Development of the Rexroth High-Pressure Piston Pump Test for Hydraulic Fluid Qualification

It is difficult, if not impossible; to select any single test that will model the expected performance of any hydraulic fluid in a wide range of hydraulic pumps made by many different manufacturers. Increasing pressures often encountered in new hydraulic pump applications compounds this problem. However, some basic assessment of hydraulic fluid performance is necessary for numerous reasons such as: developing an appropriate fluid purchase policy, international standard development, fluid classification and others. Since the now-classic standard tests such as: ASTM D-2882, DIN 51389 and others are simply inadequate for this task and also since the manufacturer, Eaton Inc., no longer manufactures these pumps, it has been necessary to develop an alternative testing strategy [1, 2 and 3]. The Bosch-Rexroth Corporation has developed a high-pressure piston pump test that has been an excellent predictor of hydraulic fluid performance for many years. This test is currently being developed as a proposed candidate for an ASTM Standard Test and is the subject of this report.