Working Principle of Hydraulic System of Bending Machine


Hydraulic bending machine is generally used in the industry for the bending of plates, and the strength is controlled according to the system parameters to achieve different bending effects. The structure includes a support, a workbench, and a clamping plate. The workbench is placed on the support. The workbench is composed of a base and a pressing plate. The base is connected to the clamping plate through a hinge. The base is composed of a housing, a coil, and a cover plate. The coil is placed In the recess of the seat shell, the top of the recess is covered with a cover plate.


Working principle of hydraulic system of the bending machine:

1. Start

All electromagnets must not be energized, and the output oil of the main pump is unloaded through the middle of valves 6, 21.


2. The main cylinder goes down quickly


The electromagnets 1Y and 5Y are energized, the valve 6 is in the right position, and the hydraulic control check valve 9 is opened by the control oil through the valve 8. Oil inlet: pump 1-valve 6 right-valve 13-upper cavity of the master cylinder. Oil return path: lower cavity of master cylinder-valve 9-right position of valve 6-middle position of valve 21-oil tank.


The slider of the main cylinder descends rapidly under its own weight. Although the pump 1 is in the maximum flow state, it still cannot meet its needs. Therefore, the upper cavity of the master cylinder forms a negative pressure, and the oil from the upper oil tank 15 enters the upper cavity of the master cylinder through the filling valve 14.


3. The main cylinder approaches the workpiece slowly and pressurizes


When the slider of the master cylinder drops to a certain position and touches the stroke switch 2S, 5Y loses power, and valve 9 is closed. At this time, the pressure in the upper chamber of the master cylinder rises, the valve 14 is closed, and the master cylinder slowly approaches the workpiece under the action of the pressure oil supplied by the pump 1. After contacting the workpiece, the resistance increases sharply, the pressure further increases, and the output flow of the pump 1 automatically decreases.


4. Keep pressure


When the pressure in the upper chamber of the master cylinder reaches a predetermined value, the pressure relay 7 sends a signal to de-energize 1Y, the valve 6 returns to the neutral position, and the upper and lower chambers of the master cylinder are closed. The conical surfaces of the check valve 13 and the filling valve 14 ensure a good seal It keeps the main cylinder pressure. The holding time is adjusted by the time relay. During the pressure holding period, the pump is unloaded at the center of the valves 6 and 21.

Operation precautions of hydraulic bending machine:



1. During operation, the pressed workpiece should be placed in the middle and parallel to the upper and lower molds, and the cushion should be stable. During the working process of the bending machine, it is strictly prohibited to overhaul or adjust the mold.



2. When pressing long and large workpieces, two persons (or more) are required to operate. Avoid toppling when the workpiece is deformed due to the force and deformation. It is not allowed to hold the pressed workpiece at close range.



3. When calibrating or pressing the workpiece, the workpiece should be placed in the middle of the mold, and no bias is allowed. The upper die should approach the workpiece slowly to prevent the workpiece from being forced out.



4. Always check whether the strokes of the two cylinders are the same during work, otherwise adjust or report for repairs in time. When the piston of the oil cylinder is shaken or the oil pump screams, the air in the oil circuit must be discharged.



5. Always pay attention to the oil tank and observe whether the oil level is suitable. If the oil level is too high, check the oil return line and adjust the oil return valve. It is strictly forbidden to overflow the oil tank. Keep working oil temperature ≤45℃.



6. When the control valve and safety valve fails or the safety protection device is not perfect, it is not allowed to continue working.



7. Regulating valves and pressure gauges are strictly prohibited to be adjusted by others, and the operator must tighten them after adjustment.



8. When the working pressure is too high, the oil return valve must be checked and adjusted, and work can only be carried out after the fault is eliminated.



9. It is strictly forbidden for the upper die of the hydraulic sheet metal bending machine to exceed the maximum stroke.



10. During work, it is strictly forbidden to reach into the middle of the upper and lower molds.



11. Frequently check the travel switch and safety protection device of the hydraulic sheet metal bending machine to ensure the reliable operation of the machine.



12. When adjusting the mold or overhauling, the oil pump must be turned off to ensure safety.



13. When using a crane to lift the workpiece, strictly abide by the safety technical operating regulations for the implementation of the crane operation and ground (hook) operation, and cooperate closely.