Theoretical And Experimental Research On Friction And Lubrication Characteristic Of Textured Port Plate Pair

The port plate pair is one of the key components, and it is employed by the hydraulic powercomponent and the hydraulic actuator which adopt the way of end plane flow distribution, such asaxial piston motor, vane pump and other products. Along with the hydraulic drive system developingto high speed, high pressure, working performance and service life of the port plate pair is put forwardhigher request. Surface texture technology becomes worldwide research focus on tribology because ofits performance of increase loading capacity, decrease friction coefficient, reduce wear and improvelubricating property, its successful application of the mechanical seal, the engine piston ring, thecomputer hard drive, etc. provides a new thought for improve tribological performance of the portplate pair. The tribological performance of the textured port plate pair is studied in both theory andexperiment in this paper, and it can offer guidance for the design of the textured port plate pair.In theory: The textured port plate pair’s lubrication model based on its construction features and theactual working condition is established, the textured parameters such as the micro-pit’s depth, themicro-pit’s diameter, the area ratio on the oil load capacity is analyzed, it can provide a basis fordecreasing friction coefficient and reducing wear. On account of cavitation, the textured port platepair’s leakage model is established, a new computing way to the textured port plate pair’s leakage isfound, and it can provide reference for mechanical seal. the textured port plate pair’s dynamic modelis established and dynamic simulation is performed based on the software of Matlab/Simulink, thechange of the oil film thickness is analyzed by the theory.In experiment: Based on the working principle of the axial piston pump, a textured port plate pair’swear tester is developed. For the complex structure of the port plate, Micro-pits manufacture processand procedure by the use of photolithography combined with electrolytic etching process is found.The suitable working condition and the textured parameters is selected by the conclusions fromtheoretical analysis and physical condition, and the experiment can be carried out.From theoretical analysis and experimental study, the conclusions are be show as follow:On the aspect of the textured port plate pair’s oil film characteristics: The textured port plated pairhas a higher oil loading capacity, the optimal area ratio is related to the ratio of the micro-pit depth tothe oil film thickness, the larger micro-pit can produce the larger oil loading capacity, it has the largestoil loading capacity when the oil film thickness is equal to the micro-pit depth, with the oil filmthickness reducing, the oil film stiffness has a sharply increase.On the aspect of the tribological performance of the textured port plate pair in low pressure area: the optimal area ratio can be effected by multiple factors, in the same environment the area ratiowhose value is10%and15%has a better tribology performance. The value of micro-pit diameter is100μm, the better tribological performance can be got, the largest value of reducing the wear and tearis37.35%. the value of the micro-pit depth is10μm, the largest value of reducing friction is27.98%.On the aspect of the all textured port plate pair’s tribological performance: when the value of thearea ratio is10%or15%, the all textured port plate pair has a similar tribological performance, whenthe value of the micro-pit is200μm, the all textured port plate pair has a better tribologicalperformance, its anti-friction mechanism can be decided by the surface texture’s three basic role ofcontaining solid particles, dynamical effect and second lubrication.On the aspect of the all textured port plate pair’s leakage: The micro-pit depth and the area ratiohave large effect on the all textured port plate pair’s leakage, with an increasing the micro-pit depth,the leakage will reduce. Under the same area ratio and micro-pit depth, with an increasing themicro-pit diameter, the leakage will increase.On the aspect of the all textured port plate pair’s dynamic characteristics: In contrast to theuntextured port plate pair, the all textured port plate pair have better dynamic characteristic, itsdynamic characteristic is closely related to the oil film stiffness, when the less oil film thickness, theall textured port plate pair have an obvious advantage to prevent dry friction.The research findings in this paper show that the textured port plate can improve the performanceof the friction and lubrication, it can refer for hydraulic components such as gear pump’sbushing/shell, the flow divider pintle which withstand unbalanced axial hydraulic pressure.