During the use of rolling bearings due to their own quality and external conditions, their load-carrying capacity, rotation accuracy and anti-friction performance will change. When the performance index of the bearing is lower than the use requirements and cannot work normally, it is called bearing damage Or failure, once the bearing is damaged or other accidents, there will be various abnormal phenomena such as machine and equipment stalling, damage to functions, etc.
If the bearing is broken, we must first analyze the cause of the failure, and then find a solution. Therefore, it is necessary to investigate and deal with the causes in a short period of time and take corresponding measures.
The factors that cause the bearing to deteriorate are mostly caused by improper use of the bearing? The following explains the factors that cause frequent bearing damage:
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Bearings are wearable parts. As long as they are used, they will definitely be damaged. It only shows up after a certain amount of accumulation. Of course, the damage of rolling bearings is more complicated than that of ordinary mechanical parts. In addition, the damage of rolling bearings is characterized by multiple manifestations and complex reasons. In addition to the internal factors of bearing design and manufacturing, most of the damage of the bearing is due to improper use, such as inappropriate selection, unreasonable support design, improper installation, Caused by external factors such as poor lubrication and poor sealing. The following 8 points are the main factors of bearing damage:
1. Metal corrosion occurs. If there is a lack of lubrication, it is easy to be oxidized by air and rust. To prevent the corrosion of the bearing, do not soak with water. The bearings are made of stainless steel, but they are also afraid of water. When picking up the bearing by hand, thoroughly wash off the sweat from your hands and apply high-quality mineral oil before operation. Pay special attention to rust prevention during the rainy season and summer.
The specific reasons for natural corrosion and wear of bearings are mainly as follows:
① Oxidation wear. The tiny peaks and valleys on the friction surface squeeze each other, causing the brittle surface to gradually fall off and wear. The tiny peaks and valleys on the surface of the bearing's relative motion are combined with oxidation in the air to generate brittle oxides that are not firmly bonded to the base metal. The oxides are very easy to fall off during friction, and the wear that occurs is called oxidative wear.
②Friction generates heat and wear. When the bearing is working under high speed, heavy load and poor lubrication, high temperature is generated at the peak and valley of the surface due to friction, the hardness and wear resistance of the contact point decrease, and even adhesion and tearing phenomenon occur. This kind of wear is called friction heat wear.
③Abrasion of hard particles. If the bearing makes relative motion. The surface of the bearing is uneven in structure, there are hard particles, or impurities such as sand, friction, and cutting chips fall into the surface of the bearing. During the relative movement of the bearing, the hard particles or impurities will scratch the surface of the bearing and even form grooves. This type of wear is called hard particle wear.
④ Pitting erosion. Gears, bearings and other rolling contact surfaces are periodically subjected to large contact pressures during the relative process. After long-term action, fatigue occurs on the metal surface, causing micro cracks and erosion on the bearing surface. This wear is called pitting wear.
Cause rust or corrosion, wear caused by chemical corrosion. The bearing surface is corroded by acid, alkali, salt liquid or harmful gas. The wear process is accelerated, and this wear is called wear caused by chemical corrosion.
Due to temporary contact with water, acid, alkali, salt and other liquids or harmful gases, corrosion damage: non-moving bearings on the equipment. Damage caused by rust or corrosion is called corrosion damage.
2. The bearing is overloaded or used improperly. When in use, the load of the bearing cannot be exceeded. Like a car, the load may be too heavy and the bearing may be easily damaged. Therefore, trucks have more problems than cars, and it is caused by the failure of many parts.
3. The bearing clearance is too small. The front wheel of the car is a diagonal thrust bearing. It needs to adjust the gap. Too loose will cause abnormal noise, deflection, and wheel shaking. Too tight will accelerate wear. Both are bad. Neither is good. For old bearings, Check whether there are burrs, scratches, or cracks on the surface of the ball. Whether the radial clearance and axial clearance of the old bearing are qualified, generally only the radial clearance is measured. For new bearings, first check whether the bearing model is correct.
