4. The long arm excavators is weak

Weak digging is one of the typical failures of long arm excavators. There are two situations for digging weakness: one is digging weakness, the engine does not hold the car, and the load is very light; the second is digging weakness, when the boom or stick is extended to the end, the engine is severely suffocated or even stalled .

①The excavation is weak but the engine does not hold back the car. The size of the digging force is determined by the output pressure of the main pump, and whether the engine is holding back depends on the relationship between the absorption torque of the oil pump and the output torque of the engine. If the engine does not hold back the car, it means that the oil pump absorbs less torque and the engine load is light. If there is no obvious abnormality in the working speed of the excavator, focus on checking the maximum output pressure of the main pump, that is, the system overflow pressure. If the measured value of the overflow pressure is lower than the specified value, it indicates that the setting value of the overload relief valve of the hydraulic circuit of the mechanism is incorrect, causing the mechanism to overflow prematurely and work weakly. You can adjust the machine by turning the adjustment screw.

②The excavation is weak and the engine is holding back the car. The engine holding the car indicates that the absorption torque of the oil pump is greater than the output torque of the engine, which causes the engine to be overloaded. This kind of failure should first check whether the engine speed sensing system is normal. The inspection method is similar to the engine inspection method described above. After the above detailed inspection and troubleshooting, the engine speed sensing system returns to its normal function, the engine holding back phenomenon disappears, and the digging force will return to normal.

5. Daily maintenance of the excavator

In order to prevent the failure of the long arm excavators, it is necessary to pay great attention to the maintenance of the excavator during daily use. Daily maintenance includes checking, cleaning or replacing the air filter element; cleaning the inside of the cooling system; checking and tightening the track shoe bolts; checking and adjusting the track back tension; checking the air inlet heater; replacing the bucket teeth; adjusting the bucket gap; checking the front window Clean the liquid level; check and adjust the air conditioner; clean the floor in the cab; replace the filter element of the breaker (optional).

When cleaning the inside of the cooling system, after the engine is sufficiently cooled, slowly loosen the water inlet cap to release the internal pressure of the water tank, and then discharge the water; do not clean when the engine is working, the high-speed rotating fan will cause danger; when cleaning or replacing the cooling When liquid, the machine should be parked on a level ground.

At the same time, you need to check the height of the coolant level (add water) before starting the engine; check the engine oil level, add oil; check the fuel level (add fuel); check the hydraulic oil level (add hydraulic oil); check the air filter element Check whether it is blocked; check the wire; check whether the horn is normal; check the lubrication of the bucket; check the water and sediment in the oil-water separator.