An experimental study on the friction behaviour of aircraft hydraulic actuator elastomeric reciprocating seals

摘要

This study is on reciprocating elastomeric seals for use in aircraft linear hydraulic actuator assemblies where reliability of operation is of critical importance. Work has been carried out using an optical seal specific rig simulating the high pressure working conditions that a reciprocating seal encounters. The rig has provided friction measurements using transducers while simultaneously providing detailed 2-D contact images using a horoscope optical arrangement. The effect of pressure and stroking velocity on the friction of the seal is studied. Other effects such as complex flow patterns, leakage and wear in the seal contact are observed and discussed. It is found both through measurements and images that high pressure conditions encourage the development of thicker films and more effective lubrication takes place at higher pressures. The effect of speed is not significant for the range of speeds in the tests. Particularly of concern are actuator start-up and slow-down cycles when surface adhesion effects lead to high friction. These conditions are present in real applications and the overall reliability of the seals is dictated by these cycles.