1, the bearing quality is poor or caused damage during transportation and handling before operation. For example, the deepest indentation in the axial middle of the bearing inner and outer ring raceway is caused by road turbulence in the transportation road, and the rotor beats up and down to drive the bearing roller to impact the bearing outer ring raceway.

2, bearing and shaft or bearing chamber coaxial degree does not meet the requirements

3. The outer ring of the bearing that should be able to move axially is crushed by the bearing cover. When the running shaft is extended due to rising temperature, the inner ring of the bearing is driven away from the original axial position, thereby squeezing the ball grinding side raceway and generating more heat.

4, the bearing and the shaft or bearing chamber is too tight, so that the bearing inner ring or outer ring extrusion deformation, radial clearance becomes smaller, rolling is difficult, produce more heat.

5, the bearing and the shaft or bearing chamber is too loose, so that the bearing inner ring on the shaft, the outer ring in the bearing room fast sliding (inner ring sliding is absolutely not allowed, the outer ring has a very slow sliding in many cases is harmless). This friction will produce a lot of heat, will cause a sharp rise in temperature, serious will be in a very short time will damage the bearing, and then produce a fixed rotor friction, winding overcurrent burn and other major accidents.

6, too much grease, too little or deterioration. For the bearing chamber structure with oil baffle, if the grease is not added in time, the phenomenon of too little grease will gradually appear. In addition, the use of high-temperature resistant grease at low temperatures will generate relatively more heat due to its large viscosity.

7. The dust in the environment enters the bearing through the gap between the bearing cover and the rotating shaft, greatly reducing the lubrication function of the grease, increasing the friction resistance, and generating more heat.

8, due to various reasons caused by the rotor overheating, the heat of the rotor is transmitted to the bearing, so that the bearing grease temperature reaches its drop point and becomes liquid and is lost, and the bearing loses lubrication and produces higher heat.

9, when the load bearing more than its rated load, friction and heat will increase, resulting in a rise in temperature.

10, the failure of the cooling system or the poor cooling effect will also cause the bearing temperature to rise.

11, the high temperature environment will cause the bearing temperature to rise, especially in the high temperature environment operating equipment, bearing temperature may be higher. ‌

12, there may be faults inside the bearing, such as damage to the ball or raceway, the fracture of the cage, etc., these faults will lead to increased friction, thus increasing the bearing temperature.