In industrial production and construction, whether the bearings are properly installed will have a certain impact on the operation of mechanical equipment. Therefore, it is necessary to ensure that each component is installed correctly. If the mechanical equipment fails, it will increase the difficulty of bearing disassembly and cleaning, make it noisy in operation, and shorten the service life of the bearing. If the weight of the bearing itself is large, it will be difficult to operate continuously, resulting in bearing damage. Therefore, bearing maintenance is very important. The problems existing in bearing installation and maintenance shall be solved, the overall effect of bearing installation and maintenance shall be improved, the service life of bearing shall be extended, the enterprise cost shall be saved, and the industrial production efficiency shall be improved.

(1) effective methods for bearing installation, disassembly and cleaning

1.1 bearing installation method

Cleaning and treatment methods of bearings and related parts. Before bearing installation, the shaft shall be opened. In general, grease lubricated bearings can be filled with grease to omit the cleaning process [1]. For bearings that do not need clean lubricating oil, clean engine oil shall be used to clean the instrument or high-speed bearing. After cleaning, rust inhibitor shall be applied to the bearing evenly to avoid rust on the bearing surface. In addition, the bearing sealed with grease can omit the cleaning process.

Bearing device method. The bearing is usually composed of shaft rotation. The inner ring should be interference fit during the installation process. The interference fit mode can be applied during the rotation of the outer ring. However, due to the differences in the structure and fitting conditions of the bearing, different installation methods should be applied for different types of bearings. Taking the cylindrical hole bearing device as an example, the cylindrical bearing usually has two methods: press fitting device and hot fitting. One is the press fitting device. With the help of the press equipment, the bolts and nuts shall be applied, and the cushion block shall be padded on the inner ring. Under special circumstances, the device table can be hammered by hand. However, this method will cause improper bearing device, so it is only applicable to the case of small interference and cannot be applied to the bearing with large interference [1]. For non separation type bearings, such as deep groove ball bearings, the inner ring and outer ring shall be installed by interference, and the cushion block shall be well padded. The inner ring and outer ring shall be pressed together by screw or oil pressure. The outer ring of the self-aligning ball bearing is easy to be inclined. Even if the interference fit method cannot be applied, the spacer block needs to be padded before installation. For separation type bearings, such as cylindrical roller bearings and tapered roller bearings, it is necessary to install the inner ring and outer ring on the shaft and the shell, respectively install the inner and outer rings and fuse each other, to ensure that the two are closed, so as to avoid deviation and avoid damage to the raceway surface. Second, the hot charging method. When a large bearing is pressed, it often requires more force, and it is difficult to press. Therefore, the bearing needs to be heated to expand, and then it can be installed on the shaft. This thermal installation method is generally used in the installation of large bearings, which can not only avoid the influence of external force on the bearing, but also complete the installation task in a short time. When the bearing is heated to 95 ℃ ~ 150 ℃, in order to ensure that the bearing does not touch the bottom of the oil tank, it is necessary to place the bearing on the metal mesh or lift the bearing; When heating to 25 ℃ ~ 35 ℃, the inner ring temperature shall be ensured to avoid the gap between the inner ring and the bearing. The installation of tapered hole bearing is to fix the inner ring on the tapered shaft or place it on the cylindrical shaft with a tightening sleeve. Large bearings are generally installed by oil pressure, and the taper hole can be directly installed on the taper shaft or installed by sleeve [2]. In the installation process, there is usually a lot of clearance fit and there is interference in the outer ring. The press equipment can be used to press in or the copper rod can be used to knock in. Since the moisture in the air will condense on the bearing surface, it is necessary to apply appropriate rust inhibitor to avoid bearing rusting.

1.2 disassembly method of bearing

Disassembly method of cylindrical hole bearing. The inner ring can be disassembled by means of pressure mechanical pulling out, which is the most simple and convenient method. It is important to ensure that the inner ring bears the main pulling force. For the disassembly of large bearing inner ring, it is necessary to use the oil pressure method and use the oil hole set on the shaft for oil pressure treatment to facilitate the pulling and pulling of the inner ring; For bearings with large width, the combined method of oil pressure method and drawing card shall be applied to facilitate bearing disassembly; For the disassembly of the inner ring of Nu type and NJ type cylindrical roller bearings, induction heating method shall be applied to conduct local heating treatment in a short time. Based on the principle of thermal expansion and cold contraction, the inner ring can be easily pulled out after being fully expanded.

