In this paper, the design of hydraulic actuating circuit of doing over-running load was performed. Generally, the counter balance valve has been used to protect over-run or free falling of acuating system. But sometimes, it makes some undesirable problems such as pressure surge or vibration. To overcome such problems and satisfy the system requirements, we suggest the hydraulic circuit actuated by servo valve. In order to verify the properness of suggested hydraulic circuit, hydraulic actuator with servo valve was modeled using ADAMS/Hydraulic which is a commercial dynamic analysis software for multi-body system. Also, the effectiveness of hydraulic actuating circuit was verified via test bed and real plant.

Generally it is needed to have a multi stage drawing operation to increase a drawing ratio. So, this study is about the hydraulic circuit design of the 3 stage deep drawing machine. As the drawing ratio is large or deep, the quality of deep drawing products are affected more by the force and velocity of the press cylinder. Therefore using the computer simulation, the pressure reponses which are related to the force and velocity of press cylinder are analysed, and the design of the hydraulic circuit are proposed. The results of simulation shows that it correspond to experiments and have good feasibility. Proposed hydraulic circuit can be used to improve the quality of a deep drawing products.