In the hydraulic system, when the three-position four-way reversing valve is in the neutral position, the oil path to the hydraulic cylinder is blocked, the two chambers of the hydraulic cylinder communicate with each other, and the oil path returns. The hydraulic system design is not perfect. Used single-arm hydraulic presses. The components are not matched. When the throttle channel is blocked, the system is leaking. The internal and external leakage of the system is serious. Excessive air enters the oil. The friction resistance changes. The hydraulic press will also cause the actuator to operate at low speed The speed is unstable and even crawling occurs.
In this way, part of the oil is poured back into the tank under the action of the potential energy hydraulic press. When the reversing valve is reversed, the hydraulic cylinder is fed with pressure oil in one cavity, and the other cavity causes the hydraulic cylinder to move forward due to the lack of backpressure, and the initial speed is unstable. In the double-rod hydraulic cylinder, due to the unequal leakage of the two chambers and the different frictional resistance of the reciprocating motion, the speed will also be unstable.
Careful observation will reveal that most four-column hydraulic press equipment is equipped with an ejector cylinder because many times the products we process require a component to eject the product from the mold, this time the ejector cylinder needs to be installed. The function of the ejection cylinder is very simple. In general, it is used for demoulding, and the workpiece is ejected from the concave mold.
The working process of ejecting the cylinder of the four-column hydraulic machine is the ejection of the workpiece. The specific implementation is that when the main cylinder returns to the stop motion, press the eject button, the corresponding electromagnet is energized, and the cartridge valve is opened, and the hydraulic oil is inserted through the valve. The valve enters the lower cavity of the ejection cylinder, the oil in the upper cavity flows back to the oil tank through the valve, and the workpiece is ejected.
The second is to eject the ejector cylinder. Press the ejection button first, the electromagnet loses power, and several other electromagnets are energized. The cartridge valve opens, the hydraulic oil enters the upper chamber of the ejector cylinder through the valve, and the lower chamber oil flows back through the valve Fuel tank, back out of the cylinder. After these steps are completed, the next step is started, and then a circulation system is formed to maintain the continuous movement of the four-column hydraulic press.