Contact fatigue failure
Contact fatigue failure refers to the failure of the FAG bearing working surface subjected to alternating stress. Contact fatigue spalling occurs on the working surface of sliding bearings, and it is often accompanied by fatigue cracks. It is first generated from the large alternating shear stress below the contact surface, and then spreads to the surface to form different spalling shapes, such as pitting or pitting. , Peeling into small pieces called shallow peeling. Due to the gradual expansion of the exfoliation surface, it often expands deeper and forms deep exfoliation. Deep spalling is the fatigue source of contact fatigue failure. ERIC BEARING FAG NJ415-M1-C3 online ， pls click here :
Clearance change failure
In the work of FAG bearings, due to the influence of external or internal factors, the original fit gap is changed, the accuracy is reduced, and even the "bite" is called the clearance change failure. External factors such as excessive interference, inadequate installation, expansion caused by temperature rise, instantaneous overload, etc. Internal factors such as residual austenite and residual stress in an unstable state are the main reasons for the failure of the clearance change.
Wear failure refers to the failure caused by the continuous sliding wear of the metal on the working surface caused by the relative sliding friction between the surfaces. Continued wear will cause gradual damage to bearing parts, and eventually lead to loss of dimensional accuracy of sliding bearings and other related problems. Wear may affect the shape change, the increase in the clearance and the change in the surface morphology of the working surface may affect the lubricant or contaminate it to a certain degree and cause the lubricating function to be completely lost, so that the bearing loses its rotation accuracy and even cannot operate normally. Wear failure is one of the common failure modes of various types of bearings. According to the form of wear, it can be divided into the most common abrasive wear and adhesive wear.
First of all, a reasonable structural design and advanced nature will have a longer bearing life. The manufacturing of FAG bearings generally goes through multiple processing procedures such as forging, heat treatment, turning, grinding and assembly. The rationality, advancement and stability of each processing technology will also affect the life of the bearing. Among them, the heat treatment and grinding processes that affect the quality of the finished bearing are often more directly related to the failure of the bearing. In recent years, the study of bearing on the working surface metamorphic layer shows that the grinding process is closely related to the bearing surface quality.
The metallurgical quality of FAG bearing materials used to be the main factor affecting the early failure of rolling bearings. With the progress of metallurgical technology (such as vacuum degassing of bearing steel, etc.), the quality of raw materials has been improved. The proportion of raw material quality factors in the analysis of bearing failure has decreased significantly, but the bearing is still one of the main factors affecting bearing failure. ERIC BEARING FAG 22207 E1 online ， pls click here :
Due to the relative movement of the rolling elements and the raceway and the intrusion of pollutant dust, the surfaces of the rolling elements and the raceway are worn. When the amount of wear is large, the bearing, noise, and vibration increase, which reduces the running accuracy of the bearing, which directly affects the accuracy of some hosts. Therefore, the daily maintenance of bearings for some silent machinery is mainly to prevent the intrusion of pollutants and dust.
1. Impact on bearing life
The cleanliness of FAG bearings has a considerable impact on the life of needle roller bearings. Bearings have been specially tested for this purpose, and the result is that the difference is several times or even tens of times. The higher the cleanliness of the bearing, the longer the life. The tests of others showed that: the lubricating oil of different cleanliness has a great influence on the life of the ball bearing. Therefore, improving the cleanliness of the lubricating oil can extend the life of the bearing. In addition, if the lubricating particles contained in the lubricating oil are controlled below 10um, the life of the bearing will also increase several times.
2. Impact on vibration and noise
The test results of the FAG bearing test center show that the cleanliness seriously affects the vibration level of the bearing, especially the vibration in the high frequency band is more significant. The vibration value of bearings with high cleanliness is low, especially in the high frequency band. The effect of dust in needle roller bearing grease on noise has been tested, and the more dust, the greater the noise.
3. Influence on lubricating performance
The decrease of bearing cleanliness not only affects the formation of lubricating oil film, but also causes the deterioration of the grease and accelerates its aging, thereby affecting the lubricating performance of the grease to decline.