In all excavator circles, there is a type of failure that can make the new teacher as helpless and helpless, that is, the excavator is normal when the car is cold or when the car is just started, but the posture of the excavator is weak and the speed gradually changes after the car is hot for a period of time. Go slower. So what is causing the fault, and how to clear the fault?
1. Hydraulic oil replacement and maintenance
Special reminder: For cars with relative ages, the hydraulic oil must be removed and replaced on time for cars that use the breaker for a long time. Many failures are caused by the hydraulic oil. Perhaps the hydraulic oil is thicker when the car is cold, so the cold car’s At that time, the total pressure and flow rate can be guaranteed. Once the hydraulic oil temperature rises to about 60 degrees, the posture starts to slow. Be sure to check the cleanliness of the hydraulic oil, return the oil filter, and the cleanliness of the suction filter. .
Expert tip: The common hydraulic oil for excavators is No. 46. The larger the model, the greater the viscosity. The lower the model, it is prone to high temperature. The higher the model, the increase in viscosity will harm the speed! Komatsu excavators now strongly recommend Doosan TO10 special transmission system oil.
2. Failure to control fuel pipe
Check the main pressure first when the hot car is slow. If the pressure is too low (at least 3.2MPA), then check whether the gear oil pump (Doosan vehicle self-pressure regulator) leaks, and whether the main filter element (filter) is caused by dirt. block. If the main pressure is insufficient, it is impossible to completely open the valve stem of the main pressure regulating valve during operation, which will cause very slow
3. Main pump failure
The main pump failure due to the slow hot car is one of the reasons. When checking and adjusting the total pressure and flow of the main pump, the response after adjustment is not large or the basis is not effective, then the main pump must be removed for inspection, the controller is worn, and the servo motor The wear of the plunger pump, the wear of the valve plate, the wear of the plunger pump and the engine block, and the wear of the swash plate, all of which lead to the low total flow of hot car pressure.
4. Failure of electromagnetic induction proportional pressure reducing valve
Another component that harms the pressure and total flow of the main pump is the electromagnetic induction proportional pressure reducing valve (the name of each well-known brand is different, and the function is basically the same). The electromagnetic induction proportional pressure reducing valve is used to obtain the data signal output from the CP U computer version. Flow, the dominant pressure is developed to account for the pressure, and then the remaining oil output of the pump is manipulated. If there is a problem, the total flow pressure of the pump will also be too low or stuck in a certain part and not adjusted.
5. Failure of the main pressure regulating valve
The internal leakage of the main pressure regulating valve is the root cause of the slow hot car. The key is that the maintenance is not timely, the hydraulic oil is not checked or replaced immediately, and the use of crushers is the root cause of the main pressure regulating valve. Improper adjustment and failure to immediately dismantle and change the hydraulic oil are all on the stem of the main pressure regulating valve. The main speed regulating valve and the oil hole speed regulating valve cause shock wear and eventually cause the internal leakage of the vehicle to be very slow.
The left and right points are all the key reasons for the slowness of the excavator after it warms up. Whether it is an overhaul master or an excavator boss, you must first find the direct cause of the fault and then "treat symptomatically."
