Failure reason of hydraulic system losing pressure (1)       

In the actual work, because the maintenance personnel of hydraulic system hydraulic medium and the mechanism of work is not enough understanding, because misuse and misuse of mechanical or parts damage caused by many examples. The causes of the weak action of the hydraulic machinery are usually caused by the system loss of pressure, and there are usually 3 reasons for the system loss of pressure:

1, a relief valve opens to reset

Hydraulic circuit when the load is overweight, the spill valve to protect the system security. Overflow valve spool action, if the medium contains impurities (such as damaged rubber seals residue, etc.), or because open too big, too fierce and the valve can not reset the card, will make the entire oil system unloading. In this case, the mechanical actuator will suddenly appear unable to act (but can still hear the sound of the pump rotation) fault phenomenon. At this time, should remove the overflow valve spool will reset after cleaning, put it back. After the overflow valve is installed in the oil circuit, the load of 1.25~1.35 times of the rated load of the machine can be adjusted, and its opening pressure can be reset again.

Fault 2, hydraulic pump

Should pay special attention to the connection of hydraulic pump fault. If the machine appears in a short time no load (or light load), most of the mechanical connection of the hydraulic pump is out of order, at this time can hear the hydraulic pump drive abnormal sound. In this regard, the bolt or key should be checked at the junction to see whether it has been loose.

If the hydraulic system failure has long time pressure drop, but still can work under pressure, it is likely to be insufficient oil pressure hydraulic pump itself. When testing the hydraulic pump, it should be noted that because the pressure of the system is established, there are two conditions of the load and the pressure source, so the load should be applied to the oil circuit when judging the oil supply pressure. In the field work, some maintenance engineers take the hydraulic pump out of the oil pipe or the implementation of components into the oil pipe, according to the hydraulic pump rotation when the oil pipe to judge the oil supply pressure of the hydraulic pump, this method is unreliable. The correct test method is to connect the pressure gauge on the system, remove the unloading fault inside the oil circuit, and then apply the appropriate load to the system to test the oil pressure.