POWER LOSS IN THE LUBRICATING GAP BETWEEN CYLINDER BLOCK AND VALVE PLATE OF SWASH PLATE TYPE AXIAL PISTON MACHINES
Keywords:
lubricating gaps, cylinder block-valve plate, axial piston pump, waved surface, energy dissipationAbstract
The lubricating gaps are the primary source of energy dissipation in piston machines. The paper presents results of a simulation study that investigates the effect that a wave-like micro surface shape variation applied to the valve plate gap surface has on power loss in the cylinder block-valve plate interface. Special attention is given to the relation between gap height, operating parameters, surface design and power loss. The effect of waved surface amplitude and frequency is also studied. Results indicate that power loss in the cylinder block-valve plate interface can be reduced by over 50 % on account of the waved surface compared to the standard cylinder block-valve plate interface design. The effect of the waved surface is most significant at low operating pressures. A special in-house code has been used for this research study. The simulation model covers fluid-structure interaction and micro motion of the cylinder block resulting from oscillating piston forces. Details of the model are explained. The model predicts the pressure and velocity fields generated in the lubricating film and calculates leakage, viscous friction and power loss.
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References
Baker, J. 2008. Power Losses in the Lubricating Gap
between Cylinder Block and Valve Plate of Swash
Plate Type Axial Piston Machines, MS thesis, Purdue
University.
Baker, J. and Ivantysynova, M. 2008. Investigation of
Power Losses in the Lubricating Gap between Cylinder
Block and Valve Plate of Axial Piston Machines,
Proc. 5th Fluid Power Net International
PhD Symposium, Krakow, Poland, pp. 302-19.
Baker, J. and Ivantysynova, M. 2009. Advanced
Surface Design for Reducing Power Losses in Axial
Piston Machines, Proc. 11th Scandinavian International
Conference on Fluid Power, Linköping, Sweden,
Vol. 10 (2009), No. 2, pp. 15-30.
Bergada, J. M., Watton, J. and Kumar, S. 2008.
Pressure, Flow, Force and Torque Between the Barrel
and Port Plate in an Axial Piston Pump, Journal
of Dynamic Systems, Measurement and Control,
Vol. 130, pp. 011011-1-011011-16.
Berthe, D. and Godet, M. 1973. A More General Form
of Reynolds’ Equation-Application to Rough Surfaces.
Wear, Vol. 27, pp. 345-57.
Burton, R. A. 1963. Effects of Two-dimensional, Sinusoidal
Roughness on the Load Support Characteristics
of a Lubricant Film. Transactions of the
ASME, Journal of Basic Engineering, vol. 85, pp.
-64.
Dowson, D. and Ehret, P. 1999. Past, Present and
Future Studies in Elastohydrodynamics. Proceedings
of the Institution of Mechanical Engineers,
PT.J. Journal of Engineering Tribology, Vol. 213,
No. J5, pp. 317-33.
Fatu, A., Hajjam, M. and Bonneau, D. 2005. An
EHD Model to Predict the Interdependent Behavior
of Two Dynamically Loaded Hybrid Journal Bearings.
Journal of Tribology, Vol. 127, No. 2, pp.
-24.
Fredrickson, A. 2008. A Study of the Piston and Cylinder
Interface of an Axial piston Pump Using an
Advanced Computer Model. MS thesis, Purdue
University.
Hamrock, B. J., Schmid, S. R. and Jacobson, B. O.
Fundamentals of Fluid Film Lubrication, 2nd
Edition. Marcel Dekker, Inc. New York.
Hargreaves, D. J. 1991. Surface Waviness Effects on
the Load-carrying Capacity of Rectangular Slider
Bearings. Wear, Vol. 145, pp. 137-151.
Harris, M. R., Edge, K. A. and Tilley, D. G. 1993.
Predicting the Behaviour of Slipper Pads in Swashplate-
Type Axial Piston Pumps. ASME Winter Annual
Meeting, New Orleans, Louisiana. 93-
WA/FPST-3.
Huang, C. and Ivantysynova, M. 2003. A New Approach
to Predict the Load Carrying Ability of theGap Between Valve Plate and Cylinder Block. Bath
Workshop of Power Transmission and Motion Control
PTMC 2003, Bath, UK, pp. 225-39.
Ivantysyn, J. and Ivantysynova, M. 2001. Hydrostatic
Pumps and Motors. Academic Books International,
New Delhi.
