1. The engine speed drops
The first thing to test is the output power of the engine itself. If the engine output power is lower than the rated power, the cause of the problem may be poor fuel quality, low fuel pressure, incorrect valve clearance, a cylinder of the engine is not operating, and the injection timing is wrong. The set value of the fuel quantity is incorrect, the air intake system leaks, the brake and its control rod are defective, and the turbocharger deposits carbon. If the engine output power is normal, you need to check whether the flow of the hydraulic pump does not match the output power of the engine. The speed of the hydraulic loader is inversely proportional to the load during operation, that is, the product of the flow rate and the output pressure of the pump is an invariant, and the output power of the pump is stable or approximately stable. If there is something wrong with the pump control system, the load optimization and matching state of the engine, pump and valve in different working conditions cannot be completed, and the loader will not work normally. Such problems must start with the electrical system, then check the hydraulic system, and finally the mechanical transmission system.
2. The operation speed becomes slow
The main reason for the slower operation of the loader is the wear of all parts of the machine, which results in the decrease of engine power and the leakage of the hydraulic system. The hydraulic pump of the loader is a plunger variable pump. After working for a time, the internal hydraulic components of the pump (cylinder, plunger, valve plate, nine-hole plate, turtle back, etc.) will inevitably undergo excessive wear and will cause internal leakage. , The data of each parameter is not coordinated, resulting in insufficient flow rate, high oil temperature, and slow operation speed. At this time, the whole machine needs to be overhauled to repair and replace the parts with excessive wear.
But if the loader that is not working for a long time suddenly slows down, you need to check the following aspects. First check whether the circuit fuse is open or short circuit, then check whether the pilot pressure is normal, and then see if the servo control valve-servo piston is stuck and whether the distributor confluence is defective, etc., finally disassemble the hydraulic pump for data measurement to confirm the problem of the excavator .
3. Common faults during excavation
Some common problems that often occur in the construction industry of the loader, such as: excavator walking deviation, the reason may be that the distribution oil seal (also called the center reverse joint oil seal) is damaged; the flow rate of the two hydraulic pumps is different; one side There is a problem with the travel motor. The rapid discharge of the hydraulic cylinder may be due to the safety relief valve being closed tightly, or the cylinder oil seal being severely damaged, etc.
4. Weak loader
Discovery of weakness is one of the typical problems of loader. There are two kinds of cases about powerless excavation: one is powerless excavation, the engine does not hold back the car, and the load is very light; the second is powerless excavation, when the boom or stick is extended, the engine is severely held back, or even shuts down .
①Discover the weak but the engine does not hold back the car. The magnitude of the excavation force is determined by the output pressure of the main pump. Whether the engine is held back depends on the relationship between the absorption torque of the oil pump and the engine output torque. If the engine does not hold back, the oil pump absorbs less torque and the engine load is light. If the operating speed of the loader is not significantly abnormal, you should check 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 set value of the overload relief valve of the hydraulic circuit of the organization is incorrect, which causes the organization to overflow prematurely and the operation is weak. You can adjust the machine by rolling the adjustment screw.
②Exploration of weakness, engine hold back. The engine holding vehicle indicates that the absorption torque of the oil pump is greater than the output torque of the engine, causing the engine to be overloaded. This problem should first check whether the engine speed sensing system is normal, and the checking method is similar to the engine checking method described above. Through the above detailed inspection and troubleshooting, the engine speed sensing system recovers its normal function, the engine holding phenomenon disappears, and the excavation power will recover normally.
5. Daily maintenance of the loader In order to avoid the fault of the loader, it is necessary to pay great attention to the maintenance of the loader during the daily use.
Daily maintenance includes viewing, cleaning or replacing the air filter element; cleaning the interior of the cooling system; viewing and tightening the track shoe bolts; viewing and adjusting the track back tension; viewing the air intake heater; replacing bucket teeth; adjusting bucket clearance; viewing the front window Cleaning fluid level; viewing, conditioning air conditioning; cleaning the floor in the cab; replacing the crusher filter (optional accessory). When cleaning the inside of the cooling system, after the engine is sufficiently cooled, slowly unscrew the water inlet cover, release the internal pressure of the water tank, and then drain the water; do not perform cleaning operations when the engine is operating, the fan rotating at high speed will pose a risk; when cleaning or replacing the cooling When the liquid is filled, the machine should be parked on a level ground.
At the same time, before starting the engine, you need to check the height of the liquid level of the coolant (add water); check the engine oil level, add oil; check the fuel oil level (plus fuel); check the hydraulic oil level (plus hydraulic oil); check the air filter Check whether the wire is blocked; check whether the horn is normal; check the lubrication of the bucket; check the water and sediment in the oil-water separator.
There are many problems encountered by the loader in daily operations. Here are just a few common types of maintenance methods. In order to reduce the incidence of problems, the daily maintenance of the loader is very important.
