During the normal construction process of the excavator, if the temperature of the hydraulic oil rises too fast and the temperature is too high, the hazard is very large, on the one hand, it will increase the internal leakage of the hydraulic system, and the operating speed will be significantly reduced, which will damage the hydraulic precision components .
Failure analysis:
The first case:
① The hydraulic system design is unreasonable. Although the probability of this reason is relatively small, it cannot be ruled out. For example, the diameter of some of the hydraulic lines is too small, and the oil flow at the pipe joints is not smooth. The bending radius of the tube is too small.
② The opening of the valve hole is too small. If it is determined to be the cause, you must switch to a valve with a larger opening according to your needs.
③ The opening pressure of safety valve, speed limit valve, pressure reducing valve, etc. is too high, and the opening pressure of the above valves should be readjusted according to the specified value.
The second situation:
Check whether the cooling fan is operating normally. If the fan speed is abnormal, for a stand-alone cooling system, it may be caused by the following three reasons:
① The fan motor is seriously worn. This reason is very common. Once the wear is severe, the internal leakage must be large. The fan motor should be replaced.
② The gear oil pump supplying the pressure oil from the fan motor is severely worn, causing a large amount of internal leakage; the gear pump should be replaced.
③If the fan motor speed is normal, the temperature rise of the hydraulic oil is still very high, you should check the cooler surface for excessive dirt, which affects the cooling effect. If it is, the dirt should be removed. If the cooler surface is clean, the distance between the fan blade and the cooler should be adjusted to ensure the cooling effect.
④ For excavators that are not independent cooling systems, the owner should also check whether the fan belt slips. If the fan belt slips, adjust the fan belt tension or replace it with a new belt.
The third case:
After troubleshooting the cooling system, if the hydraulic oil temperature is still very high, the maintenance personnel should carefully listen to the hydraulic system for abnormal noise. If there is noise, measures should be taken against the source of the noise to eliminate the fault.
The fourth situation:
The main safety valve or secondary overload valve is opened too frequently, and the temperature of the hydraulic oil will rise too fast and too high. Correct operation according to the following method can overcome the frequent opening of the main safety valve or secondary overload valve:
①Single action should not be too much, as many compound actions as possible should be done when digging.
② When digging, try not to touch or stop the stopper as much as possible to reduce or avoid the opening of the relief valve of the main safety valve or secondary overload valve.
The fifth situation:
Using unqualified hydraulic oil will also cause the oil temperature to be too high. Everyone can check whether the hydraulic oil in the machine has the following conditions, if it is, you must replace the oil in time
①Hydraulic oil contains water or impurities;
②Viscosity of hydraulic oil is too large;
③ The viscosity of hydraulic oil is too small.