Disassembly method of tapered hole bearing. For the disassembly of small bearing with fixed sleeve, it is necessary to use the inner ring fastened to the stop support on the shaft, rotate the nut several times, and then knock it with a cushion hammer. For large bearings, it is easier to use the oil pressure disassembly method, that is, the oil is pressurized in the oil hole on the tapered hole shaft, and the inner ring is fully expanded, so that the bearing can be quickly disassembled [3]. In the actual disassembly process, it is easy to have sudden bearing out. The nut should be used as a stop to avoid harm to the staff.

1.3 bearing cleaning method

Conventional cleaning method. Place the bearing in kerosene and control the soaking time at 10-15min. Hold the inner sleeve of the bearing with one hand and rotate the outer sleeve of the bearing with the other hand to ensure that the large area of grease or rust inhibitor of the bearing will fall with the rotation of the bearing [4]. Immerse the bearing in kerosene with high cleanliness, use a soft brush to fully clean the residual lubricating grease or rust inhibitor in the bearing gap, and then put the bearing in gasoline for washing. After taking it out, place it in the oil tank? A clean position is enough.

Hot oil cleaning method. Because the bearing surface is aging and hard, the conventional cleaning method cannot be applied to the grease or antirust agent. It is necessary to immerse the bearing with dry and hard grease in the hot engine oil at a temperature of 100 ° C for cleaning; The lubricating grease will be melted when heated to 100 ℃, and then the bearing shall be clamped with pliers. The dry and hard lubricating grease on the bearing can be cleaned by brush treatment [5]. Under special circumstances, it is necessary to swing the bearing in the hot engine oil for several times to remove the oil stain in the bearing gap.

(2) effective methods for bearing maintenance

2.1 grease lubrication maintenance method

Grease lubrication is usually filled once, and no supplement is required in the later stage. Because the sealing equipment is simple in structure, the grease lubrication maintenance method is widely used. Grease lubrication can ensure that proper grease is filled in the sealed bearing through the sealing form of filling grease. The filling grease can be replenished and replaced at intervals [6]. Different types of bearings need to be lubricated for mechanical equipment. Pipes can be connected to various lubrication positions to achieve centralized grease supply.

2.2 oil lubrication maintenance method

There are many types of oil lubrication, including oil bath lubrication, oil dripping lubrication, splash lubrication, etc. Oil lubrication maintenance is applicable to high-speed bearings with high heat resistance and not suitable for grease lubrication. This maintenance method can reduce vibration and noise [7-8].

(3) problems in the process of bearing installation and maintenance

The installation and maintenance of bearings are affected by traditional thinking concepts. For example, the performance stability of bearings is directly related to the service time. It is not possible to judge whether the equipment is at risk only from the apparent characteristics. It is necessary to attach great importance to the use of equipment, change the traditional cognitive concepts, and pay attention to maintenance and technical updating. If the thinking is stagnant, the sustainable development of engineering technology will be hindered.

Due to the influence of traditional bearing installation and maintenance theory, some staff do not pay attention to the maintenance, repair and daily inspection of bearing equipment. Although the working mode is constantly changing, the maintenance theory and working system are not perfect. In the process of bearing installation and maintenance, the rights and responsibilities are not clear, the employees' work attitude is loose, and they lack initiative, especially the equipment inspection and maintenance are not in place. The installation and maintenance of bearings need professionals, and the comprehensive quality of personnel needs to be strengthened. Some grass-roots workers only understand the maintenance and have insufficient understanding of the accuracy of bearing equipment. Therefore, there are deficiencies in accident investigation and equipment maintenance. Some maintenance personnel are rich in theory and lack of practice. They can only perform shallow maintenance on bearings and lack in-depth research and learning, resulting in more serious problems of the equipment [9].

