Analysis of Hydraulic Cylinder Leakage Faults

During the operation of excavators, hydraulic cylinder leakage is a common issue that causes considerable inconvenience. As an essential component of excavators, hydraulic cylinders often face leakage problems, both externally and internally. Let's explore the reasons behind hydraulic cylinder leakage and what precautions can be taken to prevent it.

External Leakage Causes:

  1. Damage to the seal between the piston rod and its mating surface, often due to scratches on the cylinder caused by abrasion or aging.
  2. Seal damage between the piston rod and cylinder sleeve mating surface, typically resulting from prolonged use or excessive force during assembly, exacerbated by cost-saving designs from manufacturers.
  3. Cracks in hydraulic lines connected to the cylinder, leading to leakage.
  4. Defects on the cylinder body or end cap causing oil leakage.
  5. Damage to the piston rod, such as scratches or pits.
  6. Oil degradation causing abnormal temperature increases, accelerating seal aging.
  7. Oil leakage due to exceeding the pressure range of the cylinder.

Internal Leakage Causes:

  1. Severe wear of the wear ring on the piston, leading to friction between the piston and cylinder sleeve, ultimately damaging the seals.
  2. Long-term seal failure, particularly the piston seals (such as U, V, or Y rings) aging over time.
  3. Contaminated hydraulic oil, where foreign particles enter the cylinder, causing seal wear, typically metallic debris or other contaminants.

Apart from seal aging, other causes of hydraulic cylinder leakage can be avoided with proper maintenance. Now, let's discuss some key considerations for using hydraulic cylinders:

Precautions for Hydraulic Cylinder Usage:

  1. Protect the piston rod surface from damage to prevent harm to seals. Regularly clean dust and debris from the cylinder and exposed piston rod to prevent entry into the cylinder.
  2. Regularly inspect and tighten all connections like threads and bolts to prevent leakage due to loosening.
  3. Lubricate joints regularly to prevent corrosion or abnormal wear in the absence of oil, especially in areas prone to rust.
  4. Regularly change hydraulic oil and clean system filters to maintain oil cleanliness, crucial for extending cylinder lifespan.
  5. Control system temperature to prevent seal damage from overheating, as high temperatures can cause permanent seal deformation.
  6. Perform several full extension and retraction cycles before starting work to purge air from the system and preheat components, avoiding air or water presence that could lead to internal cylinder leakage.
  7. After completing work, ensure the boom, arm, and bucket are in a neutral position to allow hydraulic oil to flow back to the tank, relieving pressure on the cylinder and preventing seal damage.

In summary, hydraulic systems are vital for excavators, and addressing any issues promptly while maintaining proper care can minimize downtime and maximize performance. Regular inspections and maintenance are essential for preserving your equipment.

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