Research Papers: Hydrodynamic Lubrication

A Transient Thermoelastohydrodynamic Lubrication Model for the Slipper/Swashplate in Axial Piston Machines

[+] Author and Article Information
Andrew Schenk

Department of Agricultural and
Biological Engineering,
Purdue University,
225 S. University Street,
West Lafayette, IN 47907
e-mail: schenka@purdue.edu

Monika Ivantysynova

Department of Agricultural and
Biological Engineering,
Purdue University,
225 S. University Street,
West Lafayette, IN 47907
e-mail: mivantys@purdue.edu

Contributed by the Tribology Division of ASME for publication in the JOURNAL OF TRIBOLOGY. Manuscript received August 20, 2014; final manuscript received January 24, 2015; published online March 13, 2015. Assoc. Editor: Daniel Nélias.

J. Tribol 137(3), 031701 (Jul 01, 2015) (10 pages) Paper No: TRIB-14-1209; doi: 10.1115/1.4029674 History: Received August 20, 2014; Revised January 24, 2015; Online March 13, 2015

A transient lubrication model has been developed for the sliding interface between the slipper and swashplate in axial piston hydraulic pumps and motors. The model considers a nonisothermal fluid model, microdynamic motion of the slipper, as well as pressure and thermal deformations of the bounding solid bodies through a partitioned solution scheme. The separate contributions of elastohydrostatic and elastohydrodynamic lubrication are studied. Although hydrostatic deformation dominates, hydrodynamic effects are crucial for actual operation. Finally, the impact of transient deformation on lubricant pressure is explored, with its consideration necessary for accurate analysis.

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Fig. 1

Cross section of an axial piston pump [1]

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Fig. 2

Free body diagram of the slipper [1]

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Fig. 3

Slipper fluid film discretization

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Fig. 4

Illustration of slipper pocket pressure control volume

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Fig. 5

Illustration of the solid body deformation pressure loads and constraints

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Fig. 6

Illustration of moving swashplate deformation

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Fig. 7

Swashplate pressure deformation

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Fig. 8

Thermal boundary conditions for the slipper and swashplate

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Fig. 9

Flow diagram of the complete numerical scheme

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Fig. 10

Hydrostatic (320 bar pocket pressure) pressure deformation of the slipper

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Fig. 11

Mean absolute slipper (a) and swashplate (b) total and hydrodynamic-isolated deformation

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Fig. 12

Simulation results of exploded slipper fluid film thickness

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Fig. 13

Simulation of exploded slipper fluid film thickness neglecting transient deformation squeeze pressure contributions

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Fig. 14

Slipper film thicknesses (a) transient deformation effects considered in Reynolds formulation and (b) no transient deformation consideration

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Fig. 15

Slipper film thicknesses with a rigid swashplate (a) transient deformation effects considered Reynolds formulation and (b) no transient deformation consideration

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Fig. 16

Comparison of rigid-swashplate simulations with (a) the full model and (b) the slipper transient deformation neglected




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