The influence of fatigue pitting on bearing troubleshooting

When the rolling element is loaded, contact stress will be generated on the contact surface between the rolling element and the inner and outer rings. The inner and outer rings and the rolling element have relative rotational motion during operation, so the contact stress will change. When the contact stress exceeds the specified value, fatigue cracks will occur below the surface and gradually expand to the surface, causing fatigue pitting on the surface of the inner and outer ring rolling element, leading to loss of precision bearing rotation accuracy, noise, impact, and vibration, So pitting corrosion is a form of failure in precision rolling bearings. So, let's take a look at the impact of fatigue pitting corrosion on troubleshooting precision bearings together!

Method to increase the service life of precision bearings:

The lifespan of precision bearings is closely related to production, manufacturing, installation and application, so it is necessary to do a good job at each stage to ensure that the precision bearings reach their operating conditions and increase their service life.

1. Selection and operation of dimensional tolerances for shafts and bearing chambers: After the bearing is pressed into the bearing, it should be able to rotate easily without sliding blocks. When the rotation is obviously inconvenient, the size of the shaft is too large. Please reduce the dimensional tolerance. After the precision shaft is pressed into the shaft, if there is a noticeable "looseness" in the rotation it excels at, the dimensional tolerance of the shaft may be large, or the concentricity of the shaft may be poor. Therefore, in the control of dimensional tolerances for precision bearings and precision bearing chambers, it is important to ensure concentricity. At this stage, many Chinese manufacturers can only operate on dimensional tolerances without concentricity.

2. Installation method: Due to the fact that precision bearings are high-precision products, poor installation can easily damage the cross-section of precision bearings, thereby damaging the bearings. The installation of precision bearings requires a specialized type of shell and cannot be knocked casually. Press the axis to apply force only to the circle, and press the large circle to apply force only to the large circle. When installing a standard air pressure or hydraulic press and riveting horizontally from left to right, if there is deviation, the cross-section of the bearing will be damaged by the precision bearing, and the wires of the precision bearing will be damaged.

3. Avoid dirt: When placing the bearing on the motor rotor to achieve dynamic balance of the rotor, the iron pins generated due to the dynamic balance of the rotor are easily inserted into the precision bearing. Therefore, before installing the bearing, keep the rotor in good dynamic balance. Some manufacturers, in order to facilitate installation, install oil or vegetable oil in the bearing chamber to wet the actual effect. However, it is difficult for the actual operator to control the amount of oil or vegetable oil in the precision bearing chamber. If there is a lot of oil or vegetable oil in the chamber, the rotation of the bearing will follow the shaft and adhere to the precision bearing. Do not apply oil or vegetable oil to the precision bearing chamber. When applicable, please do not accumulate in the precision bearing chamber during operation.

4. Prevention of paint rust: The characteristic of paint rust is that it is a closed type motor with multiple occurrences. The sound of the motor during installation is very good, but after being placed in the warehouse for a period of time, the sound of the precision bearing motor becomes very loud, and there is serious rusting of the bearing after disassembly. Previously, many manufacturers believed that it was a problem with precision bearings.