How to maximize bearing life

How to maximize bearing life

How to maximize bearing life

In theory, the service life of rolling bearings in centrifugal pumps is 20,000 to 80,000 hours, but the actual life depends on many

factors-premature bearing failure can lead to costly equipment shutdowns, and sometimes even more serious consequences. Bearing experts from NKE (Austria) provided some simple but practical tips for optimizing bearing performance. ..

. A satisfactory bearing service life begins with the correct bearing selection. From the beginning, bearing designers have extended bearing life and equipment performance by choosing the right bearings for different applications. Many factors must be considered in this process, such as load, hardness, bearing life prediction, operating environment and so on. ... Correct storage

In principle, all bearings should be stored in their original packaging before installation. They need to stay in a clean, moisture-free,

relatively constant temperature environment. Rolling bearings should be kept away from dust, water and corrosive chemicals. Shake and vibration may permanently destroy the mechanical properties of the bearing, so vibration must be avoided during handling and storage. ...

Basically, all bearings must be stored horizontally, because some heavy bearings may deform due to their own weight after being placed vertically for a long time. ...

Bearings pre-coated with grease (or sealed) need to be especially careful because the density of grease will change after a long period of storage. In this way, when the bearing is used for the first time, there will be a certain degree of rotating noise. Therefore, the shelf time of this kind of bearing should be controlled according to the principle of first in, first out. ...

Clean

Cleanliness is very important for rolling bearings. The surface roughness of the rotating surface of the bearing ring and rolling elements is usually 1/10 μm. Such a smooth surface is very sensitive to damage caused by contaminants. The lubricating layer between the rotating surfaces is usually 0.2 to 1 μm. Particle-type impurities larger than the lubricant particle size will be excessively crushed by the rolling elements and generate local pressure in the bearing steel, which will eventually lead to permanent material fatigue. In addition to this, the size of dust particles in the external environment can reach 10 μm, which can also cause damage to the bearing. Therefore, a clean and dust-free environment is essential for the storage and installation of bearings. ..

. Fully prepare for re-installation

Bearings should be carefully installed and disassembled using appropriate tools. Industry experts estimate that 16% of premature bearing failures are due to incorrect installation. For a large number of installations (such as in production equipment), the installation conditions are usually strictly controlled, and suitable bearing installation equipment can also be used. ...

However, in the maintenance or replacement work, the environment is diverse. Therefore, in order to ensure the longest bearing life, comprehensive preparations are necessary for bearing installation. ...

First of all, relevant documents, such as drawings, maintenance manuals, product manuals, etc., need to be carefully studied. Next, all bearing components such as shafts, distance rings, covers, gaskets, etc. must be kept absolutely clean and free from contamination. The condition of neighboring components should also be carefully checked. ...

Install and remove carefully

Choose the appropriate installation method (mechanical or hydraulic) and tools according to different applications and bearing sizes and types. Here are some basic principles of bearing installation:

1. Do not apply installation force on the rolling elements. This can easily lead to local overloading of the contact surfaces of the rolling elements and the races, leading to premature bearing failure. ...

2. Do not use any hard tools (such as hammers, screwdrivers, etc.) to directly hit the bearing surface, which may cause the bearing ring to break or chip. ...

3. Follow the guidance of the respected installation equipment supplier. ...

Approximately 90% of rolling bearings have never been removed from the equipment where they are located, and usually only larger bearings are removed due to scheduled preventive maintenance procedures. As with the installation of a bearing, careful preparations must be made for dismounting the bearing. During the disassembly process, ensure that adjacent components such as the shaft and sleeve are not damaged. Choose suitable methods and tools according to bearing type, size and application. ...

Designers should note that a well-designed bearing position can greatly simplify the installation and disassembly of the bearing, thereby reducing maintenance costs. ...

Correct and appropriate lubrication

Lubricants can isolate metal bearing surfaces (such as rolling elements, bearing rings, and bearing covers), thereby reducing friction, protecting metal parts, and preventing pollution and impurities. There are a variety of lubricants (including grease, oil and solids) for different operating conditions. The correct selection of lubricants is very important to prolong the service life of bearings and equipment. ...

Due to the excessive rolling of the rolling parts, the bearing lubricant is subject to long-term mechanical pressure. In addition, the chemical properties of the lubricant will change over time, especially in a high-temperature, humid or polluted environment. All these have led to a gradual decline in lubrication quality. Therefore, to ensure the longest service life, the bearings should be relubricated regularly. The lubrication cycle depends on the operating conditions, such as temperature, speed, environment, etc. Only in pre-lubricated or sealed bearings (also known as "lubricated for life" bearings), bearing life is dependent on lubricant life. ...

