Experimentelle und numerische Modellbildung zur Bestimmung der Reibkraft translatorischer Dichtungen

  • Experimental and numerical modelling to determine the friction force of reciprocating seals

Heipl, Oliver Pascal; Murrenhoff, Hubertus (Thesis advisor)

Aachen : Shaker (2013)
Dissertation / PhD Thesis

In: Reihe Fluidtechnik : D 72
Page(s)/Article-Nr.: VI, 132 S. : Ill., graph. Darst.

Zugl.: Aachen, Techn. Hochsch., Diss., 2013

Abstract

Hydraulic and pneumatic linear actuators move unsteady when they start-up from a standstill or a reversal of the direction occurs at the end of the stroke. In high dynamic special applications, the friction significantly affects the moving behaviour. In contrast to previous steady-state investigations, the seal friction is considered in the context of this work as a function of acceleration. For this purpose, experimental as well as numerical methods are developed. Measurements of the friction forces of hydraulic rod seals are carried out using a test rig driven by a crank mechanism. The results for different seal geometries, varying pressures and temperatures at speeds of up to 10 m/s are discussed. In addition, a newly developed measurement principle for pneumatic rod seals is designed and enables to detect the seal friction with minimised disturbances. The influence of seal geometry, material, installation situation, pressure, grease and seal dimensions are systematically investigated using the pneumatic test rig. Due to the increasing importance of analytical and numerical methods in the development process of sealing systems, two simulation approaches are presented to calculate the friction force. The well-known inverse hydrodynamic approach (IHL) is a simplified calculation method, whereas the developed elastohydrodynamic model (EHD or EHL) allows a physically more accurate reproduction. Finally, comparisons between measurements using an O-ring operated at different conditions and corresponding simulations show the suitability of the numerical models for hydrodynamic lubrication conditions.

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