Steps needed for bearing maintenance in daily work：Keeping the bearings lubricated and clean; ensuring the quality of the bearing lubricant; the working environment of the bearings; and the bearing seals.
The bearing shows a strong regularity in its use process, and the repeatability is very good. When the normal high-quality bearing (linear bearing) is used at the beginning, the vibration and noise are relatively small, but the spectrum is a little messy and the amplitude is small, which may be caused by some defects in the manufacturing process, such as surface burrs.
After moving for a period of time, the vibration and noise maintain a certain level, and the spectrum is very single, with only one or two times the frequency. The frequency spectrum of more than three times of power frequency rarely appears, and the bearing state is very undisturbed, so it enters the undisturbed working period.Maintenance technology of bearing under working condition
In the later stage of operation, the vibration and noise of the bearing begin to increase, sometimes with abnormal sound, but the change of vibration increase is slow. At this time, the kurtosis value of the bearing suddenly reaches a certain value. We believe that at this time, the bearing shows initial failure.Maintenance technology of bearing under working condition
In order to maintain the original function of the bearing in good condition for as long as possible, it is necessary to maintain and inspect it in order to prevent accidents, ensure the reliability of operation and improve productivity and economy. Maintenance technology of bearing under working condition
Maintain the scale of corresponding machinery operation premise on schedule. The contents include supervising the operation status, adding or changing lubricants, and inspecting the disassembly on schedule. As the inspection items in operation, there are bearing rotation sound, vibration, temperature, lubricant state, etc.Maintenance technology of bearing under working condition
Bearing cleaning: when disassembling the lower bearing for inspection, first record the appearance of the bearing, confirm the residual amount of lubricant, and wash the bearing after sampling the lubricant for inspection. As a cleaning agent, gasoline and kerosene are commonly used.Maintenance technology of bearing under working condition
The cleaning of the removed bearing is divided into coarse cleaning and fine cleaning. They are placed in the container respectively. First, put the metal mesh bottom so that the bearing does not directly contact the dirt of the container. Maintenance technology of bearing under working condition
During rough cleaning, if the bearing rotates with dirt, it will damage the moving surface of the bearing, which should be paid attention to. In the coarse cleaning oil, use a brush to remove the grease and adhesion. After it is roughly clean, turn to fine cleaning.Maintenance technology of bearing under working condition
Fine cleaning is to carefully clean the bearing while rotating in the cleaning oil. In addition, the cleaning oil should always be kept clean. After the bearing is pressed into the bearing, it shall rotate flexibly without blocking feeling. If there is obvious inflexible rotation, it indicates that the size of the shaft is too large and the tolerance should be reduced. Maintenance technology of bearing under working condition
If the thrust cylindrical roller bearing rotates by hand after being pressed into the shaft, there is an obvious “rusty” feeling, it may be that the tolerance of the shaft is too large or the roundness of the shaft is not good. Therefore, when controlling the tolerance of shaft and bearing chamber, it is also necessary to control the roundness. At present, many domestic manufacturers only control the tolerance, not the roundness.Maintenance technology of bearing under working condition
Because the bearing is a high-precision product, if it is not assembled properly, it is easy to damage the bearing channel, resulting in bearing damage. The thrust cylindrical roller bearing shall be equipped with a special mold during assembly, and can not be knocked at will. Maintenance technology of bearing under working condition
When pressing the shaft, it can only be stressed by a small ring, and when pressing a large ring, it can only be stressed by a large ring. Pneumatic or hydraulic pressure is required during assembly. During press assembly, the upper and lower molds shall be outside the horizontal state. If there is inclination, the bearing channel will be damaged due to stress and the bearing will make a guide sound. Maintenance technology of bearing under working condition
The measures to prevent cage noise are as follows:bearing under working condition
When the grease performance of the bearing is poor under radial load, the noise of “click, click” will be heard at the beginning of operation, which is mainly due to the noise caused by the sudden acceleration of the rolling element and its collision with the cage after leaving the load area. This impact sound is inevitable, but will disappear after a period of operation.Maintenance technology of bearing under working condition
In order to stabilize the rotation movement of the cage, the ring mode should be adopted as far as possible and the surface should be fully lubricated. The structure of tapered roller bearing under high-speed working conditions should be improved. The L-shaped cage of the roller should be changed into the Z-shaped cage with ring retaining edge.Maintenance technology of bearing under working condition
