Excavator is a machine composed of thousands of parts. It is inevitable that some faults will occur in the process of use, especially those excavators that have been used for a certain period of time. The most common walking faults are engine holding, walking card, walking frustration, slow walking speed and so on.
1. The engine is choked when walking
1) Hydraulic motor reducer failure
Hydraulic motor is a kind of motor with high speed and low torque, which can not directly drive the excavator. Generally, planetary gear set is used to decelerate the hydraulic motor and improve the torque. When the reducer fails, the resistance of the reducer itself is too large, resulting in too high load of the hydraulic motor and rising pressure of the hydraulic circuit, resulting in engine suffocation.
2) Track too tight
The tightness of the crawler of the excavator is adjustable. Through the stroke adjustment of the tensioning oil cylinder, when the crawler is too tight, the resistance of the hydraulic motor is too large, which is easy to cause suffocation.
3) The track is frozen in winter
In winter, the temperature in some areas is extremely low. The crawler of the excavator is stained with water and mud after working the previous day. When starting the next day, the water will freeze the crawler, resulting in excessive load of the hydraulic motor and pressure rise of the hydraulic circuit, resulting in engine suffocation.
2. Traveling card
1) Pilot valve stem not in place
When the pilot valve stem is not in place, the pilot system cannot produce stable secondary pilot pressure oil, resulting in the unstable position of the valve core of the main control valve and the travel card.
2) Mechanical failure of reducer
In case of mechanical failure of the internal gear set of the reducer, the reducer will work abnormally, unable to output stable speed and torque, resulting in travel card.
3) Traveling system fault
Travel balance valve, travel safety valve, travel speed switching valve, travel speed switching oil cylinder, travel brake oil cylinder, throttle valve and travel motor may cause travel jam.
3. Walking frustration
1) Main pump variable unstable
The pump control system of the excavator main pump can collect the outlet hydraulic oil pressure of the main pump through the central controller, output the electrical signal after analysis and calculation, and change the swashplate angle of the main pump with the cooperation of control valve, pressure reducing valve, regulating cylinder and other elements, so as to achieve the purpose of adjusting the displacement and output flow of the main pump.
When the pump control system fails, it is easy to cause the output flow of the main pump to be unstable, resulting in a sense of frustration when operating the excavator.
2. Failure of main valve and secondary valve of safety relief valve
Generally speaking, the maximum pressure of the hydraulic system of the excavator is determined by the overflow valve. When the overflow valve fails, such as fatigue failure of the overflow valve spring or stuck valve core, it is easy to cause the set value of the overflow pressure of the overflow valve to change, and the pressure in the hydraulic circuit is unstable, resulting in a sense of frustration when operating the excavator.
4. Slow walking speed
1) High low speed conversion fault of traveling system
When the high-speed and low-speed conversion of the traveling system of the excavator fails, it may not be able to switch to the rabbit gear, resulting in the excavator always walking in the tortoise gear and slow walking speed.
2) Abnormal pump control system and insufficient flow
The traveling speed of the excavator is determined by the speed of the hydraulic motor. When the pump control system of the main pump is abnormal, the output flow of the main pump is unstable. When the swashplate angle of the main pump is too small, the output flow of the main pump is low, which will lead to the slow traveling speed of the excavator.
3) Abnormal pilot system
The secondary pressure oil of the pilot system is output by the proportional control valve. When the traveling operation valve in the excavator cab leaks or is stuck, it will lead to insufficient pressure of the pilot secondary pressure oil, unable to push the valve core of the main control valve in place, and the flow of the hydraulic circuit of the traveling system decreases, resulting in slow traveling speed of the excavator.
