Technical Committee Lubricants
Investigation of the friction and wear behaviour of different hydraulic fluids in a test rig for mechanical testing of hydraulic fluids — Substitution of the vain-cell-pump test according to DIN 51389
The investigation of the lubricity of hydraulic fluids in line contact of the MPH-3 test rig has shown that fluids of different lubricity can be distinguished by means of friction, wear and scuffing limit determination. The investigation has further shown that the setting of the test parameters load and speed in the line contact at the start-up of the test rig and their increase up to the nominal load and speed have significant effects on the tribocontact and must therefore be reproduced very accurately from test to test. The investigation of the lubrication capabilities of hydraulic fluids using a line contact showed, that a distinction between different fluids regarding their lubrication capabilities can be made, using friction-, wear- and erosion tests (galling). The test showed furthermore that the pressure and relative velocity of the line contact during the start-up phase and the slope of these parameters up to nominal values have an ample effect on the tribocontact, thus requesting a high reproducibility of these parameters from test to test. The high reproducibility of the boundary conditions during different tests was achieved by steady design modifications of the test rig and the development of a software for fully-automatic control of the test procedure. The main objective of the project, which was the development of a test rig for mechanical testing of hydraulic fluids, which produces reproducible and distinguishable results of the lubrication capability of hydraulic fluids, was obtained.