Destructive form of rolling bearing

      During the operation of rolling imported bearings, abnormal heating, vibration and noise suddenly appear, indicating that the rolling imported bearings may have been damaged, and the reasons should be checked and analyzed in time. Common forms of destruction are:
       1, fatigue spalling
       On the surface of the raceway or rolling element of the rolling inlet bearing, the metal of the surface of the contact surface is peeled off by the action of the alternating load, and gradually expands to form a pit. If the operation continues, an area peeling area will be formed. Due to improper installation or tilting of the bearing housing bore and the centerline of the shaft, the local area of ​​the bearing is subjected to a large load and early fatigue damage occurs.
       2, cracks and fractures
       Improper material defects and heat treatment, too large interference, improper combination design, such as grooves on the bearing surface and stress concentration, etc., will form ferrule cracks and fractures.
       3, indentation
      When the external hard particles enter the bearing and are pressed between the rolling elements and the raceway, the rolling surface can be indented. In addition, an excessive impact load can also cause local plastic deformation of the contact surface to form pits. When the bearing is stationary, even if the load is small, evenly distributed pits will be formed on the raceway due to vibration of the surrounding environment.
      4, wear and tear
      When the rolling bearing is not well sealed, dust or particulate matter enters the bearing, or the lubrication is poor, which will cause more serious scratch or wear on the contact surface and increase the vibration and noise of the bearing.
      5, current corrosion
      Current through the bearing will result in a small spark, resulting in localized annealing of the contact surface and small pits or black highlights. If the situation is serious, large pits will appear.
      6, rust
      Moisture or acid, alkali, salt and other intrusive bearings or improper selection of lubricants will refrain from bearing corrosion. Even if the precision bearings are slightly rusted, the bearings will be scrapped.
      7, the cage is damaged
      Rolling bearings, in particular high-speed bearings, cause wear, collisions, and even breakage of the cage due to the lack of lubricant, causing the cage to contact the rolling elements or ferrules.


      Bearing dust seal
      The life of sealed imported bearings is largely determined by the sealing performance. The commonly used imported bearing seals are folded-edge skeletons. They are generally pressed by hand. The main disadvantages are: poor elastic strength, poor assembly performance and poor sealing performance. .
      The imported bearing dust seal adopts a hook-shaped crimping structure, which has the following advantages compared with the prior art:
      The sealing performance is good and the sealing strength is high. The reason is that the hook-shaped crimping structure of the skeleton effectively increases the elasticity of the sealing ring and maximizes the influence of the difference in the size of the mouth. It not only depends on the elasticity of the sealing elastic body, but also the curling structure. The elasticity and strength function improve the qualification rate of the cover, and the machine pressure can be effectively pressed.

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Classification of rolling bearing fault diagnosis technology

The fault diagnosis technology of rolling bearing mainly includes vibration diagnosis technology, iron spectrum diagnosis technology, temperature diagnosis technology, acoustic diagnosis technology, oil film resistance diagnosis technology and optical fiber monitoring and diagnosis technology. Among them, vibration, iron shop and temperature diagnosis technology are most commonly used.


       1. Vibration diagnosis technology
       When the working surface of the bearing component is subjected to fatigue spalling, indentation or local corrosion, a periodic pulse signal appears in the bearing operation. This periodic signal can be received by a sensor (speed or acceleration type) mounted on the bearing housing to diagnose the bearing fault by analyzing the vibration signal.


       Features: Vibration diagnostic technology is widely used; online monitoring can be realized; diagnosis is fast, and diagnostic theory is mature.

       Scope of application: Particularly suitable for fault monitoring of bearings in rotating machinery.

       2. Ferrography diagnostic technology
       Bearing wear particles are closely related to their working conditions. The lubricating oil with wear particles is passed through a strong magnetic field. Under the action of a strong magnetic field, the abrasive particles are deposited on the iron spectrum according to a certain rule. The iron spectrum can be qualitatively observed on a ferrography microscope or tested on a quantitative instrument. According to this, the working condition of the bearing is judged.

       Features: The machine does not need to be disassembled; the investment is low, the effect is good; the early fatigue failure of the bearing can be found; the wear mechanism can be studied.

       Scope of application: Suitable for fault diagnosis of bearings lubricated with lubricating oil, it is difficult for bearings lubricated with grease.

       3. Oil film resistance diagnosis technology
       A well-lubricated bearing has a large electrical resistance between the inner and outer rings due to the action of the oil film. Therefore, by measuring the resistance of the inner and outer rings of the bearing, the abnormality of the bearing can be judged.

       Features: The same criteria can be used for different working conditions. It has a poor diagnostic effect on abnormalities such as surface peeling, indentation, and cracks.

       Application range: Suitable for occasions where the rotating shaft is exposed.

       4. Optical fiber monitoring and diagnosis technology
       Fiber optic monitoring is a diagnostic technique that extracts signals directly from the surface of the bearing ring. A displacement sensor made of an optical fiber bundle includes an emission fiber bundle and a reception fiber bundle. The light is reflected back from the gap between the end face of the sensor and the surface of the bearing ring by the transmitting fiber bundle, received by the receiving fiber bundle, converted into an electrical signal by the photoelectric element, and the bearing condition can be evaluated by analyzing and processing the electrical signal.

       Features: The fiber displacement sensor has high sensitivity; the signal is directly extracted from the bearing surface, which improves the signal-to-noise ratio; it can directly reflect the manufacturing quality, surface wear degree, load, lubrication and clearance of the rolling bearing.

       Applications: Suitable for machines where the sensor can be mounted in a housing.

       5. Temperature diagnostic technology
       If the bearing produces an abnormality, the temperature of the bearing will change. Therefore, bearing faults can be diagnosed based on changes in temperature, but the ability to judge abnormalities is low.

       Features: Simple diagnosis; better judgment on bearing burns.

       Applications: Simple routine diagnostics for bearings in machines.

       6. Acoustic emission diagnostic technology
       Metal materials need to release elastic waves due to internal lattice dislocations, grain boundary slip or due to the occurrence and development of internal cracks. This phenomenon is called acoustic emission. When the rolling bearing is spalled or cracked, different types of acoustic emission signals are generated, which can be used to evaluate the bearing condition.

       Features: Quick and easy diagnosis; online monitoring.

       Scope of application: New technologies developed in recent years have been used less in bearing condition monitoring.

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