Ivantysynova, M. 2001. Energy Losses of Modern
Displacement Machines - A new approach of Modelling.
Seventh Scandinavian International Conference
on Fluid Power, Linköping, Sweden, pp. 377-
Ivantysynova, M. 1999. A New Approach to the Design
of Sealing and Bearing Gaps of Displacement
Machines. Fourth JHPS International Symposium
on Fluid Power, Tokyo ’99, pp. 45-50.
Ivantysynova, M., Huang, C. and Behr, R. 2005.
Measurements of Elastohydro-Dynamic Pressure
Field in the Gap Between Piston and Cylinder. Bath
Workshop on Power Transmission and Motion Control
PTMC 2005, Bath, UK, pp. 451-465.
Jouini, N. and Ivantysynova, M. 2008. Valve Plate
Surface Temperature Prediction in Axial Piston
Machines. Proc. 5th Fluid Power Net International
PhD Symposium, Krakow, Poland, pp. 95-110.
Lasaar, R. and Ivantysynova, M. 2005. An Investigation
into Micro- and Macrogeometric Design of Piston/
Cylinder Assembly of Swash Plate Machines.
International Journal of Fluid Power, Vol. 5, no. 1,
pp. 23-36.
Lebeck, A. O., Teale, J. L., and Pierce, R. E. 1978.
Hydrodynamic Lubrication and Wear in Wavy Contacting
Face Seals. Journal of Lubrication Technology,
Vol. 100, pp. 81-91.
Lebeck, A. O. and Young, L. A. 1989. Wavy-Tilt-
Dam Seal Ring. US Patent 4836561.
Manring, N. D. 2000. Tipping the Cylinder Block of
an Axial-Piston Swash-Plate Type Hydrostatic Machine.
Journal of Dynamic Systems, Measurement
and Control, Vol. 122, pp. 216-221.
Patir, N. and Cheng, H. S. 1978. An Average Flow
Model for Determining Effects of Three Dimensional
Roughness on Partial Hydrodynamic Lubrication.
ASME Journal of Lubrication Technology,
Vol. 100, pp. 12-17.
Pelosi, M. and Ivantysynova, M. 2009. A Novel
Fluid-Structure Interaction Model for Lubricating
Gaps of Piston Machines. Proceedings of the Fifth
Fluid Structure Interaction Conference, Crete. pp.
-24.
Rasheed, H. 1998. Effect of Surface Waviness of the
Hydrodynamic Lubrication of a Plain Cylindrical
Sliding Element Bearing. Wear, Vol. 223, pp. 1-6.
Roccatello, A., Mancò, S. and Nervegna, N. 2007.
Modelling a Variable Displacement Axial Piston
Pump in a Multibody Simulation Environment.Journal of Dynamic Systems, Measurement and
Control, Vol. 129, pp. 456-468.
Ruddy, A. V., Dowson, D. and Taylor, C. M. 1982.
The Prediction of Film Thickness in a Mechanical
Face Seal with Circumferential Waviness on both
the Face and the Seat, Journal Mechanical Engineering
Science, Vol. 24, no. 1, pp. 37-43.
Vaidya, A. and Sadeghi, F. 2008. Hydrodynamic Lubrication
of Scroll Compressor Thrust Bearing with
Grooves and Circular Pockets. Proc. ASHRAE Annual
Meeting, Salt Lake City, USA.
Yu, T. H. and Sadgehi, F. 2001. Groove Effects on
Thrust Washer Lubrication. Journal of Tribology,
Vol. 123, pp. 295-304.
Wieczorek, U. and Ivantysynova, M. 2002. Computer
Aided Optimization of Bearing and Sealing Gaps in
Hydrostatic Machines - The Simulation Tool CASPAR.
International Journal of Fluid Power, Vol. 3,
No. 1, pp. 7-20.
Wohlers, A. and Murrenhoff, H. 2007. Tribological
Simulation of a Hydrostatic Swash Plate Bearing in
an Axial Piston Pump. Bath Workshop on Power
Transmission and Motion Control PTMC 2007,
Bath, UK, pp. 129-141.
Zhao, H., Choy, F. K. and Braun, M. J. 2005. Dynamic
Characteristics and Stability Analysis of a
Wavy Thrust Bearing. Tribology Transactions,
:1, pp. 133-139.