Bearing damage status and remedial measures

Core Tips: Peeling Damage state: When the bearing is subjected to load rotation, the raceway surface or rolling surface of the inner ring and the outer ring exhibits fish scale-like peeling due to rolling fatigue.  the reason:
Stripping
Damage state: When the bearing is subjected to load rotation, the raceway surface or the rolling surface of the inner ring and the outer ring exhibits a fish scale-like peeling phenomenon due to rolling fatigue.
Reason: The load is too large. Poor installation (non-linear) torque load foreign matter intrusion, water ingress. Poor lubrication, improper lubricant clearance, improper bearing clearance. The accuracy of the bearing housing is not good, and the rigidity of the bearing housing is uneven, the deflection of the shaft is large, the rust, the erosion point, the scratch and the indentation (surface deformation phenomenon) are caused.
Measures: Check the size of the load and the bearing used in the re-inspection to improve the installation method to improve the sealing device and prevent rust during shutdown. Use a lubricant of appropriate viscosity to improve the lubrication method. Check the accuracy of the shaft and bearing housing. Check the clearance.

Peeling
Damage state: It shows a dark surface with slight abrasion. There are many tiny cracks on the dark surface from the surface to 5-10m deep, and tiny shedding (small peeling) occurs in a wide range.
Cause: The lubricant is not suitable. Foreign matter enters the lubricant. Poor lubricant causes a rough surface. The surface finish of the paired rolling parts is not good.
Action: Select a lubricant to improve the seal to improve the surface finish of the paired rolling parts.

Card injury
Damage state: The so-called card injury is a surface damage caused by a combination of minute burns generated in a sliding surface flaw. Linear flaws in the circumferential direction of the slide surface and the rolling surface. The tangential flaw of the roller end face is close to the pinch of the collar surface of the roller end face.
Reason: Excessive load, excessive preload. Poor lubrication. Foreign body bites into it. The inclination of the outer ring of the inner ring and the deflection of the shaft. The accuracy of the shaft and bearing housing is poor.
Action: Check the size of the load. Preload should be appropriate. Improve lubricants and lubrication methods. Check the accuracy of the shaft and bearing housing.

Broken
Damage state: The so-called fracture refers to a small portion of the fracture due to the application of a musical impact or an excessive load to a portion of the rim or the roller angle of the raceway.
Reason: The installation was hit. The load is too large. Poor use, such as falling.
Action: Improve the installation method (hot pack, use the appropriate tool holder). Correct the load conditions. The bearing is mounted in place to support the rib.

Crack, crack
Damage state: The so-called crack refers to the crack damage caused by the race wheel or the rolling element. If it continues to be used, it will also include cracks that develop cracks.
Reason: Too much excess. Excessive load, impact load. Stripping has developed. Heat and fretting wear due to contact of the raceway wheel with the mounting member. The fever caused by creep. The cone angle of the cone shaft is poor. The cylindricity of the shaft is poor. The corner radius of the shaft step is larger than the bearing chamfer and causes interference with the bearing chamfer.
Measures: The amount of interference is appropriate. Check the load conditions. Improve the installation method. The shape of the shaft should be appropriate.

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Motor bearing corrosion analysis and solution

Core Tips: 1 Introduction Some large-scale fan motor manufacturers in Guangdong Province have such a situation. A batch of motor assemblies have not experienced abnormal phenomena during the test run before leaving the factory.
  1 Introduction
Some large-scale fan motor production plants in Guangdong Province have such a situation. A batch of motor assemblies have not experienced abnormal phenomena during the trial operation before leaving the factory. Some of the products were shipped outside the province, and some even exported to the Middle East. However, when the merchants received the goods, they found that the motor rotation noise was abnormally increased. After the motor was disassembled, the motor bearings were found to be seriously rusted, except for the inner diameter and the end face, which were mainly rusted. The rust position is at the contact point between the steel ball and the raceway. Although the rusting procedures are different, it affects the normal operation of the motor, and the merchant returns it. Such accidents not only affected the reputation of the motor factory, but also hindered the normal operation of the motor factory.
The motor manufacturer believes that there is a problem in the bearing quality and anti-rust treatment produced by the bearing factory. They found our bearing product quality inspection station, required to check the quality of the bearing, and assist them to solve the problem of rust of the motor bearing.
2 Motor bearing sample corrosion accident characteristics
Through the production process, production environment, composition of insulating varnish used, grease composition, assembly process, packaging materials, warehouse storage and related production and sales of motor parts and bearing production plants On-site investigation found that the rust accident has the following characteristics:
(1) It mainly occurs in household appliances and office machinery such as ventilation fans and cooling fan motors. The motors used in these machines are mostly several watts to hundreds of watts, and are basically fully enclosed small motors.
(2) The packaged single motor is not found to be abnormal after the trial run of the finished product, and noise increase occurs when it is used for several months after storage. After the motor was disassembled, it was found that the noise was caused by the rust inside the bearing.
(3) Corrosion of the motor bearing is during the manufacturing process or during storage in the warehouse, which is just the highest temperature and humidity in March and April of each year.
(4) The bearings required by the motor factory are generally purchased directly from the bearing factory. The motor factory buys back the bearing that has been rust-proofed by the bearing factory, injects the grease by itself, and then installs it on the rotor of the motor. Most of the grease used for bearings is added to the lithium base oil. It is easy to cause paint rust when using solvent-based paint.
(5) The inside of the bearing is sometimes more serious than the external corrosion. This rust is related to the type and relative humidity of the grease. The ester oil is in the medium humidity (70% RH), and the grease is rusted. Corrosion caused by moisture, rust easily on the outer surface of bearings that are not coated with grease.
(6) Grease has a special paint odor because the grease has deteriorated.
(7) The corrosion of the bearing has obvious directionality, that is, the side of the bearing facing the rotor side of the motor is mostly rusted, and inside the bearing, the surface of the raceway near the rotor and the cage are often rusted.

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