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Lubrication Methods, Advantages and Disadvantages of Rolling Bearings

1. Purpose of lubrication:Lubrication Methods, Advantages and Disadvantages of Rolling Bearings

The lubrication purpose of rolling bearing is to reduce the internal friction and wear of bearing and prevent burning and sticking. Its lubrication effect is as follows:Lubrication Methods, Advantages and Disadvantages of Rolling Bearings

1) Reduce friction and wear

The contact parts of the ring, rolling element and cage constituting the bearing prevent metal contact and reduce friction and wear.Lubrication Methods, Advantages and Disadvantages of Rolling Bearings

2) Extend fatigue life

The fatigue life of the rolling element of the bearing is prolonged when the rolling contact surface is well lubricated during rotation. On the contrary, if the oil viscosity is low and the lubricating oil film thickness is not good, it will be shortened.

3) Eliminate friction heat and cooling

Circulating oil supply method can use oil to discharge the heat generated by friction or the heat transmitted from the outside to play the role of cooling. Prevent the bearing from overheating and the lubricating oil from aging.

4) Others

It also has the effect of preventing foreign matters from invading the interior of the bearing, or preventing rust and corrosion.Lubrication Methods, Advantages and Disadvantages of Rolling Bearings

2. Lubrication methods and advantages and disadvantages:Lubrication Methods, Advantages and Disadvantages of Rolling Bearings

The lubrication methods of bearings are grease lubrication and oil lubrication respectively. In order to make the bearing function well, first of all, choose the lubrication method suitable for the use conditions and purposes. If only lubrication is considered, the lubricity of oil lubrication is dominant. However, grease lubrication has the advantage of simplifying the structure around the bearing.

2. Lubrication methods and advantages and disadvantages

The lubrication methods of rolling bearings are grease lubrication and oil lubrication respectively. In order to make the rolling bearing function well, first of all, we should choose the lubrication method suitable for the use conditions and purposes. 

If only lubrication is considered, the lubricity of oil lubrication is dominant. However, grease lubrication has the advantage of simplifying the structure around the bearing.

When disassembling the lower rolling bearing for maintenance, first record the appearance of the rolling 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.Lubrication Methods, Advantages and Disadvantages of Rolling Bearings

The cleaning of the removed bearing is divided into coarse cleaning and fine cleaning. Put the metal mesh pad bottom in the container respectively, so that the rolling bearing does not directly contact the dirt of the container.

 During rough cleaning, if the rolling bearing rotates with dirt, it will damage the rolling surface of the rolling 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.

Fine cleaning is to carefully clean the rolling bearing while rotating in the cleaning oil. In addition, the cleaning oil should always be kept clean.Lubrication Methods, Advantages and Disadvantages of Rolling Bearings

Lubricating oil contains a variety of additives, and the additives added by different brands of lubricating oil are not necessarily the same. Some additives will produce antagonistic effect and reduce performance after mixing. Therefore, try not to mix lubricants of different brands to avoid accidents.

Lubrication Methods, Advantages and Disadvantages of Rolling Bearings

● blackening of lubricating oil is mostly normal

When the technical condition of the engine is normal and the quality of the fuel and lubricating oil used meets the requirements, it is normal that the color of the lubricating oil in use gradually deepens until it turns black.

1. The residue after fuel combustion is miscible in lubricating oil.

2. When the lubricating oil works at high temperature, natural oxidation occurs.

3. Lubricating oil has strong cleaning and dispersing ability to dissolve or disperse oxides, colloids and asphaltenes in lubricating oil.

The quantity of these substances increases with the extension of working time, and the color will gradually deepen and turn black.

The grease has strong adhesion and high oil film strength; It is not easy to leak, the sealing is simple, no sealing equipment is required, the economy is good, and it does not need to be replaced frequently. 

Some can even be used when the machine needs overhaul. However, grease lubricated bearings also have some disadvantages. The friction resistance of grease is larger than that of lubricating oil, which will cause some friction damage to the bearings. 

Moreover, grease does not have the same lubrication effect as lubricating oil, which will cause the bearing to rise in temperature during bearing rotation, so that the bearing temperature is too high. However, we can minimize the phenomenon of bearing temperature rise. 

Too much grease will generate excessive heat, which will not only reduce the service life of the bearing, but also make the grease melt and fail. In view of this situation, according to experience, the filling amount of grease can be 1 / 3-1 / 2 of the bearing space, but for high-speed rotating bearings, the filling amount of grease is not allowed to exceed 1 / 3. 

For bearings that will produce high temperature when rotating at high speed, the grease should be changed frequently.Lubrication Methods, Advantages and Disadvantages of Rolling Bearings

When the mechanical parts near the bearing have been lubricated with lubricating oil or need to be dissipated by lubricating oil, the bearing shall be lubricated with oil. When the bearing is under heavy load or high speed, or there is external heat transfer, there may be heat dissipation requirements. At this time, we use lubricating oil for lubrication. Lubricating oil lubrication is divided into oil bath lubrication, drip lubrication, circulating oil lubrication, oil spray lubrication and oil mist lubrication. Lubrication Methods, Advantages and Disadvantages of Rolling Bearings

The micro lubrication method, such as oil drop lubrication, oil mist lubrication or oil-gas lubrication, can ensure that the oil mixing loss and bearing friction are very small. When air is used as a carrier, it can directly supply oil and make the air flow contribute to sealing. 

Where the bearing speed is very high and good cooling is required, a large amount of lubricating oil can be sprayed directly on all contact surfaces. The lubricating oil lubrication is suitable for high-speed rotation; Lubrication Methods, Advantages and Disadvantages of Rolling Bearings