Overheating is a common problem in paired angular contact bearings that can reduce performance, shorten lifespan, and even cause equipment failure. Below are the main causes and practical solutions to help prevent overheating.

1. Lubrication Problems

Causes:

• Too little grease → leads to dry friction.
• Too much grease → increases resistance and heat from churning.
• Wrong viscosity → high-viscosity oils increase friction at high speeds.
• Contaminated grease → dust, moisture, or debris reduces lubrication quality.

Solutions:

• Use the manufacturer-recommended lubricant (e.g., low-viscosity oil for high-speed applications).
• Clean bearings and replace contaminated grease regularly.
• Upgrade to better seals to prevent contamination.

2. Installation Errors

Causes:

• Incorrect preload:
  • Too much → increases internal friction.
  • Too little → causes vibration and uneven load.
• Misalignment: shaft/housing not aligned properly → uneven stress.
• Improper fits:
  • Too tight → eliminates clearance.
  • Too loose → causes slippage ("creep").

Solutions:

• Set proper preload using torque measurements or thermal methods.
• Check alignment with dial indicators (<0.02 mm tolerance recommended).
• Follow ISO fit standards (e.g., H7/g6 for precision spindles).

3. Load and Design Issues

Causes:

• Excessive loads: axial or radial forces beyond bearing capacity → deformation.
• Wrong contact angle:
  • Small angles (e.g., 15°) for high speed.
  • Large angles (e.g., 40°) for heavy loads.

Solutions:

• Choose tandem (DT) bearings for high unidirectional loads.
• Match contact angle to application (e.g., 25° AC for general CNC spindles).

4. Bearing-Specific Faults

Causes:

• Abnormal internal clearance:
  • Too tight → overheating.
  • Too loose → vibration.
• Material defects: poor steel quality or improper heat treatment.
• Cage or raceway damage: wear or spalling disrupts smooth operation.

Solutions:

• Select correct clearance class (e.g., C2 for preload, C3/C4 for thermal expansion).
• Use certified bearings from reliable brands (e.g., SKF, NSK).
• Replace damaged bearings and inspect for contamination.

5. Environmental Factors

Causes:

• High ambient temperatures: heat expansion reduces internal clearance.
• Contamination: chips, coolant, or dirt entering the bearing.

Solutions:

• Use C3/C4 clearance bearings in high-temperature environments.
• Install non-contact seals (e.g., labyrinth or rubber RS seals) to block contaminants.

Diagnosis & Preventive Maintenance Tips

• Check installation: verify alignment, preload, and fits.
• Test lubrication: ensure correct type, amount, and cleanliness.
• Monitor load conditions: use load cells if needed.
• Use thermal imaging: detect hotspots early for targeted maintenance.

This guide helps identify and resolve overheating issues in paired angular contact bearings quickly and effectively. Proper setup, maintenance, and component selection are key to ensuring long service life and stable performance.