Slipper Balance in Axial Piston Pumps and Motors

Koç, Erdem; Hooke, C. J.; Li, K. Y.

doi:10.1115/1.2920946

Cited by 52 publications

(17 citation statements)

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“…The effects of slipper spin, tangential velocity, tilt, slipper non flatness, inlet orifice, and conditions for metal to metal contact, amongst others, have been investigated. The performance of composite slippers working with water based fluids has been studied by Li and Hooke [15] and the torque created on the spherical piston slipper interface and its effect onto the slipper dynamic performance has also been considered [1,2,16]. Slipper dynamic performance over one complete revolution was investigated by [17,18] finding a large variation in slipper central clearance and tilt depending on piston connection with tank or outlet ports.…”

mentioning

confidence: 99%

The hydrostatic/hydrodynamic behaviour of an axial piston pump slipper with multiple lands

Bergadà¹,

Watton

Haynes

et al. 2009

Meccanica

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mentioning

confidence: 99%

The hydrostatic/hydrodynamic behaviour of an axial piston pump slipper with multiple lands

Bergadà¹,

Watton

Haynes

et al. 2009

Meccanica

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“…[−3µωαr m1 sin θ r 2 + k 1 ]dθ [11] r m1 = r 1 + r 0 2 [12] First land: r 1 < r < r 2 p 2 = −3µωαr m2 sin θ r 2 2(h 02 + αr m2 cos θ ) 3 + k 3 (h 02 + αr m2 cos θ ) 3 ln(r) + k 4 [13] …”

Section: Flow and Pressure Distribution On Multiple Land Slippers Mamentioning

confidence: 99%

Leakage and Groove Pressure of an Axial Piston Pump Slipper with Multiple Lands

Bergadà¹,

Haynes

Watton

2008

Tribology Transactions

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This article presents a new analytical model, based onReynolds equation of lubrication, to evaluate the leakage and pressure distribution for an axial piston pump slipper taking into account the effect of nonvented grooves. The equations consider slipper spin and tilt and are extended to be used for a generic slipper with any number of grooves. A test rig has been designed and used to check experimentally the applicability of the theoretical equations and comparisons between theoretical and experimental results show a good agreement. The new theory can predict slipper leakage and pressure inside the groove with a high level of accuracy, especially at the very low slipper tilts that exist in practice. Experimentally, it is demonstrated that although a groove maintains a constant pressure along its path, under abnormal conditions the pressure differential can exist inside the groove. The effect of tangential velocity on groove pressure and slipper leakage is then studied experimentally, showing that as the rotational speed increases, there is a small decrease in leakage and a small increase in the average pressure inside the groove.

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“…They investigated the oil film pressure distribution and load characteristics by considering the pressure-viscosity effect of the lubricant, the pressure-elasticity effect of the lubricating surface, and the properties of dynamic stiffness in the oil film. G. Rizzo et al Koc et al (1992) and Hooke (1989) carried out an experimental and theoretical investigation of the effects of deformation in slipper pad, clamping ratio, and orifice size on the load-carrying capacity of hydrostatic thrust bearing under a low-speed condition in axial piston pumps and motors. They concluded that polishing of the running face to a slightly convex form appeared to be essential for successful operation under all conditions; the orifice in under-clamped slippers could increase the clearance and destabilize the slipper, which would result in the slipper becoming sensitive to the effect of tilting couples; the design for over-clamped slippers seemed to depend on the precise value of the clamping ratio and the width of the slipper land.…”

Section: Introductionmentioning

confidence: 99%

Axial piston pumps slippers with nanocoated surfaces to reduce friction

Rizzo

Massarotti

Bonanno

et al. 2015

International Journal of Fluid Power

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This paper shows the experimental results obtained using a nanocoating (developed by ISTEC-C.N.R.) applied to the slippers of an axial piston pump to reduce the friction losses in order to improve the pump overall efficiency map. It is well known that the mechanical power losses in a hydraulic pump come from the friction between parts in relative motion. The need to provide, especially at low rotational speed, hydrodynamic lift causes power losses in terms of volumetric and mechanical efficiency, due to the contrasting need to increase leakage to provide lubrication and to keep a minimum clearance in meatus to limit the volumetric losses. The application of special surface treatments have been exploited in pioneering works in the past, trying different surface finishing or adding ceramic or heterogeneous metallic layers, but the potential of structured coatings at nanoscale, with superhydrophobic and oleophobic characteristics, has never been exploited. Using a dedicated test rig developed at IMAMOTER-C.N.R., able to ensure hydrostatic working condition during the mutual rotation between the slippers and the swash plate, the functional performance of the nanocoated slippers' surface have been studied. In the first part of the paper, the functionalization method is presented; in the second part, a comparison between the experimental performances of coated and uncoated surfaces is showed.

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Slipper Balance in Axial Piston Pumps and Motors

Cited by 52 publications

References 0 publications

The hydrostatic/hydrodynamic behaviour of an axial piston pump slipper with multiple lands

The hydrostatic/hydrodynamic behaviour of an axial piston pump slipper with multiple lands

Leakage and Groove Pressure of an Axial Piston Pump Slipper with Multiple Lands

Axial piston pumps slippers with nanocoated surfaces to reduce friction

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