During the daily operation of equipment, an abnormally high bearing temperature is the most common and most easily overlooked warning sign. If not addressed in a timely, it can lead to accelerated wear and tear, or in severe cases, trigger a shutdown or even a safety incident. This article will guide you through identifying and addressing the seven key that cause bearings to "overheat" from a practical perspective, and it also includes scientific temperature measurement methods and safe limit references. 

1. How to accurately measure bearing temperature?

At present, there are two mainstream temperature measurement methods: Contact temperature measurement: Use a point temperature meter to directly adhere to the surface of the bearing seat, which is suitable for precise reading under stable working conditions; Non-contact temperature measurement: Use an infrared thermometer to quickly scan key measurement points such as A and B (usually the outer ring of the bearing or the position of the end cover), which is suitable for high temperature or high-speed operation scenarios.

Note: When the ambient temperature ≤ 40℃, the operating temperature of the bearing should generally not exceed 95℃. Once it approaches or exceeds this threshold, it must be checked immediately!

2. The 7 major culprits behind bearing "high fever"

1. Defect of bearing body: Quality problems at the factory or damage during transportation can cause abnormal internal clearance, rolling body sticking, and thus friction and heat generation.

2. Improper installation: Too tight fit: Incorrect tolerance selection for the shaft or bearing housing, resulting in excessive preload; Too loose fit: Microscopic movement and wear accompanied by vibration and temperature rise; Axiality deviation: Poor alignment of the coupling, causing the bearing to bear additional bending moments; Axial end "locked": No room for thermal expansion, resulting in extrusion and temperature rise.

Case: The bearing temperature at the non-driven end of a fan in a cement plant soared to 110℃ due to excessive locking by the locating sleeve, and returned to normal after stopping and adjusting.

3. Improper lubrication: Too much lubricating grease can cause stirring and heating, and too little cannot form an effective oil film; Grease aging and deterioration or the use of high-viscosity lubricating grease in low-temperature environments will also significantly increase friction resistance.

4. Pollution invasion: Dust, moisture, and other impurities entering the bearing interior destroy the lubrication state and accelerate wear, indirectly pushing up the operating temperature.

5. Thermal conduction interference: Overheating of adjacent components (such as motor rotors, gearboxes), which conduct heat to the bearing area through the shaft or housing.

6. Electrolytic damage: When using variable frequency drives or poor grounding, stray current may flow through the bearing, forming tiny electric sparks on the raceway surface, causing local high temperatures and pitting.

7. Abnormal load: Overload operation of equipment, frequent impact loads, or unreasonable design of the transmission system can all cause bearings to bear stress beyond the rated range, resulting in temperature rise.

3. What to do next?

When bearing temperature is abnormal, do not "treat the symptoms". It is recommended to follow the systematic process of "measurement → recording → comparison → inspection → rectification". If the problem recurs, it is likely to involve deep-seated factors such as lubricant selection or installation process.