ols the synchronous operation of the bending process and the positioning of the hydraulic cylinder when the machine is working at full capacity. I will take a certain type of universal Cable Tray Cold Roll Forming as an example to analyze the hydraulic system.
⑴The starting motor of the oil pump rotates in the direction marked by the pump arrow, that is, clockwise, to drive the axial piston pump to run, and the oil enters the valve plate and the electromagnetic overflow valve through the pipeline and returns to the oil tank. The oil in the lower chamber of the oil cylinder keeps the slide block at a fixed position.
(2)Downward movement The rapid downward movement of the Cable Tray Cold Roll Forming produces movement through the self-weight of the Cable Tray Cold Roll Double Layer Roof Forming Machine beam and accessories and the pressure of the oil. During this process, oil enters the rodless cavity of the hydraulic cylinder through the filling valve, and the rod cavity will generate back pressure, and the oil will flow back quickly. The fast-forward movement starts from the top dead center, and after a short deceleration stage, the speed of the slider slows down at a certain distance close to the bending plate.
⑶ Bending The bending stage begins with pressure build-up in the rodless cavity. On the one hand, the bending speed of Wuxi Shenchong is limited by the oil supply of the oil pump, on the other hand, it can be adjusted by the proportional valve direction valve. At the same time, the directional valve also controls the synchronous operation of the bending beam and the positioning of the bottom dead center. The limitation of bending force is accomplished by limiting the pressure of the pump through the proportional relief valve. The given values of corresponding speed, synchronization, positioning and pressure all come from the CNC.
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⑷Decompression The decompression of the rodless cavity starts when it reaches the bottom dead center, or after a short holding time, so that the material has enough time to form and further improves the dimensional accuracy of the workpiece. Both pressure maintaining and decompression are completed by the proportional directional valve according to the instructions of the numerical control. In order to improve processing efficiency, the decompression time must be as short as possible, but in order to avoid unloading impact in the whole system, it is required to extend the decompression time as much as possible. In short, the decompression curve should be as smooth as possible and not too steep. The optimization of the entire process is achieved through proportional directional valves.
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⑸Master cylinder return The flow rate of the pump and the pressure-bearing area of the rod chamber of the hydraulic cylinder determine the maximum return speed, which is close to the fastest speed in most cases. The return journey also requires synchronous operation, starting from the decompression of the rod chamber to the end of the top dead center. At the moment of the return stroke, it is required that the No. 8 YV2 electromagnet be reset for 2 seconds to realize pressure relief, and then the No. 11 YV3 and No. 24 YV6 electromagnets work, and the slider returns with a constant return speed.