What is the working condition of the slider on the four-column hydraulic press?

What is the working condition of the slider on the four-column hydraulic press? Today, let's take a look at what the operation of the slider on the four-column hydraulic press is like

First, fast down: the electromagnet is energized, the four-column hydraulic press pilot valve and the upper cylinder reversing valve are connected to the left of the system, and the hydraulic check valve is opened. The upper slider drops rapidly under the self-weight effect. Because the flow rate of the hydraulic pump (unit: cubic meters per second) is small, the oil in the oil storage tank at the top of the hydraulic press also flows into the upper chamber of the upper hydraulic cylinder through the hydraulic control single valve.

Second, slow pressure: when the slider touches the workpiece on the four-column hydraulic press, the pressure on the upper chamber of the hydraulic cylinder rises at this moment, the hydraulic control check valve is actively closed, the variable pump supplies oil, and the slow pressure is completed, and the oil activity is the same as when the fast speed goes down.

When the upper four-column hydraulic cylinder chamber oil pressure reaches the setting value, the pressure relay action, on the one hand, the electromagnet power off, on the other hand, the time relay action, to complete the rolling. When maintaining pressure, there is no oil activity in the system except that the hydraulic pump is unloaded at a lower pressure.

Four, quick back: the four-column hydraulic press is completed, the time relay is operated, the electromagnet is energized, the pilot valve is connected to the system on the right, the pressure relief valve makes the upper cylinder reversing valve also access the system from the right, and the quick back start at this moment. At this time, the hydraulic control check valve is opened. When the level of the oil storage tank exceeds the preset position, the excess oil flows back to the main tank through the overflow pipe.

5. In-situ stop: When the slider on the four-column hydraulic press rises to the stop block hitting the stroke switch, the electromagnet is powered off, and the pilot valve and the upper cylinder reversing valve are in the middle position, the in-situ stop stage begins. At this time, the upper slide block stops moving, the hydraulic pump is unloaded at low pressure, and the oil activity in the system is the same as that during the calender. What should be noted here is the effect of the pressure relief valve and its operating principle. The pressure relief valve of the four-column hydraulic press is set up in order to avoid the rapid change of the pressure holding condition to the rapid return condition, which causes the pressure shock in the system and makes the upper slider action unstable. Its primary function is to make the upper cavity of the hydraulic cylinder release pressure, and the pressure oil can pass into the lower cavity of the cylinder.