The Flow Rate Characteristics of External Gear Pump for EHPS

EHPS(Electro-Hydraulic Power Steering) system generates the steering operation force from the electric motor connected directly to the oil pump. When developing the steering system, the final specification of steering system is determined through the field test and the tuning process of the several times. In this paper, the flow rate measurement of an external gear pump was performed. Then by using the experimental results, an approximate model expressed by flow rate characteristics was proposed to calculate the discharge flow rate. The proposed approximate model was verified by comparison with the experimental data and AMESim results. As the experimental data and AMESim results agree well, the approximate model data can be used as an alternative to the highly expensive experimental procedure.