Excavator Weakness: A Translation and Explanation
The term “excavator weakness”, also known as “excavator has no power” or “excavator has no strength” , refers to a common excavator malfunction where the machine exhibits slow and sluggish movements during operation.
Classification of Excavator Weakness
1. Excavator Work Weakness: Lack of power during operation (cold start weakness / hot start weakness).
2. Excavator Travel Weakness: Weakness in movement (left/right travel weakness or weakness on both sides).
3. Excavator Swing (Rotation) Weakness: Lack of power during rotation.
4. Boom/Arm Lifting Weakness: Weakness in raising the boom or arm.
5. Bucket/Stick Extension/Retracting Weakness: Lack of power in extending or retracting the bucket or stick.
Causes of Excavator Weakness
Detailed Explanation of Excavator Weakness Symptoms:
1.Excavator Work Weakness: This can be further divided into two categories: cold start weakness and hot start weakness.
-Cold Start Weakness: Common causes include:
– Faulty main relief valve
– Unloading valve issues
– Hydraulic pump malfunctions
– PC-EPC valve failures
– Damaged engine speed sensor
– Worn oil seals in the distributor
– Poor sealing of control valves
– Pilot valve failures
– Blockages in the regulating valve, etc.
-Hot Start Weakness: In addition to the causes mentioned above, hot start weakness can also result from:
– Dirty hydraulic oil used in the excavator, leading to contamination of the hydraulic system.
– Internal leakage in the hydraulic system, causing the pressure and flow values of the hydraulic pump’s valve group to fall below the specified requirements.
– Wear on the main pump, which can occur after the excavator has been operating for a while. As the hydraulic oil temperature rises, increased leakage can result in insufficient pressure, leading to a lack of power during operation.
Common Causes of Excavator Travel Weakness
1.Long-term Overloading of the Excavator Engine: Prolonged operation under excessive load can lead to insufficient power and result in weakness.
2.Wear or Damage to the PC Valve: Deterioration of the PC valve can affect performance.
3.Incorrect Overflow Pressure in the Travel Motor: Issues with the overflow pressure of the travel motor or wear in the overflow valve can lead to weakness.
4.Adjustment Defects in the Main Overflow Valve: Improper adjustments can cause performance issues.
5.Inconsistent Travel Pressure Values Between Left and Right Travel Motors: Discrepancies in pressure values can lead to uneven movement and weakness.
Common Causes of Excavator Swing (Rotation) Weakness
1. Weakness During Swing Operation: This issue can arise from two main factors: electrical faults and hydraulic faults in the excavator.
2. If Caused by Electrical Faults: A detailed inspection of the excavator’s wiring and the voltage and resistance values at various connections is necessary.
3. If Caused by Hydraulic Faults: Common causes include:
– Wear of internal components in the swing pump
– Wear of the oil distribution plate (flow distribution plate)
– Failure of the pump control valve
– High or low pressure values in the left and right swing circuits
– Internal pressure relief in the swing pump
– Seal failure in the swing motor, leading to oil leakage
– Improper adjustment of the overflow valve, resulting in overload of the swing motor.
Common Causes of Weakness in Boom (Arm) Lifting
1.Blockage in the Oil Supply Line: There may be a blockage in the oil supply line, leading to insufficient oil flow; the oil pump’s suction filter may be clogged, preventing the pump from drawing oil.
2.Internal Leakage in the Boom Cylinder: There could be internal leakage in the boom (arm) cylinder.
3.Internal Leakage in the Hydraulic Cylinder: The hydraulic cylinder may also have internal leakage.
4.Insufficient Oil Level in the Tank: The oil level in the tank may be too low.
5.Sticking or Damage to the Holding Valve: The holding valve may be stuck or damaged.
6.Clogged or Faulty Overflow Valve: The overflow valve may be blocked or malfunctioning.
Common Causes of Weakness in Bucket (Stick) Extension/Retracting
1. Stuck or Leaking Multi-way Valve (Main Control Valve) System: The multi-way valve system may be jammed or leaking oil.
2. Wear of the Bucket Stick Oil Line Valve Core: The valve core in the oil line for the stick may be worn.
3. Wear or Damage to the Bucket (Stick) Cylinder Assembly: The cylinder assembly for the bucket (stick) may be worn or damaged.
4. Sticking or Wear of the Bucket (Stick) Slide Valve Core: The slide valve core for the bucket (stick) may be stuck or worn.
5. Weak Spring Force in the Regeneration Circuit Valve or Check Valve: The spring force in the regeneration circuit valve or check valve may be too weak.
