The so-called single-arm hydraulic press maintenance failure mainly refers to the situation that the maintenance pressure of the oil cylinder cannot be maintained during the time that the equipment needs to maintain pressure, and gradually declines. The main reason for not maintaining pressure is the leakage of the cylinder and control valve. The main way to solve the failure of not maintaining pressure is to reduce leakage as much as possible, and then leakage will exist for hydraulic press equipment, and the pressure will inevitably drop slowly. When the pressure holding time is required for a long time and the pressure remains stable, the oil replenishment method can be used to solve the problem.
1. Internal leakage and external leakage of the oil cylinder, resulting in no pressure maintenance.
The internal leakage between the two cavities of the oil cylinder mainly depends on the reliability of the piston sealing device. Usually, the reliability is divided into soft sealing ring, hard cast iron piston sealing and gap sealing from large to small.
Solution: Improve the manufacturing accuracy and matching accuracy of the cylinder, piston and piston rod, so as to reduce the failure of poor pressure retention caused by internal leakage and external leakage.
2. The leakage of various hydraulic valves, especially the leakage of the reversing valve close to the oil cylinder, is also an important reason for whether the pressure is maintained.
The leakage of hydraulic valve mainly depends on the manufacturing precision and structural form of the valve. Therefore, the pressure maintaining effect of the poppet valve is much better than that of the sliding valve type with positive cover. In addition, it is necessary to improve the assembly accuracy and processing accuracy of the valve. Even the valve with a cone seal should pay attention to the accuracy of the cylindrical fitting part and the reliability of the cone seal.
In the process of maintaining the pressure of the single-arm hydraulic press, it is possible to continuously supplement the leakage of the hydraulic system. Although this method is very troublesome, it is indeed a practical method when the pressure needs to be maintained for a long time. This method can keep the oil cylinder pressure remains unchanged. When replenishing oil, a small pump can be used to replenish oil, or an accumulator can be used to replenish oil. In addition, some methods in the pump source circuit can also be used to maintain pressure.
