Use methods of pressure relay
First for safety protection, the pressure relay is set at one end of the clamping hydraulic cylinder. After the hydraulic pump starts, the workpiece is clamped first. At this time, the pressure in the right cavity of the clamping hydraulic cylinder rises. When the pressure relay rises to the set value, the pressure relay acts and sends out an electric signal to turn on the 2YA, so the cutting hydraulic cylinder enters cutter cutting. During machining, the normally open contact of the pressure relay micro switch is always closed. If the workpiece is not clamped, the pressure relay is disconnected, and the 2YA power is cut off, the cutting hydraulic cylinder immediately stops feeding, avoiding the accident that the workpiece is not clamped and is cut out.
When it actually used to control the sequential action of the executive components, the hydraulic pump starts, first 2YA power-on, the hydraulic cylinder left cavity into the oil, driving the piston to move to the right. When the system pressure rises, the pressure relay sends out an electrical signal to make 1YA energized, and the high-pressure oil enters the left cavity of the hydraulic cylinder, pushing the piston to move to the right. If 3YA is also energized, the piston of the hydraulic cylinder moves to the right quickly. If 3YA is powered off, the piston of the hydraulic cylinder moves slowly to the right, and its slow motion speed is regulated by the throttle valve.
When it is used again for unloading hydraulic pump, the pressure relay is not to control the hydraulic pump to stop rotating, but to control the two-position two-way solenoid valve, the hydraulic pump 5 output pressure oil flow back to the tank, so that it unloads.
Finally, when opening and closing the hydraulic pump, there are two hydraulic pumps, high pressure and small flow pumps, and low pressure and large flow pumps. When the piston drops rapidly, the two pump simultaneously outputs the pressure oil. When the hydraulic cylinder piston rod against the workpiece began to pressurize, the pressure relay in the pressure oil under the action of the action, touch the micro-switch, will normally close contact break, so that the hydraulic pump stop. During the processing, the speed of the hydraulic cylinder is slowed down and the power consumption is reduced.