When the bearing rotates at high speed, the vibration amplitude of the cage of the bearing with large pocket clearance is much larger than that of the cage with small pocket clearance, so the value of pocket clearance is particularly important.Maintenance technology of bearing under working condition
Try to improve the manufacturing accuracy of the cage and improve the surface quality of the cage, which is conducive to reducing the noise caused by the collision or friction between the rolling element and the cage.Maintenance technology of bearing under working condition
Actively adopt advanced cleaning technology to effectively and thoroughly clean spare parts and products after assembly, so as to improve the cleanliness of bearings.Maintenance technology of bearing under working condition
Flexible bearing selection and press in tolerance of the shaft. If there is obvious inflexible rotation, it indicates that the size of the shaft is too large and the tolerance should be reduced. If there is an obvious “rusty” feeling when the tapered roller bearing is rotated by hand after being pressed into the shaft, it may be that the tolerance of the shaft is too large or the roundness of the shaft is not good.Maintenance technology of bearing under working condition
Therefore, when controlling the tolerance of shaft and bearing chamber, it is also necessary to control the roundness. At present, many domestic manufacturers only control the tolerance, not the roundness.Maintenance technology of bearing under working condition
Bearing assembly method: because the bearing is a high-precision product, if it is not assembled properly, it is easy to damage the tapered roller bearing channel, resulting in bearing damage. The bearing shall be equipped with a special mold during assembly, which cannot be knocked at will. Maintenance technology of bearing under working condition
When pressing the shaft, only the small ring can be stressed, and when pressing the large ring, only the large ring can be stressed. Air pressure or hydraulic pressure is required during assembly. During press assembly, the upper and lower touch shall be outside the horizontal state. If there is inclination, the bearing channel will be damaged due to stress and the bearing will produce conduction sound.Maintenance technology of bearing under working condition
Prevention of assembly foreign matters: when the tapered roller bearing is installed on the rotor for dynamic balance, it is easy to put the iron filings generated during dynamic balance into the bearing, so it is necessary to perform dynamic balance before installing the bearing.Maintenance technology of bearing under working condition
In order to facilitate assembly, some manufacturers apply some oil or grease in the bearing chamber for lubrication effect during assembly, but it is often difficult for operators to control the amount. If more oil or grease is accumulated in the bearing chamber, it is easy to enter the bearing along the shaft when the bearing rotates. The bearing chamber shall not be coated with oil or grease. If it must be coated, it shall be controlled and there shall be no accumulation in the bearing chamber.Maintenance technology of bearing under working condition
Prevention of paint rust: paint rust is often found in sealed motors. The sound of the motor is very good during assembly, but after being placed in the warehouse for some time, the abnormal sound of the motor becomes very large, and there is serious rust when removing the tapered roller bearing. In the past, many manufacturers thought it was the bearing problem. Maintenance technology of bearing under working condition
After our continuous publicity, now the motor factory has realized that the main problem is the insulating paint. This problem is mainly because the acidic substances volatilized from the insulating paint form corrosive substances at a certain temperature and humidity, which corrodes the bearing channel and leads to bearing damage. At present, the problem can only be to select good insulating paint and assemble after drying and ventilation for a period of time. Maintenance technology of bearing under working condition
There are great differences between the working surface and the core of bearing parts in terms of state, structure and performance requirements, but the overall heat treatment often makes it impossible to take into account, and the potential of materials can not be brought into full play. Maintenance technology of bearing under working condition
The application of material surface strengthening technology can not only better solve the differences in structure and requirements between the surface and the core, but also further make the surface obtain some special working properties to meet the requirements of the bearing working under specific conditions. Maintenance technology of bearing under working condition
This is of great significance in the development of modern science and technology. The traditional surface strengthening method belongs to the category of heat treatment. The surface strengthening methods such as laser, electron beam and ion beam developed in modern times not only apply some high and new technologies to the surface strengthening of materials, but also go beyond the scope of traditional heat treatment and form a new technical field.
