The hydraulic system of the shearing machine mainly consists of an axial piston pump and an integrated system of plug-in valves. The required pressure oil for the system is supplied by the axial piston pump, and the high working pressure of the system is 20MPa. The return of the tool holder is completed by an accumulator, and the inflation pressure of the accumulator is about 6-8 MPa.

　　1、 Working principle of hydraulic system:

　　1. Cutting: Electromagnetic valve YV2 is powered on to change direction, and the system establishes pressure; The pressure oil first enters the pressure oil cylinder to press the sheet metal; Next, the pressure oil enters the upper chamber of the left cylinder, and the tool holder descends; The oil in the lower chamber of the left cylinder enters the upper chamber of the right cylinder, and the oil in the lower chamber of the right cylinder is pressed into the accumulator for storage. Due to the approximately equal area of the lower chamber of the left oil cylinder and the upper chamber of the right oil cylinder, the left and right sides of the tool holder descend synchronously.

　　2. Return journey: After the knife holder reaches the bottom dead center, all solenoid valves lose power, the oil pump unloads, and the knife holder returns to the top dead center under the action of the accumulator; The pressure cylinder is reset under the action of the spring.

　　3. Shear angle increases: When solenoid valve YV3 is powered on, the series chamber is connected to the system, and the system is in an unloaded state. Under the action of the accumulator, the right cylinder moves upward, and the oil in the upper chamber of the right cylinder is discharged to the oil tank, resulting in an increase in shear angle.

　　4. Shear angle reduction: Electromagnetic valves YV1, YV2, YV3 are energized, valve 2 unloading port is closed, system pressure is established, valve 1 is closed, the channel between the upper chamber of the left cylinder and the system is disconnected, pressure oil enters the upper chamber of the right cylinder, the right cylinder descends, and the shear angle is reduced.

　　Before adjusting the shear angle, the gate valve 8 in front of the accumulator must be closed. After adjusting the shear angle, the knife should be operated overhead 1-2 times before cutting again.

　　5. Accumulator oil filling: When the tool holder returns slowly and the pressure gauge on the accumulator shows a low value, the accumulator needs to be filled with oil.

　　6. Exclude the air in the series oil chamber: If the pipeline between the lower chamber of the left cylinder and the upper chamber of the right cylinder has been disassembled during machine maintenance, then there must be air mixed in this area. Therefore, after restarting the oil pump, the air in this area must be eliminated first.