Numerical Analysis of the Dynamic Behaviour of Axial Piston Pumps and Motors Slipper Bearings

Borghi, Massimo; Specchia, Emiliano; Zardin, Barbara

doi:10.4271/2009-01-1820

Cited by 27 publications

(17 citation statements)

References 16 publications

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“…It becomes more convenient to express the displacement chamber pressure using a simple and discontinuous expression instead of solving the complicated differential equation presented in Eq. (6). Unlike the previous studies [32], the schematic method in this research considers the geometrical size of the kidney-shaped ports in the cylinder block, which makes the calculation of the displacement chamber pressure more accurate in this case.…”

Section: Mechanical Analysismentioning

confidence: 99%

“…Their proposed model was validated through measuring the oil-film thickness between the swash plate and slipper. Borghi et al [6] presented a numerical model for the dynamic behavior prediction of an over-clamped slipper, in which the slipper spin was taken into account. Using this numerical model, the effects of the slipper spin on the central oil-film thickness, tilting angle, and azimuth of the minimum oil-film thickness were analyzed.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Novel three-piston pump design for a slipper test rig

Zhang

Chao

et al. 2017

Applied Mathematical Modelling

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Slipper's micro motions including the squeezing motion, spinning motion, and tilting motion have a significant impact on its lubricating condition and dynamic behavior. However, few experimental studies are on these micro motions within a real axial piston pump, especially the slipper's spinning motion. The experimental investigations on the slipper in the past mainly focused on the parameters of the oil film such as pressure, thickness, and temperature. The sensors were often installed in the fixed swash plate when the cylinder block was chosen to rotate. Alternatively, the sensors were mounted in the fixed modified slipper when the swash plate rotated. The biggest challenge of the direct measurements of these micro motions is the space limitation for the sensor installation due to the compact structure of axial piston pumps as well as the slipper's macro motion. This paper presents a new three-piston pump for the slipper test rig which can provide enough installation space for the sensor. To realize the cylinder block balance, a hold-down plate is first introduced into this three-piston pump. In addition, a detailed set of relevant equations is derived to evaluate the functionality of the hold-down plate. Finally, the slipper's spinning motion was measured directly and continuously using this three-piston pump, which confirmed the capability of the slipper test rig.

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Section: Mechanical Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Novel three-piston pump design for a slipper test rig

Zhang

Chao

et al. 2017

Applied Mathematical Modelling

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“…Solving the Reynolds equation allows the determination of the pressure distribution within the gap. In cylindrical coordinates, the Reynolds equation is formulated with respect to the frame of reference as

\frac{1}{r^{2}} \frac{\partial}{\partial θ} ((), h^{3} \frac{\partial p}{\partial θ}) + \frac{1}{r} \frac{\partial}{\partial r} ((), r h^{3} \frac{\partial p}{\partial r}) = 6 μ ((), ω R_{c p} normalcos θ \frac{\partial h}{\partial r} - \frac{ω R_{c p} normalsin θ}{r} \frac{\partial h}{\partial θ} + ω \frac{\partial h}{\partial θ})

where p is the film pressure, μ is the oil viscosity, ω is the angular velocity of the spin, ω = 2πn / 60 , n is the shaft rotational speed and R cp is the pitch circle radius.…”

Section: Governing Equationsmentioning

confidence: 99%

Lubrication characteristics analysis of slipper bearing in axial piston pump considering thermal effect

Tang

Yin

2015

Lubr. Sci.

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In this study, the lubrication characteristics of a slipper bearing for axial piston pump considering oil thermal effect have been investigated. A mathematical model is developed to predict the film thickness and temperature on the slipper/swash plate interface under different operating conditions. Based on the mathematical model, a parametric study is conducted to evaluate the slipper lubrication performance. It is found that the slipper is characterised by an unstable behaviour and the behaviour is enhanced by lower pressure and higher rotational speed. As the film temperature increases rapidly due to high shaft speed and piston chamber pressure, the overall result is a rather low decline in the film thickness. The leakage flow rate increases with increasing speed or oil film thickness. The structure parameter can be optimised to obtain satisfactory slipper performance. Copyright © 2015 John Wiley & Sons, Ltd.

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“…Compared with other friction pairs of components, slipper pairs are special because they are the direct carrier of the piston cavity pressure, and therefore directly restrict the necessary high speed and high pressure of these pumps. Premature wear of the slipper pairs is one of the main factors affecting the service life of a piston pump [1][2][3]. Under challenging conditions such as high speed and high…”

Section: Introductionmentioning

confidence: 99%

Study on friction performance and mechanism of slipper pair under different paired materials in high-pressure axial piston pump

Zhao

et al. 2019

Friction

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High-pressure axial piston pumps operate in high-speed and high-pressure environments. The contact state of the slipper against the swashplate can easily change from an oil film lubrication to a mixed oil film/asperity contact, or even dry friction. To improve the dry friction performance of slipper pairs and to avoid their potentially rapid failure, this study examined the effects of material matching on the dry friction performance of the slipper pair for high-pressure axial piston pumps. A FAIAX6 friction and wear tester was developed, and the dry friction coefficients of the slipper pairs matched with different materials were studied using this tester. Based on the thermo-mechanical coupling of the slipper pair with the working process, the contact surface temperatures of the slipper pairs matched with different materials were calculated and analyzed for the same working conditions. Following this, the effects of the material properties on the temperature increase at the slipper sliding contact surfaces were revealed. The reliabilities of the temperature calculations and analysis results were verified through orthogonal tests of slipper pairs matched with different materials. The results indicate that the influence of the material density on the friction coefficient is greater than that of the Poisson's ratio or the elastic modulus, and that the slipper material chosen should have a high thermal conductivity, low density, and low specific heat, whereas the swashplate material should be high in specific heat, density, and thermal conductivity; in addition, the slipper pair should be a type of hard material to match the type of soft material applied; that is, the hardness of the swashplate material should be greater than that of the slipper material.

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Numerical Analysis of the Dynamic Behaviour of Axial Piston Pumps and Motors Slipper Bearings

Cited by 27 publications

References 16 publications

Novel three-piston pump design for a slipper test rig

Novel three-piston pump design for a slipper test rig

Lubrication characteristics analysis of slipper bearing in axial piston pump considering thermal effect

Study on friction performance and mechanism of slipper pair under different paired materials in high-pressure axial piston pump

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