The reasons why the gear pump cannot pump oil

The failure of the gear pump in the hydraulic system during operation is usually due to the drop in oil pressure in the lubrication system, which sometimes fails to pump oil. The main reasons are as follows:

1) The direction of rotation is opposite to the specified direction;

2)Oil pump parts are severely worn;

3) The seal between the pump body and the pump cover of the oil pump is poor;

4) The oil suction pipeline is not tight, and the one-way valve is stuck;

5) The amount of oil in the oil tank is insufficient;

6) The oil suction filter is blocked.

The gear pump works with two gears meshing with each other and does not have high requirements for the medium. The general pressure is below 6MPa, and the flow rate is relatively large. A pair of rotary gears are installed in the pump body, one is active and the other is passive. The gear oil pump relies on the mutual meshing of the two gears to divide the entire working chamber in the pump into two independent parts. A is the suction cavity, B is the discharge cavity. During operation, the driving gear drives the driven gear to rotate, and when the gear is engaged to disengaged, a partial vacuum is formed on the suction side, and the liquid is sucked. The sucked liquid is filled with each tooth valley of the gear and brought to the discharge side. When the gears are meshed, the liquid is squeezed out to form high-pressure liquid and is discharged out of the pump through the pump discharge port.

In actual work, it should be handled differently according to the specific situation. During the inspection, special attention should be paid to the sealing of the oil suction pipe and the sealing between the gear pump body and the pump cover. If the suction end is not well sealed, air will leak into the inlet of the oil pump, causing the oil pump to evacuate, and naturally it will not be able to pump oil.

The old gear oil pump is generally not oiled because the gap is too large, that is, the gear and the gear, the gear and the pump body, and the gear and the end face are too worn. The above is a problem that occurs when the gear oil pump is used for a long time.