Axial Piston Pumps, New Trends and Development

Abstract : Efficiency improvement is a key issue in any machine. The fluid power industry relies on volumetric pumps which need to pump high pressure fluid to a set of actuators located at different positions in a given device; the higher the pressure, the smaller the actuators need to be, therefore allowing to reduce the weight of the machine, being this, a critical issue in any flying device. At the present, the pumps which are able to produce the highest fluid pressure are piston pumps, and among the different sort of piston pumps, axial piston pumps seem to be the most widely used, probably due to its high efficiency and reliability. Pumps and motors overall efficiency, is in reality the product of volumetric, mechanical and hydraulic efficiency, therefore a decrease in any of these efficiencies will bring an overall efficiency decrease. In this book chapter, a deep study on the different axial piston pump moving parts shall be presented, equations clarifying leakage and pressure distribution in all axial piston pump moving parts will be introduced, and the dimensional parameters from which leakage depends will be clearly defined. As a result, a tool to improve piston pump volumetric efficiency shall be established. To validate the equations presented, a comparison between results produced by the equations, by several CFD models of each axial piston pump moving parts and several experimental measurements will be performed. Thanks to this comparison, the validity limits of the equations presented will be established. Thanks to the theory developed and the different test rigs used, a better understanding of the slippers dynamic behavior and barrel dynamics was gathered, pressure distribution, forces and torques generated in the slipper-swash plate, barrel-port plate and piston barrel will be presented, comparisons between CFD, analytical equations and experimental results will validate the new theory produced. One of the newest characteristics of the analytical, CFD and experimental development presented, is based on the performance of grooves being cut on slippers and pistons surfaces. The use of grooves is not fully extended, then each manufacturer decides whether or not they will be used for a given application. Nevertheless, a full understanding of its effect is not yet clarified. In the present chapter, the benefits and drawbacks of using grooves will be clearly established. Several dynamic models are also included in the present book chapter. The first model will focus on understanding the barrel dynamics. Some of the equations previously presented and validated will be included in the model and the barrel dynamic movement will be, thanks to this model and the experimental measurements performed, much better understood. A second model presented, will again use the new leakage equations developed and join them to create a full dynamic model of the entire axial piston pump. The model will be able to predict the output flow and pressure ripple, comparisons between numerical and experimental results are used to validate the new model created. Please notice that a total of three different state of the art test rigs have been used to validate all of the equations and models generated. At the end of the book chapter, some new trends on piston pumps and motors design, like new composite materials and the use of spherical slippers will be introduced. As a conclusion, the present book chapter has sub-chapters on: flat and tilt slippers with grooves, the use of grooves on pistons, barrel dynamics, piston-slipper spherical journal and an overall pump pressure and flow ripple model. New analytical equations, CFD models and state of the art test rigs will be presented. The aim is to give a tool to better design axial piston pumps and improve its efficiency.
Type de document :
Chapitre d'ouvrage
Angela S. Gomez-Ramirez and Jonathan C. E. Diaz. Hydraulics: Fluid Dynamics, Mechanical Applications and Role in Engineering, Nova Science Publishers, Chapter 1 - p. 1-157, 2012, 978-1-62257-246-5
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Contributeur : Magalie Prudon <>
Soumis le : lundi 10 juillet 2017 - 14:43:16
Dernière modification le : mardi 27 mars 2018 - 17:14:02

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  • HAL Id : hal-01559176, version 1

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Joseph M. Bergada, Sushil Kumar, John Watton. Axial Piston Pumps, New Trends and Development. Angela S. Gomez-Ramirez and Jonathan C. E. Diaz. Hydraulics: Fluid Dynamics, Mechanical Applications and Role in Engineering, Nova Science Publishers, Chapter 1 - p. 1-157, 2012, 978-1-62257-246-5. 〈hal-01559176〉

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