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What Are the Causes of Oil Leaks in Industrial Robots?

Robot oil leaks are usually not caused by a single factor, but rather by the combined effect of multiple factors. Common causes can be categorized as follows; you can use these symptoms to conduct a preliminary investigation.

1. Causes of oil leaks in industrial robots

    1.1 Aging or damage to the seals (most common cause)

• Phenomenon: Slow oil seepage at joints and oil pipe connections, with the oil stains spreading outwards.
• Specific reasons:
  • Natural aging: Rubber parts such as O-rings and oil seals harden and crack under long-term high temperature and chemical corrosion.
  • Mechanical wear: Wear on the journal or housing creates grooves, which accelerates the damage to the oil seal lip.
  • Improper installation: During maintenance, the seal may be twisted, scratched, or dry friction may occur due to lack of lubricant.

    1.2 Mechanical structural damage

• Phenomenon: Sudden large-scale oil leakage, accompanied by abnormal noises or vibrations.
• Specific reasons:
  • Shell cracks: The robot is subjected to impact, overload or casting defects, which cause cracks in the reducer housing and oil tank.
  • Loose or broken screws: Insufficient pre-tightening force of screws on mating surfaces, or detachment of locating pins, resulting in gaps.
  • Bearing failure: After the bearing wears down, it will cause axial movement, which will expand the inner diameter of the oil seal and damage the seal.

    1.3 Lubrication system problems

• Phenomenon: Oil stains near the filler neck, or abnormally high robot temperature.
• Specific reasons:
  • Oil level too high: Adding more lubricating oil than the upper limit will increase the internal pressure during operation, causing it to be squeezed out from weak points.
  • Oil type error: viscosity is too low (e.g., hydraulic oil is used instead of gear oil) or it is deteriorated or emulsified, resulting in excessive fluidity.
  • Breath plug blockage: When the breather plug is blocked by dust, the internal gas cannot escape, creating positive pressure that causes oil to leak out.

    1.4 Improper use and maintenance

• Phenomenon: Oil leakage is strongly correlated with specific actions or operating conditions.
• Specific reasons
  • Long-term overload: Frequent full-load sudden stops and starts cause a sudden increase in internal pressure.
  • Harsh environment: Dust and moisture enter the sealed contact surface, accelerating wear.
  • Failure to change oil on time: Metal shavings mixed in the lubricating oil can damage the seal like an abrasive paste.

2. Emergency handling recommendations:

2.1 Stop the machine immediately for inspection: If there is a large amount of oil leakage (obvious oil droplets on the ground), or if the robot exhibits abnormal shaking or noise, stop the machine immediately to prevent the reducer from being scrapped due to lack of oil.

2.2 To determine the location of the oil leak: wipe the surface clean and observe after running for a few minutes. Common leak points: joint seams (mostly seals), oil drain/fill screws (may be gaskets or not tightened), oil pipe joints (common in hydraulically driven robots).

2.3 Temporary emergency: For minor oil leaks, add the same type of lubricating oil to continue operation for a short time and arrange for maintenance; for major oil leaks or pressure leaks, do not force operation.

2.4 Fundamental solution: In most cases, the reducer needs to be replaced. This usually requires disassembling the joints; it is recommended to contact the manufacturer or a professional repairman for assistance.

3. Common oil leak high-incidence areas

4. Preventive measures to avoid oil leakage in the reducer:

    4.1 Installation phase

• Ensure installation accuracy
• Choose the right lubricant

    4.2 Daily Use: Key Points of Operation and Monitoring

• Control the oil level: Add lubricating oil to the middle of the oil window or between the oil level mark and the mark. Do not fill it completely (the pressure will increase sharply after high temperature expansion).
• Keep ventilation unobstructed: Regularly check and clean the dust and sludge on the vent plug (breathing valve) to ensure that the internal air pressure is balanced with the outside air pressure.
• Avoid prolonged overload: reduce sudden stops, sudden reversals, and long-term operation at full load to reduce internal shock pressure and temperature rise.
• Temperature monitoring: If the surface temperature of the reducer exceeds 85℃, the machine should be stopped and the cause investigated (high temperature will accelerate the aging of the seal).

    4.3 Regular maintenance: Inspection and replacement cycle

• Daily visual inspection: Before operation, check the ground and robot body for fresh oil stains, and pay special attention to joints, drain plugs, and oil pipe joints.
• Regular oil changes
  • Replace the initial lubricating oil after the first 200-400 hours of operation (to flush out metal filings from the break-in process).
  • After that, change the oil every 2000-3000 hours or once a year (half the time in harsh environments).

    4.4 Environmental adaptation: Targeted protection

• Dusty environments: Install dust caps on the vent plugs and regularly blow out the joint gaps with compressed air to prevent abrasives from entering the sealing interface.
• In humid or chemical environments: Wear corrosion-resistant protective clothing.

Disclaimer: All content is for learning and communication purposes only. If unpredictable problems arise due to your own operation, please bear the risks and consequences of the test yourself.

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