Paper XVIII(i) The influence of back-up rings on the hydrodynamic behaviour of hydraulic cylinder seals

Abstract

The main part of a hydraulic cylinder seal of compact type is the soft seal element. This is the part that usually is taken into consideration when calculation hydrodynamic proerties in the seal contact like oil film thicknesss, leakage flow and friction forces. In this work a symmetric piston seal with back-up rings is analysed. Calculations of oil film thickness, leakage flow and friction forces are carried out using the inverse hydrodynmic theory. Measured pressure distributions, for either the whole seal including the back-up rings, for one back-up ring at a time are used as input data. The purpose of this investigation is to determine how the oil film thickness, the leakage flow and the friction forces in the three contact zones are influenced by the back-up rings and the main seal element being coupled in series.