What are the reasons for the abnormal pressure of the hydraulic cylinder in the 500-ton four-column hydraulic press?
- Reasons related to the hydraulic pump and hydraulic motor
- The hydraulic pump and motor have been used for a long time, the internal wear is severe, the leakage is large, and the volumetric efficiency is low, causing the output flow of the hydraulic pump to be insufficient and the system pressure is low.
- The engine speed is too low, the efficiency is insufficient, causing the system flow to be insufficient, and the hydraulic system pressure is low.
- The position of the hydraulic pump directional control device is wrong or the assembly is incorrect, the pump does not work, and the system has no pressure.
- Reasons for the hydraulic control valve
- During the working process, if it is found that the pressure cannot go up or down, it is likely that the reversing valve has failed, causing the system to continuously unload or maintain high pressure.
- The damping hole of the relief valve is blocked, there are burrs on the main spool, and there are impurities between the spool and the valve hole and the gap, which may cause the main spool to be stuck in the fully open position. The hydraulic oil output by the hydraulic pump directly returns to the oil tank through the relief valve, and the pressure oil circuit and the return oil circuit are short-circuited, causing the system to have no pressure; if the burrs or impurities jam the main spool in the closed position, the system pressure may continue to be very high and cannot come down; When the spool of the relief valve or reversing valve is stuck, the spool action is not flexible, and the actuator will have the phenomenon of sometimes having action and sometimes no action, and when checking the system pressure, it will show that the pressure is unstable.
- For systems with check valves, if the direction of the check valve is reversed, it may also cause the system pressure to not rise.
- Internal and external leakage of the system, such as serious leakage between the spool and the valve body hole, will also cause the system pressure to not rise.
- Other reasons
- The low oil level in the hydraulic oil tank, the thin oil suction pipe, and the blockage of the oil suction filter by impurities will cause the hydraulic pump to have a large oil suction resistance, causing the system flow to be insufficient and the pressure to be low.
- In addition, the return pipe is on the liquid surface, the oil suction pipe is not well sealed and leaks, etc., which can easily cause air to mix into the hydraulic system, causing the system pressure to be unstable.
