunger-slide assembly,including macroscopic movement of its components in axial reciprocating and circumferential rotation,microscopic motion at any point on the bottom of the shoe;mechanical modeling analysis of the plunger sliding-shoe assembly It includes the static pressure that the components are subjected to at rest and the dynamic pressures during the movement.The theoretical model of the oil film of the skid pair gap is established,including the oil film thickness field,the pressure field and the force coupling model.On the basis of the establishment of the theoretical model,the matlab software is used to numerically calculate the overall theoretical model of the sliding shoe,and the compilation and debugging of the numerical calculation program code is completed.According to the numerical calculation results of matlab,the pressure field and thickness field variation law of the oil film rotation period of the sliding shoe are analyzed.The influence of each working parameter on the dynamic lubrication characteristics of the sliding shoe sub-oil film is analyzed.The working parameters considered in this paper are: load pressure,Drive shaft speed and swashplate tilt angle.It is concluded that the working parameter with the greatest influence on the characteristics of the oil film is the load pressure.On this basis,combined with the load pressure parameters to analyze the influence of the structural parameters of the sliding shoes on the dynamic characteristics and power loss of the oil film,the structural parameters of the sliding shoes considered in this paper are: the diameter and length of the damping hole,and the inner and outer radius of the sealing band.In addition,with the low power loss as a reference index,the approximate suitable range of the ratio of each parameter in each pressure interval is obtained.It is guaranteed that the structural parameter values selected in this range can effectively generate effective dynamic pressure support and lubrication on the bottom of the shoe,and can effectively reduce the power loss of the shoe pair,So as to speed up the design and production progress.