Rolling bearings may be damaged due to various reasons during operation, such as improper assembly, poor lubrication, moisture and foreign body intrusion, corrosion and overload, etc. may cause premature bearing damage. Even under normal conditions of installation, lubrication and operation and maintenance, after a period of operation, the bearings will show fatigue peeling and wear and will not work properly. In short, the cause of failure of rolling bearings is very complicated. The main failure forms and causes of rolling bearings are as follows.
1. The inner and outer raceways and rolling element surfaces of the fatigue peeling rolling bearing both bear the load and relatively roll. Due to the effect of the alternating load, a crack is first formed at a certain depth (maximum shear stress) under the surface, and then extends to the contact surface to make the surface The occurrence of spalling pits and eventually large flaking, this phenomenon is fatigue spalling. Fatigue spalling will cause increased impact load, vibration and noise during operation. Under normal circumstances, fatigue spalling is often the main reason for the failure of rolling bearings. Generally, the bearing life refers to the fatigue life of the bearing, and the life test of the bearing is the fatigue test. The test procedure stipulates that the occurrence of fatigue peeling pits with an area of ​​0.5mm2 on the raceway or rolling body is considered to be the end of bearing life. The fatigue life of rolling bearings is very dispersed. In the same batch of bearings, the maximum life and the minimum life can differ by tens or even hundreds of times, which illustrates the importance of fault monitoring of rolling bearings from another perspective.
2. Wear due to the intrusion of dust and foreign objects, the raceway and rolling elements will cause surface wear during relative movement, and poor lubrication will also increase wear. As a result of wear, the bearing clearance increases and the surface roughness increases, reducing the bearing running accuracy As a result, the accuracy of the machine's movement is reduced, and vibration and noise are also increased. For precision mechanical bearings, the amount of wear often limits the life of the bearing.
In addition, there is a fretting wear. When the bearing does not rotate, due to the action of vibration, there is a slight and repeated relative sliding between the rolling element and the raceway contact surface to cause wear, and a vibration-like wear scar is formed on the raceway surface.
3. Plastic deformation When the bearing is subjected to excessive impact load or static load, or additional load due to thermal deformation, or when a foreign object with high hardness intrudes, dents or scratches will be formed on the raceway surface. This will cause the bearing to produce severe vibration and noise during operation. And once there is an indentation, the impact load caused by the indentation will further cause the nearby surface to peel off.
4. Corrosion Corrosion is one of the most serious problems of rolling bearings. High-precision bearings may be unable to continue to work due to the loss of precision due to surface corrosion. Moisture, acid or alkaline substances directly invading people will cause bearing rust. When the bearing stops working, the bearing temperature drops to the dew point, and moisture in the air condenses into water droplets and attaches to the bearing surface, which can also cause rust. In addition, when current flows inside the bearing, the current may pass through the contact points on the raceway and the rolling element, and a very thin oil film causes electric sparks to cause erosion, forming rubbing-like irregularities on the surface.
5. Fracture Excessive load may cause fracture of bearing parts. Grinding, heat treatment, and improper assembly can all cause residual stress. Excessive thermal stress during operation can also cause bearing parts to break. In addition, improper assembly method and assembly process may also cause the bearing ring flange and roller chamfer to drop out.
6. Gluing When working under poor lubrication and high-speed heavy-load conditions, due to friction and heat, bearing parts can reach a very high temperature in a very short time, resulting in surface burns and gluing. The so-called gluing refers to the phenomenon that the metal on the surface of one part adheres to the surface of another part.
7. Damage to the cage may cause deformation of the cage due to improper assembly or use, increase the friction between it and the rolling elements, and even make some rolling elements stuck and unable to roll, it may also cause friction between the cage and the inner and outer rings, etc. . This damage will further exacerbate vibration, noise and heat, resulting in bearing damage.
1. The inner and outer raceways and rolling element surfaces of the fatigue peeling rolling bearing both bear the load and relatively roll. Due to the effect of the alternating load, a crack is first formed at a certain depth (maximum shear stress) under the surface, and then extends to the contact surface to make the surface The occurrence of spalling pits and eventually large flaking, this phenomenon is fatigue spalling. Fatigue spalling will cause increased impact load, vibration and noise during operation. Under normal circumstances, fatigue spalling is often the main reason for the failure of rolling bearings. Generally, the bearing life refers to the fatigue life of the bearing, and the life test of the bearing is the fatigue test. The test procedure stipulates that the occurrence of fatigue peeling pits with an area of ​​0.5mm2 on the raceway or rolling body is considered to be the end of bearing life. The fatigue life of rolling bearings is very dispersed. In the same batch of bearings, the maximum life and the minimum life can differ by tens or even hundreds of times, which illustrates the importance of fault monitoring of rolling bearings from another perspective.
2. Wear due to the intrusion of dust and foreign objects, the raceway and rolling elements will cause surface wear during relative movement, and poor lubrication will also increase wear. As a result of wear, the bearing clearance increases and the surface roughness increases, reducing the bearing running accuracy As a result, the accuracy of the machine's movement is reduced, and vibration and noise are also increased. For precision mechanical bearings, the amount of wear often limits the life of the bearing.
In addition, there is a fretting wear. When the bearing does not rotate, due to the action of vibration, there is a slight and repeated relative sliding between the rolling element and the raceway contact surface to cause wear, and a vibration-like wear scar is formed on the raceway surface.
3. Plastic deformation When the bearing is subjected to excessive impact load or static load, or additional load due to thermal deformation, or when a foreign object with high hardness intrudes, dents or scratches will be formed on the raceway surface. This will cause the bearing to produce severe vibration and noise during operation. And once there is an indentation, the impact load caused by the indentation will further cause the nearby surface to peel off.
4. Corrosion Corrosion is one of the most serious problems of rolling bearings. High-precision bearings may be unable to continue to work due to the loss of precision due to surface corrosion. Moisture, acid or alkaline substances directly invading people will cause bearing rust. When the bearing stops working, the bearing temperature drops to the dew point, and moisture in the air condenses into water droplets and attaches to the bearing surface, which can also cause rust. In addition, when current flows inside the bearing, the current may pass through the contact points on the raceway and the rolling element, and a very thin oil film causes electric sparks to cause erosion, forming rubbing-like irregularities on the surface.
5. Fracture Excessive load may cause fracture of bearing parts. Grinding, heat treatment, and improper assembly can all cause residual stress. Excessive thermal stress during operation can also cause bearing parts to break. In addition, improper assembly method and assembly process may also cause the bearing ring flange and roller chamfer to drop out.
6. Gluing When working under poor lubrication and high-speed heavy-load conditions, due to friction and heat, bearing parts can reach a very high temperature in a very short time, resulting in surface burns and gluing. The so-called gluing refers to the phenomenon that the metal on the surface of one part adheres to the surface of another part.
7. Damage to the cage may cause deformation of the cage due to improper assembly or use, increase the friction between it and the rolling elements, and even make some rolling elements stuck and unable to roll, it may also cause friction between the cage and the inner and outer rings, etc. . This damage will further exacerbate vibration, noise and heat, resulting in bearing damage.
Coffee Tables For Sale,Oak Coffee Table,Travertine Coffee Table,Grey Coffee Table
CAMOSA HOME , https://www.camosa-funiture.com