Pushing the Performance Limits of the Lubricating Interfaces in … · 2019. 7. 1. · Cylinder Block/Valve Plate Interface Performance Investigation through the Introduction of Micro-Surface

Meike Ernst

Advisor:

Formerly Dr. Ivantysynova

Currently Dr. Vacca

6/6/2019

Maha Fluid Power Research Center

1500 Kepner Dr.

Lafayette, IN 47905

Pushing the Performance Limits of the Lubricating Interfaces in Axial Piston Machines

2

Micro Surface Shaping

Shaping the component surfaces that form the lubricating interfacesShape is on the order of microns in height

Fluid Film

Surface Shape

u

Component A

Component B

3From the work of Andrew Schenk (2014)

FluidSlipper Solid Body

Swashplate Solid Body

Translation

Tilt

Relative motion of components builds

hydrodynamic pressure.

Load support

Translation and tilt can increase leakage

Load Support and Power Loss at the Interfaces

4

Table of Contents

I. Three main lubricating interfacesII. Slipper-swash plate interfaceIII. Cylinder block-valve plate interfaceIV. Piston-cylinder interfaceV. Conclusions

5

1. Slipper-swash plate interface2. Cylinder block-valve plate interface3. Piston-cylinder interface

These lubricating interfaces have two important functions:

• Bearing function• Sealing function

The Lubricating Interfaces of Axial Piston Machines

Slipper

Piston Swash PlateCylinder Block

DC Valve Plate

1

2

32 1

Overview Slipper-Swash Plate Cylinder Block-Valve Plate Piston-Cylinder Conclusions

a piston pump CAE toolF TI

6

Slipper


DC Valve Plate

1

1

Slipper-Swash Plate Interface


7

The Slipper

Slipper


DC Valve Plate

1

1

Slipper-Swash Plate Interface


Sealing Land

Piston

Slipper Swash Plate

8

Trace 1

Trace 2Trace 8

Trace 3

Trace 4

Trace 5

Trace 6

Trace 7

Measuring Slipper Wear

Hei

ght

[m

]Normalized Distance along Trace

0 1


From the work of Ashkan Darbani (2019)

9

Variables:v0, v1, x0

𝑠1 = 𝑎1𝑥2 + 𝑏1𝑥 + 𝑐1

𝑠2 = 𝑎2𝑥2 + 𝑏2𝑥 + 𝑐2

x0

v0

v1

Slipper Surface Shaping

10



10

Variables:v0, v1, x0

𝑠1 = 𝑎1𝑥2 + 𝑏1𝑥 + 𝑐1

𝑠2 = 𝑎2𝑥2 + 𝑏2𝑥 + 𝑐2

x0

v0

v1


Slipper Surface Shaping

10

50 % Decrease in Power Loss

at 450 bar, 3,600 rpm, 100% Displ.

Optimized Profile


11

Optimization Results (Cont.)



12

Slipper


DC Valve Plate

1

2

2

Cylinder Block-Valve Plate Interface


13

12

Cylinder Block Valve Plate

Figure from Baker (2008)

Circumferential Sine Wave Surface Shape

Circumferential Sine Wave Surface Shape:


From the work of Rene Chacon (2014)

14From the work of Rene Chacon (2014)

Results


~40% reduction in power loss

15

The Lubricating Interfaces of Axial Piston Machines

Slipper


DC Valve Plate

13

Piston-Cylinder Interface


Half-Barrel

Axial Sine Wave

Waved Barrel

Circumferential Sine Wave

Piston Surface Shaping to Increase Efficiency

“Flat”


From the work of Ashley Wondergem (now Dr. Busquets) (2018)

Half-Barrel

Waved Barrel

Operating Condition:350 bar, 1,500 rpm, 20% Displacement

Over 50% reduction in power loss

Over 20% reduction in power loss

75 cc UnitNominal clearance reduced to

~60% of original unit

Piston Surface Shaping to Increase Efficiency


From the work of Ashley Wondergem (now Dr. Busquets) (2018)

18

Water Hydraulics

Why Water???

Green (sustainable resource) Cheap Widely available

Water Hydraulics


19

Bushing

Cylinder Block

zK

Pump Case

External Forces on Piston Head

Piston During the High-Pressure Stroke

Metal-Metal Contact


Pt. A

Pt. B

DC Fluid

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Piston Deformation during the High-Pressure Stroke

DC Pressure

Current Work



21


DC Pressure

Current Work



22


DC Pressure

Current Work



xpr

ypr

23

Conclusions

• The Maha Fluid Power Research Center in-house model:o State of the art multi-physics simulation toolo Today’s presentation focused on its virtual prototyping

capabilities

• Well-designed surface shaping can:o Drastically reduce power losso Increase achievable load support for low-viscosity fluids

• Surface shaping is the FUTURE:Advances in manufacturing allow for more complex shaping


24

Questions?

25

ReferencesBusquets, A. (2018). An Investigation of Micro-Surface Shaping on the Piston/Cylinder Interface of Axial Piston

Machines, PhD thesis, Purdue University.Chacon Portillo, R. (2014). Cylinder Block/Valve Plate Interface Performance Investigation through the Introduction of Micro-

Surface Shaping, Masters thesis, Purdue University.Darbani, A. A. (2019). An Investigation in Slipper-Swashplate Interface of Axial Piston Machines, Masters thesis,

Purdue University.Ernst, M. and Ivantysynova, M. (2018), ‘Axial Piston Machine Cylinder Block Bore Surface Profile for

High-Pressure Operating Conditions with Water as Working Fluid’. 2018 Global Fluid Power Society PhD Symposium (GFPS). Samara, 18-20 July.

Ivantysyn, J., and Ivantysynova, M., 2003, Hydrostatic Pumps and Motors, Tech Books International, New Delhi, pp. 134-141, Chap. 4.

Ivantysynova, M., Garrett, R. A. & Frederickson, A. A. (2012), ‘Positive Displacement Machine Piston with Wavy Surface Form’. Lasaar, R. (2003), Eine Untersuchung zur mikro- und makrogeometrischen Gestaltung der Kolben-/Zylinderbaugruppe von Schraegscheibenmaschinen, VDI Verlag GmbH, Duesseldorf.URL: http://www.sciencedirect.com/science/article/pii/S0257897205008807

Lasaar, R. (2003), Eine Untersuchung zur mikro- und makrogeometrischen Gestaltung der Kolben-/Zylinderbaugruppe von Schraegscheibenmaschinen, VDI Verlag GmbH, Duesseldorf.

Pelosi, M. (2012), An Investigation on the Fluid-Structure Interaction of Piston/Cylinder Interface,PhD thesis, Purdue University.

Schenk, A. (2014). Predicting Lubrication Performance between the Slipper and Swashplate in Axial Piston Machines, PhD thesis, Purdue University.

Pushing the Performance Limits of the Lubricating Interfaces in … · 2019. 7. 1. · Cylinder Block/Valve Plate Interface Performance Investigation through the Introduction of Micro-Surface

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