Excavator hydraulic pump oil supply is insufficient, the pressure can not rise how to do?
The hydraulic pump is the energy device of the excavator hydraulic system, which converts the mechanical energy of the motor into hydraulic energy and outputs flow and pressure, and occupies a very important position in the hydraulic system. If the hydraulic pump fails, it will affect the normal work of the entire hydraulic system. This article mainly introduces the excavator hydraulic pump failure causes and troubleshooting methods.
Pressure does not go up
Reason 1: the pump is not on the oil or insufficient flow.
Remedy: fill the pump with working oil.
Reason 2: relief valve adjustment pressure is too low or failure.
Remedy: Re-adjust the pressure of the relief valve or repair the relief valve.
Cause 3: Leakage in the system.
Remedy: Check the system, repair the leakage point.
Reason 4: The pump cover screws are loosened due to the vibration of the oil pump working for a long time.
Remedy: Tighten the screws properly.
Reason 5: Air leakage in the suction pipe.
Elimination method: check the connections, and be sealed and tightened.
Reason 6: Insufficient oil suction.
Remedy: Fill the pump with working oil.
Reason 7: Improper adjustment of variable pump pressure.
Remedy: Re-adjust to the required pressure.
Hydraulic pump oil supply is insufficient
Troubleshooting: External air enters the working chamber of the piston pump resulting in reduced displacement.
Failure Analysis: Due to the harsh working environment of the excavator, it is very easy for the piston pump to rupture the suction pipe or the suction port is not sealed properly, which leads to the pump sucking in air. Plunger pump in the work, if the oil in the plunger working chamber into the air, then when the plunger is in the position of the pressure port, the plunger will pressurize the oil and air in the chamber.
When the plunger moves to the bottom of the cylinder hole, there will always be part of the remaining volume at the bottom, i.e., part of the pressurized oil is retained in the remaining volume of the cavity. When the plunger continues to run to the suction port position, with the increase of the cavity volume, the internal oil pressure is reduced, the air trapped in the remaining volume is expanded, so that part of the working cavity will be occupied by this part of the air, so that the actual suction volume of the piston pump is reduced. When the air into the fluid reaches a certain amount, it will cause the system to supply insufficient oil or even no oil supply. Furthermore, if the hydraulic oil can not flow into the suction port in time, the pump suction will produce air pockets, thus causing premature damage to the plunger seal and plunger cylinder wall cavitation and other failure phenomena. Therefore, measures must be taken to reduce or eliminate air into the hydraulic system.
Elimination methods:
1. Ensure that there is no leakage at all inlet line connections. In order to ensure that they are well sealed, all pipe joints should be tightened; for piston pumps, they must have a tighter sealing device.
2. Prevent the suction hose from rupturing or sucking flat. Try to control the flow rate of the liquid at the suction port to prevent the pressure at each point of the suction line from being lower than atmospheric pressure and forming a vacuum, resulting in rubber hose leakage, suction flattening and air intrusion.
3. Control the height of the oil tank oil level. Normally the lowest level of the oil tank and the suction port of the vertical distance should be less than 0.5m; if the system allows, the height of the oil level in the tank should be higher than the suction port of the pump, and so that the end of the hydraulic system back to the oil pipe is often in the oil level below, so as to avoid the production of air bubbles.
4. If there is a large number of air bubbles in the tank, should be excluded in a timely manner. If there is a considerable amount of air in the fluid, the piston pump outlet pipe fitting can be loosened to discharge the pump air.