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.
EN