4. Use inferior bearings. The production of the bearings is produced by some small factories, the production process cannot meet the requirements, the accuracy of the shaft or the bearing box is poor, and the bearing steel is not processed, and it is produced by pressing. So the produced bearings are not durable.
5. Reckless driving may also cause damage to car bearings, but this reason is a bit far-fetched. Because if you drive carelessly, other parts will be damaged before the bearings.
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6. Poor installation. To install the bearing, follow the installation steps of the bearing, don't install and dismantle it brutally. Whether the bearing is installed correctly or not is related to the service life of the bearing, so everyone must pay attention to it. When installing the bearing, avoid holding it directly with your hands, because sweat on your hands may also cause rust. Don't ignore the small links. When installing the bearing, the most important thing is not to allow strong punching and direct hitting of the bearing with a hammer, not for fear of smashing it, but for fear of smashing and deforming, and the deformed bearing will become unusable. There is also no pressure to pass through the rolling elements.
7. Foreign body intrusion. Try to use special tools, and try to avoid using cloth and short fibers, so as to prevent fine fibers from entering the bearing and causing unnecessary damage. For another example, when installing the bearing, the staff used the copper rod knock-in method, which easily caused uneven axial force on the bearing, causing deformation of the cage, damage to the rolling elements, and increased clearance, and the copper rod was knocked in the process. The copper powder flies into the bearing cage and easily causes bearing failure.
8. The hardness caused by abnormal high temperature, the metallographic structure or chemical composition of the metal changes, which reduces the wear resistance and hardness of the bearing surface and accelerates the wear process. This kind of wear is called wear caused by high temperature action. Wear caused by high temperature. When the bearing is temporarily working at a high temperature.
9. Excessive oil in the bearing and the box will cause the rolling elements of the bearing to slip, causing the rolling friction to change from rolling friction to sliding friction, and damaging the rolling elements of the bearing. Due to the excessive amount of oil in the bearing, the free space in the bearing box is small and the bearing runs The temperature will rise, the lubricating grease density will decrease, the lubricating oil film of the rolling elements will become thinner, and the lubrication conditions will be poor, which will easily cause abnormal noise, surface slippage, and shorten the life of the bearing. Generally, there is a bearing oil chamber on the side of the motor end cover. According to the motor speed, the oil filling amount of the bearing chamber can be implemented according to the following standards: when the motor speed is less than 1500r/min, the oil filling amount is 2/3 of the bearing chamber volume. When the speed is between 1500 and 3000r/min, it is 1/2 of the volume of the bearing chamber. When the speed is greater than 3000r/min, it should be less than or equal to 1/3 of the bearing volume. In the actual work process, for bearings that run at high temperatures and high speeds, bearings with sealing surfaces should be used as little as possible, increase the amount of oil in the motor oil cover, and install a refueling nozzle to increase the operating life of the motor bearing.
10. For bearings with an insulation design on the outer ring, care must be taken to ensure that the insulation is intact. If the bearing insulation is damaged during installation, the thin oil film of the bearing will be broken down by the shaft voltage. After the oil film breaks down, not only will the lubrication conditions of the rolling elements be poor, but also the electric sparks generated will cause electric corrosion to the rolling elements of the bearing and cause the rolling elements. The surface is not smooth, which accelerates the wear of the bearing.
Wear of the bearing can be repaired in this way. The solution is to re-study the operating conditions or re-select the bearing, observe the clearance and check the machining precision between the shaft and the bearing bar, check the design around the bearing, study and check the installation method and the lubricant and lubrication method.
The bearings sold by Eric Bearings Limited are of excellent quality, and the price is much cheaper than other distributors. The products are exported to more than 50 countries and regions in the world, winning wide acclaim from customers and establishing long-term cooperative relations with them. In order to expand the scope of business, we also hope to establish trade relations with more customers and develop together.