The Research Of Hydraulic System On NC Control Multi-point Die-cushion

Since 1980's, the higher requirement of presses for huge sheet metal forming in auto industry, which promotes the development of multi-point die-cushion of hydraulic presses. The key equipment of multi-point presses is NC controlled hydraulic die-cushion. Based on sheet forming requirement, force always be controlled by hydraulic die-cushion. In this paper, on the base of researching the program of blank holder force, the hydraulic system of hydraulic die-cushion is designed. By math model and simulating, we ensure the hydraulic system works well. The paper's main content:In chapter 1, the importance of NC controlled hydraulic die-cushion is introduced. Then, the development and trend of presses are discussed. The blank holder force is also introduced. In the end, the meaning and the main content of this paper are summarized.In chapter 2, the key conception of hydraulic pressure forming and blank holder force are introduced, the programs of generating blank holder force are concluded by contrast.In chapter 3, the control curve of hydraulic system was presented, the work principle of each sequence, especial the pre-acceleration and the blank holder force processing, are analyzed. The hydraulic system is calculated and the main components are chosen. Auxiliary power system and the releasing heat of hydraulic system are calculated.In chapter 4, the methods of simulation are introduced. To satisfy the work requirement, the pre-acceleration processing and blank holder force processing are modeled and simulated.In chapter 5, sum up the whole paper and prospect the next step work.On the base of researching programs of blank holder force, firstly, the hydraulic system is design in this paper; then, by modeling and simulation, the hydraulic system that satisfied the work requirement is built up; In the end, we prospect the next step work.