When bearings are used, early damage phenomenon is a common failure of bearings. There are also many forms of early damage to bearings. For example, improper bearing fit, improper installation, and improper maintenance will all cause the imagination of early damage. The specific situation Xiaobian shares the following aspects Early damage caused by improper bearings. 1. Damage caused by unqualified size, shape and position accuracy of the workpiece that cooperates with the bearing If the shoulders of the workpiece shaft and the housing hole are not perpendicular to the mating surface, or the roughness of the bearing positioning surface is unqualified, and due to the bending of the shaft, it will cause the axes of the inner ring and outer ring of the bearing to skew each other and cause the ring and roller The local contact stress on the rolling surface increases significantly, resulting in fatigue spalling and early damage, as shown in Figure 1. If the shell hole of the workpiece is oval or tapered, it will deform the ring and endanger the raceway, which will cause premature wear and fatigue damage of the raceway. Similarly, if the geometry of the matching journal of the workpiece shaft and the bearing is incorrect, it will also cause damage to the raceway of the inner ring of the bearing. If the shaft diameter is too large, the inner ring may be broken, as shown in Figure 2; if the housing aperture is too large, the outer ring will loosen and slip, which will intensify the wear of the housing hole and the outer diameter of the outer ring, as shown in Figure 3 shown. 2. Improper installation and operation methods cause bearing damage The inner assembly and the outer ring of the tapered roller bearing are respectively installed on the shaft and in the housing. During assembly, the ring raceway and the roller may be damaged due to skew, impact or excessive assembly force. If it is small, it will also aggravate the damage of the raceway. If there is a bump on the roller, the bearing will also cause damage to the ring raceway after the bearing rotates, as shown in Figure 4. If the bearing is assembled by pressing in during the installation process, a special sleeve tool must be used, because the ferrule may be cracked or the end face may be damaged by directly hitting the ferrule with an iron rod, and even the rib of the inner ring may be cracked. . In order to avoid cracks, it is not advisable to directly hit the ferrule with an iron rod during installation, but a copper liner must be added. When using a special sleeve tool to assemble the inner components, attention should be paid to the inner and outer diameters of the sleeve, so as not to cause the sleeve to press on the end face of the cage and cause the cage to deform, and the rollers may be scattered when the deformation is serious. During handling and assembly, if the inner components of the bearing are accidentally dropped to the ground or subjected to collision, the cage will be deformed, as shown in Figure 5, the deformed cage will cause the rollers to be stuck, affecting the rotation flexibility of the bearing. In turn, heat and burns are generated, which eventually leads to bearing failure. After the bearing is installed, the adjustment of the clearance between the outer ring and the inner component is also very important. If the clearance is too small, it will lead to excessive temperature rise, accelerated wear and even seizure; if the clearance is too large, additional radial runout and axial The movement causes the relative displacement between the roller and the raceway of the outer ring and causes uneven local wear and noise. Only proper adjustment can ensure the normal operation of the bearing. 3. Damage caused by improper use and maintenance When the bearing is working, if there is insufficient lubricating oil, the direct contact between metal and metal on the working surface will cause abrasions, heat and burns, reduce the original hardness of the bearing and cause adhesive wear, and eventually lead to bearing failure. If the workpiece is not cleaned or the added lubricating oil is not clean (such as mixed with sand, dust, dirt, etc.), or due to unreliable sealing and working in a dusty environment, some hard particles enter the bearing roller before the bearing is installed. The road will cause abrasive wear, and the surface will show fine groove marks or small pits, which will increase the clearance of the bearing, reduce the precision and shorten the service life. If the bearing is subjected to excessive static load or impact load during use, it is likely to cause uneven plastic deformation—indentation—at the contact between the inner and outer rings and the rollers. The appearance of indentation will increase the vibration and noise of the bearing, the temperature will increase, and the wear will increase, which will cause severe peeling and cause the bearing to fail, as shown in Figure 6. This situation mostly occurs on bearings with low speed or swing. Bearings work in humid media and environments with acid vapor and other substances that cause metal corrosion. If the bearing is not well sealed, it may cause corrosion. The mixture of rust products and lubricating oil will cause corrosive wear on the working surface of the raceway and rolling elements, and cause surface spalling. If a current passes through the bearing during use, the current may break through the oil film of the bearing and generate electric sparks, which will cause the surface to melt and form small pits or strip pits, as shown in Figure 7. In order to make the bearing work normally and achieve the expected life, when selecting the bearing, the necessary calculation should be made for the main failure mode of the bearing. For bearings in general operation, the life calculation should be carried out according to the rated dynamic load according to the contact fatigue failure; Strength calculations to prevent plastic deformation from occurring. After the early failure of the bearing, it is necessary to carefully observe the damage, analyze the cause, and take necessary improvement measures. In addition, the design of the bearing combination structure must be reasonable, and sufficient lubrication and reliable sealing must be ensured, which is very important for improving the life of the bearing and ensuring normal operation.  

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