Title:Investigation of a closed electro-hydraulic hybrid driveAuthor(s):Peter Ladner, Karl Ladner, Rudolf Scheidl, Hagen StrasserAbstract:In the last decade a new drive technology evolved, namely to combine speed controllable electrical motors with application specific hydraulic circuits for motion control to exploit in this way the advantages of both drive technologies and to avoid their disadvantages. Sometimes such drives are called hybrid. A specific realization of such a drive featuring a fully closed hydraulic circuit and a compact arrangement is investigated in this paper. From a design methodological viewpoint it represents a true module with a minimum of couplings which in this case are only mechanical and electrical connections. There is no external hydraulic connection Lifetime critical components such as ball screw- or threaded spindles of typical electromechanical drives and proportional- or servo valves, cooler, filter and even a tank of conventional hydraulic drives are missing. A test bench of such a drive was set-up. Besides demonstrating the main functionality concerning dynamics and precision hydraulic fluid degradation and contamination, entrapped air, and wear of the pump and the valves have been the main objectives of the experiments with this test bench. Meanwhile the hybrid drive was tested under very severe load conditions for more than 4000 hours. Despite a missing filter and a very low amount of hydraulic fluid neither the fluid nor the hydraulic components show critical signs of deterioration or wear, respectively.Booktitle:Proceedings of the 11th Scandinavian International Conference on Fluid Power, SICFP'09ISBN:978-91-02-7393-588-3Page Reference:14 page(s)Publishing:6/2009