Therefore, the current surface strengthening technology can form a variety of classification methods from different angles. According to the physical and chemical process of surface strengthening technology, it can be roughly divided into five categories: surface deformation strengthening, surface heat treatment strengthening, chemical heat treatment strengthening, surface metallurgy strengthening and surface film strengthening.Maintenance technology of bearing under working condition
The method of forming a surface hardening layer by means of high hardness and surface hardening is also known as the method of forming a surface hardening layer. Including shot blasting, sand blasting, cold extrusion, rolling, cold rolling and impact, explosion impact strengthening, etc. Maintenance technology of bearing under working condition
The characteristics of these methods are: the strengthening layer dislocation density increases and the sub crystal structure is refined, so as to improve its hardness and strength and reduce the surface roughness value, which can significantly improve the surface fatigue strength of parts and reduce the sensitivity of fatigue notch. This strengthening method has the advantages of simple process and remarkable effect. Maintenance technology of bearing under working condition
There is no obvious boundary between the hardened layer and the matrix, the structure is coherent, and it is not easy to fall off in use. Most of its methods have been applied in the bearing industry: the surface impact strengthening of rolling element is the application of this kind of method, and precision rolling has become a new ferrule processing and strengthening method.Maintenance technology of bearing under working condition
Quenching the surface layer of parts by means of solid-state phase transformation and rapid heating is called surface heat treatment, commonly known as surface quenching. Including flame heating quenching, high (medium) frequency induction heating quenching, laser heating or electron beam heating quenching, etc. Maintenance technology of bearing under working condition
The characteristics of these methods are: local heating and quenching of the surface, small deformation of the workpiece; Fast heating speed and high production efficiency; The heating time is short, and the surface oxidation decarburization is very slight.Maintenance technology of bearing under working condition
The characteristics of these methods are:under working
In order to maintain the original performance of the bearing in good condition for as long as possible, it is necessary to maintain and repair in order to prevent accidents, ensure the reliability of operation and improve productivity and economy.
Maintain the operation standard of corresponding mechanical operation conditions and carry out it regularly. The contents include monitoring the operation status, replenishing or changing the lubricant, and regular disassembly inspection. As maintenance items in operation, there are bearing rotation sound, vibration, temperature, lubricant state, etc.Maintenance technology of bearing under working condition
Bearing cleaning: when disassembling the lower bearing for maintenance, first record the appearance of the bearing, confirm the residual amount of lubricant, and wash the bearing after sampling the lubricant for inspection. As a cleaning agent, gasoline and kerosene are commonly used.Maintenance technology of bearing under working condition
The cleaning of the removed bearing is divided into coarse cleaning and fine cleaning. They are placed in the container respectively. First, put the metal mesh bottom so that the bearing does not directly contact the dirt of the container.Maintenance technology of bearing under working condition
During rough cleaning, if the bearing rotates with dirt, it will damage the rolling surface of the bearing, which should be paid attention to. In the coarse cleaning oil, use a brush to remove the grease and adhesion. After it is roughly clean, turn to fine cleaning.Maintenance technology of bearing under working condition
According to the load acting on the bearing and the rotation condition of the ferrule, the load borne by the ferrule can be divided into three types: fixed load, rotating load and back and forth shaking load.Maintenance technology of bearing under working condition
Fixed load Maintenance technology of bearing under working condition
The resultant radial load is borne by part of the region of the ferrule raceway and transmitted to the corresponding part of the region of the appropriate surface of the shaft or shell. This load is called fixed bearing load.
The unique feature of the fixed load is that the synthetic radial load is relatively static with the ferrule. Generally, loose ferrules can be used to bear fixed load.
Load shedding
The synthetic radial load vector acting on the bearing ring rotates along the circumferential direction of the raceway, is successively borne by each part of the raceway, and is transmitted to each part of the outer surface of the shaft housing hole accordingly. This kind of load is called off load, also known as cyclic load.
The unique feature of load shedding is that the synthetic radial load vector rotates relative to the ferrule. The ferrule bearing the transfer load and the shaft or shell hole shall be suitable for filtering or interference. If you think it is appropriate to use the gap and install it properly, there will be slip between you and me, which will cause friction damage and friction heating of the contact surface, rapidly increase the temperature and quickly destroy the bearing.
The volume of the desired interference is determined according to the operating conditions, and the principle is that when the bearing is working under the load effect, it will not cause the “crawling” phenomenon of the actuating ferrule on the appropriate surface in the shaft or housing hole.
The synthetic radial load vector acting on the bearing ring relatively swings back and forth within a certain area of the ring raceway, which is borne by a certain area of the raceway and transmitted to a certain area on the surface of the shaft or shell hole, or the load acting on the bearing is impact load and oscillation load, and its load direction or number often changes. This load is called swing load, also known as non directional load.
When the bearing bears back and forth shaking load, especially when bearing heavy load, the inner and outer rings should be considered appropriate and the interference should be used appropriately. When the inner ring swings and rotates back and forth, it is generally considered appropriate by the inner ring, but it is appropriate to use it when the transfer load is removed. Maintenance technology of bearing under working condition
However, sometimes the outer ring must be able to swim towards the bearing outside the housing or when its load is light, it can be considered appropriate to use a slightly looser outer ring than the rotating load.
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