Lubricants must be stored correctly in accordance with the manufacturer's instructions, and special attention must be paid to keeping the lubricant clean and free from contamination. Before each use, carefully check the quality of the lubricant. Using old or contaminated lubricants may cause premature bearing failure. ...

Condition monitoring/maintenance

Generally speaking, rolling bearings are very reliable, despite their limited life. Like all other important parts of the machine, they should be inspected and maintained regularly. The frequency of inspection and maintenance depends on the importance of the individual application and the operating conditions of each device. ...

Due to the critical role of the bearing, it is recommended to add a condition monitoring function in its design stage. Important parameters of machine operation, such as vibration and noise, can be continuously monitored, and preventive measures can be taken before unpredictable and costly equipment shutdowns. ...

Training-the basis of good practice

Practice makes perfect, but proper training is the basis of practice. Well-known bearing manufacturers provide various training courses for business, technical or workshop employees. If technicians have basic knowledge in handling bearings, major mistakes can be avoided. Design and product development engineers can maximize equipment performance and minimize life cycle costs by optimizing bearing design. ...

Bearings are usually important components in pumps and other equipment. Although first-class quality bearings are very reliable, more attention must be paid to ensure that they have the longest service life. Correct storage, careful installation and disassembly, adequate lubrication and relubrication, correct condition monitoring, timely maintenance, and finally complete personnel training are all very important to improve bearing service life and equipment performance.

Correct use and common faults of rolling bearings

There are dozens of types of bearings in automobiles that are rolling bearings, including almost all common bearing types, large and small, and collision and damage of rolling bearings are also common. Because rolling bearings are generally installed inside the mechanism, it is inconvenient to inspect visually. You can only make a rough judgment based on the failure phenomenon, and then disassemble and inspect.　

The correct use of rolling bearings is a reliable guarantee for reducing bearing failures and prolonging bearing life. Its contents include correct installation and reasonable lubrication.　　

The following introduces the use requirements and common faults and damages of rolling bearings.　　

1. The correct use of rolling bearings 　

　 1. Disassembly and assembly of the bearing 　

　 The bearing should be cleaned before installation. When installing, use special tools to press in the auxiliary bearing straight and evenly. Do not strike with a hammer. It is especially prohibited to strike directly on the bearing. When the bearing race is loose with the seat hole, the seat hole should be repaired or the bearing should be replaced. Do not use the method of pitting or pad copper on the bearing mating surface. When disassembling the bearing, use a suitable puller to pull the bearing out. Do not hit the bearing with a chisel, hand hammer, etc.　　

2. Lubrication of bearings 　　

Commonly used lubricants for rolling bearings are lubricating oil and grease. When the peripheral speed of the shaft is less than 4　-5m　/s, or the parts on the car that cannot be lubricated with lubricating oil, grease lubrication is used. The advantage of grease lubrication is that the sealing structure is simple, the grease is not easy to lose, and it is not affected by temperature. It can be used for a longer time with one grease.　　

Two problems should be paid attention to when using lubricating grease. One is to select the appropriate brand of lubricating grease according to the requirements of the car manual. For example, it is not suitable to use nano-based grease for automotive water pump bearings because of its poor water resistance. The second is to add a proper amount of grease to the bearing. Generally, it is only suitable to fill 1/2-l/3 of the bearing cavity. Too much is not only useless, but also increases the running resistance of the bearing, causing it to heat up and heat up. Special attention should be paid to automobile wheel bearings. "Empty hub lubrication" should be promoted, that is, only an appropriate layer of grease should be applied to the bearing. Otherwise, it will not only waste and poor heat dissipation, but also cause the grease to be heated and overflow, which may affect Braking performance.　　

The advantage of lubricating oil is low frictional resistance and heat dissipation. It is mainly used for bearings with high speed and high working temperature. The brand of lubricating oil should be selected according to the requirements of the car manual, and replaced in time after the car maintenance cycle. After the old oil is discharged, the mechanism should be cleaned before adding new oil. The fuel should be added to the specified line or flush with the fuel filler. (It depends on the specific structure and requirements of the car), no more.　　

2. Common faults of rolling bearings 　　

There are generally two kinds of failure phenomena of rolling bearings, one is the temperature of the bearing installation part is too high, and the other is the noise during the operation of the bearing.　

　 1. The bearing temperature is too high 　

　 When the mechanism is running, the part where the bearing is installed is allowed to have a certain temperature. When touching the housing of the mechanism with your hand, it should be normal to not feel hot, otherwise it indicates that the bearing temperature is too high.　　

The reasons for the excessively high bearing temperature include: the quality of the lubricating oil does not meet the requirements or deterioration, the viscosity of the lubricating oil is too high; the mechanism assembly is too tight (insufficient clearance); the bearing assembly is too tight; the bearing race rotates on the shaft or in the housing; Large; the bearing cage or rolling elements are broken, etc.