Energy improvement of fineblanking press by valve-pump combined controlled hydraulic system with multiple accumulators

To improve the useful energy efficiency of a hydraulic fine-blanking press (HFBP), a hydraulic system using a combined valve-pump combined with multiple accumulators and comprising a valve-controlled circuit and pump-controlled circuit, was presented based on the working-process load characteristics. By adopting multiple accumulators, the slide block mechanical energy was recycled and the system dynamic response speed was improved. The system operation principle was first presented, and the system parameters were calculated based on the energy conservation law. Then, a simulation model was established to analyze the system energy dissipation and distribution. Finally, the proposed system was validated on a 1000-ton HFBP. The results demonstrate that, in comparison with the conventional system, the novel system performs well, while simultaneously achieving a high working speed, high precision and large tonnage. Moreover, the total dissipation energy of this novel system was decreased by approximately 100 kJ in a working cycle, while the energy utilization efficiency was increased by an average of 20% under different load conditions. This novel system can be generalized to any hydraulic press to improve energy efficiency and especially hydraulic presses having a large tonnage.