The influence of fatigue pitting on the troubleshooting of precision bearings

When the rolling element is subjected to a load, 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 corrosion on the surface of the inner and outer ring rolling elements, resulting in loss of rotational accuracy, noise, impact, and vibration of precision bearings. Therefore, pitting corrosion is the fault form of precision rolling bearings. So, let's learn about the impact of fatigue pitting corrosion on troubleshooting precision bearings together!

Methods to increase the service life of precision bearings:

The lifespan of precision bearings is closely related to production, manufacturing, installation, and application. Therefore, it is necessary to do a good job at each stage in order to achieve the operating condition of precision bearings 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 it is obvious that rotation is 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 that one is good 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: As precision bearings are high-precision products, poor installation can easily damage the cross-section of the precision bearings, thereby damaging the bearings. The installation of precision bearings requires a specialized type of shell and cannot be lightly tapped. Press the axis once to apply force only to the circle, and press the large circle once 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 bearings on the motor rotor to achieve dynamic balance of the rotor, the iron pins generated by the dynamic balance of the rotor are easily inserted into the precision bearings. Therefore, before installing the bearings, keep the rotor in good dynamic balance. Some manufacturers install oil or vegetable oil inside the bearing chamber for ease of installation to wet the actual effect. However, it is difficult for operators to control the amount of oil or vegetable oil inside the precision bearing chamber. If there is a lot of oil or vegetable oil inside 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 more common in enclosed motors. 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 rust on the bearings after disassembly. Many manufacturers used to think it was a problem with precision bearings.