What are the specific signs before the bearing of a speed reducer fails

1、 Abnormal noise symptoms (the most intuitive early signals)

At the beginning, there is a uniform and fine rustling sound, indicating insufficient lubricating grease, oil film rupture, and slight dry grinding of the rolling elements.

Subsequently, there was a periodic clattering/impact sound, and the rolling elements made a regular abnormal noise every revolution, indicating that the raceway had undergone pitting and peeling.

In the later stage, it developed into sharp whistling/metal friction sound, which is a precursor to severe oil shortage, broken retaining frame, and inner and outer ring locking.

The noise fluctuates between large and small, indicating that impurities such as dust and metal abrasive particles enter the bearing chamber, accelerating internal wear.

2、 Abnormal temperature signs (the most quantifiable inspection indicator)

If the temperature rise of the bearing exceeds 35 ℃ and continues to rise, the normal operating bearing temperature should be ≤ 70 ℃.

If the temperature difference between the input and output bearings of the gearbox exceeds 10 ℃, there is a high probability of potential faults on the high-temperature side.

If the temperature rises rapidly within half an hour of starting up, it indicates that the lubrication has failed or there is a blockage inside the bearing, and continuing to operate can easily cause overheating and locking.

3、 Signs of excessive vibration (core monitoring basis)

The radial vibration has significantly increased, indicating pitting and eccentricity of the raceway, and the gear meshing impact continues to be transmitted to the bearing area.

Abnormal and prominent axial vibration indicates that the thrust bearing has been damaged, with shaft displacement and severe excessive end cap clearance.

The vibration meter captures the characteristic frequencies BPFO/BPFI/BSF of the bearing, which directly correspond to early damage to the raceway and rolling elements.

After loading, the vibration rapidly amplified, and only slightly relieved after unloading, indicating that the bearing clearance has seriously exceeded the standard and the support rigidity has failed.

4、 Signs of abnormal oil and seal (key to predicting potential hazards)

The lubricating oil turns black and a large amount of ferromagnetic metal powder settles at the bottom, indicating that the bearing has developed abrasive wear.

The emulsification and whitening of lubricating oil, as well as water ingress, indicate that water vapor has entered the bearing chamber, and the raceway has begun to corrode, resulting in pitting corrosion.

The oil seal continues to leak oil, and after the seal fails, dust and corrosive media continue to invade the bearing, accelerating internal wear.

5、 Signs of abnormal operating conditions (warning of imminent failure)

The motor current fluctuates significantly, with a significant increase in current after loading, and the bearing rotation resistance has significantly increased.

The axial and radial displacement of the output shaft exceeds the standard, the coupling frequently deviates from the center, and the elastic block is repeatedly damaged.

When stopping and turning, the resistance is uneven, with obvious jamming and sticking points, and in severe cases, the shaft cannot be turned.