The reason for the reverse start of the four-column hydraulic press manufacturer's workbench

When the spool of the four-column hydraulic press manufacturer reaches the middle position, negative coverage is used, that is, the shoulder width of the spool platform is less than the sinking width of the valve body. At this time, the high-pressure oil and the cylinder meet, and the cylinder stops moving. Because the right chamber of the cylinder of the four-column hydraulic press is always connected with the high-pressure oil when it is made, the vacuum phenomenon in the cylinder cannot be caused by inertia, which is conducive to preventing the crawling phenomenon of gas mixed with the oil.

When the reversing valve spool of the four-column hydraulic press continues to move to the left, the oil discharged from the valve spool mainly flows back to the tank from the throttle valve, and the main oil circuit is reversed by the main valve spool until the oil circuit is blocked and the workbench begins to move in reverse. During this period, the valve table is in a stay state, and the throttle can be adjusted according to the length of the valve during the stay.

Although the main oil circuit of the four-column hydraulic press has been reversed, the cone on the main valve spool opens the oil return channel very small, and the cylinder starts slowly. Main spool continues to move to the left. At this time, the oil discharged from the end of the spool only flows out through the oil passage and throttle valve of the end face. In order not to go through the throttle valve, the spool is provided with a sink groove, so that the discharged oil can be discharged directly through the quick jump oil circuit. Changing the opening of the throttle valve can change the opening speed of the main valve national oil port controlled by the main spool cone, thus controlling the starting speed and stability of the four-column hydraulic press. When the main spool moves to open the end oil return port, the workbench speed reaches the corresponding value.

The reverse braking and reversing process of the four-column hydraulic press table is similar to the above process. The braking of the workbench is completed by the pilot valve distance braking and the main valve time valve braking. The length of the table residence time valve depends on the main valve, and the residence time valve can be controlled by adjusting the throttle valve of the four-column hydraulic press. The speed and stability of the reverse opening of the four-column hydraulic press table are also determined by the main valve, and the length of the valve can be adjusted by adjusting the throttle valve.