When the moving body is subjected to a load, contact stress is 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 occur below the surface layer 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 the precision bearing. Therefore, pitting corrosion is a fault form of rolling precision bearings. So, let's learn about the impact of fatigue pitting corrosion on the troubleshooting of 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, doing well in each stage is necessary to ensure that 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 bearing is pressed into the shaft, if there is a noticeable "looseness" in the rotation that is good at, the dimensional tolerance of the shaft may be large, or the concentricity of the shaft may not be good. Therefore, in the control of dimensional tolerances for precision bearings and precision bearing chambers, it is important to ensure good 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 precision bearings, thereby damaging the bearings. The installation of precision bearings requires a specialized type of shell and cannot be struck randomly. 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 pneumatic or hydraulic press and riveting horizontally from left to right, if there is a 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 bearings on the motor rotor to achieve dynamic balance of the rotor, the iron pins generated by the rotor's dynamic balance are easily inserted into the precision bearings. Therefore, maintain good dynamic balance of the rotor before installing the bearings. Some manufacturers install oil or vegetable oil in the bearing chamber to wet the actual effect for ease of installation, but 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. The precision bearing chamber should not be coated with oil or vegetable oil. When applicable, please do not store it in the precision bearing chamber during operation.
4. Prevention of paint rust: The characteristic of paint rust is its frequent occurrence in enclosed electric motors. The sound of the motor is very good during installation, but after being stored in the warehouse for a period of time, the sound of the precision bearing motor becomes very loud, and the bearings have serious rusting when disassembled. Many manufacturers used to think it was a problem with precision bearings.
