How to repair the failure of the oil pump in the hydraulic system of a small excavator

How to repair the failure of the oil pump in the hydraulic system of a small excavator

2020-11-12 10:57:54  edit:xiaoli

How to repair oil pump failure of hydraulic system of small excavator

We usually call this phenomenon "work crawling." Repairing the crawling phenomenon of small excavators will not only destroy the stability of the hydraulic system, but sometimes even cause vibration and noise. Therefore, air must be prevented from entering the hydraulic system.

How to repair the failure of the oil pump in the hydraulic system of a small excavator

(1) The suction pipe of the pump and the sealed end of the pump shaft end are lower than atmospheric pressure, so be careful not to leak.

(2) Prevent the air from returning to the oil pipe, and the oil return pipe should not be exposed on the surface of the oil tank.

(3) If the system has entered air, the leakage should be detected in time to eliminate the leakage and exhaust the air entering the system.

(4) After adding new oil, continuously operate the working device to make it rise, fall and reverse to discharge the air in the system. When excavating, turning, shoveling, lifting, etc., the action must be smooth and accurate. The joystick should be retracted in time to avoid excessively fast, so as to prevent the hydraulic cylinder, hydraulic motor and other actuators from suddenly opening or closing. When the oil outlet is opened, a pressure shock is generated, which causes accelerated damage to the oil seals of various parts, foaming of the high-pressure hose, and loosening of pipe joints and leakage.

Because the instantaneous opening is too large, the safety valve may even be stuck, causing internal leakage, causing operating failures, reducing work efficiency and shortening service life. When repairing the hydraulic system of an excavator, some abnormalities often occur. Strict daily inspections and maintenance are of great significance for the timely detection and elimination of minor faults and the prevention of major accidents. Therefore, attention should be paid to and strengthened daily inspection and maintenance.

(1) Before the hydraulic system works, carefully check whether the fasteners and pipe joints are loose and whether the pipeline is deformed or damaged.

(2) Before the first operation of the hydraulic pump, the pump should be filled with oil to prevent damage to the hydraulic pump due to air operation.

(3) When the hydraulic pump starts to run, it can run continuously (especially in cold areas) to see if the operation is flexible. Before entering the operation, ensure that the operation is normal and there is no abnormal noise.

(4) If the working pressure of the distribution valve of the hydraulic system of the working device exceeds or falls below the specified value. Should be adjusted.

(5) After the hydraulic system enters a stable working state, in addition to paying attention to oil temperature, pressure, and sound, attention should also be paid to the working state of hydraulic cylinders, hydraulic motors, reversing valves, and safety valves. And other components. And the oil leakage and vibration of the entire system.

"Leakage" Phenomenon of Small Excavator and Its Cause Analysis

When the joint is leaking and the hose is working, the leaking parts can be distinguished by static and dynamic. If water accumulates in the pipeline, it is easy to freeze and block the air path, so it should be cleaned up in time.

Airtightly handle component defects

The oil-water separator is blocked and damaged, and the movable parts of the drain valve fail. Be sure to clean the filter element and remove oil and other impurities from the drain valve. The oil always does not drip, there is water at the bottom of the oil cup, and the seal of the oil cup is damaged. Check whether the airflow at the air inlet is lower than the mist flow and if there is any leakage.

Cylinder defects:

(1) Remove condensate and impurities in the cylinder in time.

(2) Insufficient output power of the cylinder and unstable operation are often caused by the stuck piston or piston rod, poor lubrication, insufficient air supply, or condensation and impurities in the cylinder. The middle position of the piston rod should be adjusted. Check the reliability of oil well operations; whether the gas supply pipeline is blocked.

(3) The cushioning effect of the cylinder is slow or cannot be reversed normally.

This is a way to repair the failure of the hydraulic system of a small excavator. Hope it helps you.

Copyrigh: MINI Excavators&Crawler Hydraulic Excavator