Different regions have different climatic environment, which puts forward new requirements and challenges to bearing technology. Bearing installation and maintenance standards in different regions are different, so different measures need to be taken for bearing installation and maintenance. However, due to lack of practical experience, the quality of bearing installation and maintenance is mixed. Some staff make judgments based on their subjective consciousness and experience, which is not conducive to the long-term development of bearing installation and maintenance. Traditional bearing maintenance is mainly based on mechanical maintenance. It is necessary to conduct in-depth analysis on bearing data, formulate effective maintenance strategies based on previous experience, and conduct overall deduction on the data based on intelligent simulation calculation. At present, the means of bearing installation and maintenance in some parts of China have not been updated, and there is no overall planning for the maintenance of bearing structural parts. As a result, in areas with large temperature difference in four seasons, parts are damaged to varying degrees under the effect of thermal expansion and cold contraction.

(4) specific strategies for improving the efficiency of bearing installation and maintenance

4.1 strengthen daily inspection and real-time monitoring of bearings

It is necessary to constantly innovate the methods of bearing installation and maintenance, apply modern scientific and technological management methods, and strengthen daily inspection and real-time monitoring. We should be aware of the importance of daily inspection, formulate a complete inspection plan, deal with problems in a timely manner, and clarify the management rights and responsibilities of relevant responsible persons. As the bearing is long along the line, it can not meet the development needs by relying solely on human resources. Therefore, scientific and technological means should be used for real-time monitoring to improve the efficiency of maintenance management. In the process of actual bearing installation and maintenance, it is necessary to make the theory and work system connect reasonably, improve relevant laws, regulations and technical systems, further clarify the responsibilities and authorities of maintenance personnel, and ensure that there are responsibilities that can be traced and checked. All departments shall strengthen information exchange, communicate with each other on bearing installation and maintenance, report problems in time, provide more valuable information for bearing installation and maintenance personnel, give full play to the theoretical advantages of bearing equipment maintenance, and match the work system with the work needs.

4.2 improve the bearing installation and maintenance mode

Formulate the bearing installation and maintenance operation mode that meets the actual needs, implement the post responsibility system, eliminate the traditional single post responsibility division, and try to achieve full participation. The installation and maintenance of bearings should be integrated with advanced technologies such as big data, and attention should be paid to the accumulation of experience. Data records should be made for the problems or daily inspection abnormalities in the past, and corresponding databases should be established to accumulate experience for future work and improve the efficiency and quality of bearing installation and maintenance. It is necessary to realize the unified management of the bearing integrity disease information and monitoring information, realize the sharing of resources and information, including the maintenance data, disease data and line detection data, combine the dynamic data with the static data, use the cloud computing method to check the problems existing in the bearing installation and maintenance, and gradually realize the unification and standardization of the bearing installation and maintenance mode. Adhering to the principle of daily inspection, early detection and early treatment, we will do ideological work from top to bottom, straighten out the work mentality, constantly innovate and optimize the work process and links, and promote the effective improvement of installation and maintenance technology [10].

4.3 pay attention to professional personnel training

In the process of bearing installation and maintenance, we should pay attention to the training of professional personnel and create a technically competent equipment maintenance team. The maintenance work should not only be emergency, but more emphasis should be placed on the daily maintenance and overhaul of equipment, so as to check and solve problems as soon as possible. Relevant departments shall organize equipment maintenance personnel to carry out daily continuing education and study, understand modern advanced equipment maintenance technology, and combine work content with theory. It is necessary to carry out joint training with colleges and universities, pay attention to the introduction of college graduates, and sign employment intention agreements when necessary, so that more students with a solid theoretical foundation can participate in the equipment maintenance industry and inject vitality into the maintenance team. Improve the professional quality of maintenance management personnel and promote the bearing installation and maintenance mode? Benign development, led by the Department, establish safety awareness from top to bottom, strengthen daily training, and enhance their sense of social responsibility. Special skills training shall be conducted regularly to enable all personnel to have a deeper understanding of maintenance details.

(5) conclusion

Bearing installation will affect the operation and production of the equipment. It is necessary to clarify the characteristics of the installed parts, do a good job in bearing maintenance, avoid affecting the actual production, and create greater benefits for the production enterprises.