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Comparison of rolling bearings and plain bearings

For the use of bearings, the friction properties of mounting bearings can be divided into rolling bearings and sliding bearings, we can choose different bearing types according to the specific requirements of use, rolling bearings and sliding bearings have different characteristics of use,

The main features of rolling bearings are:

1. Small friction damping (relative to non-liquid friction sliding bearing), flexible start-up;

2. It can bear radial and axial loads at the same time, simplifying the supporting structure;

3. The radial clearance is small, and the clearance can also be eliminated by the preloading method, so the rotation accuracy is high;

4. Good interchangeability and easy maintenance.

 

The main features of plain bearings are:

1. Stable work and no noise;

2. High rotation accuracy;

3. Small friction loss during liquid lubrication;

4. Small radial size;

5. High bearing capacity.

 

What are the advantages and disadvantages of rolling bearings compared with plain bearings? The analysis is as follows:

 

Compared with plain bearings, rolling bearings have the following advantages:

1. The friction coefficient of rolling bearings is smaller than that of sliding bearings, and the transmission efficiency is high. Generally, the friction coefficient of sliding bearings is 0.08-0.12, while the friction coefficient of rolling bearings is only 0.001-0.005;

2. Rolling bearings have been standardized, serialized and generalized, suitable for mass production and supply, and are very convenient to use and maintain;

3. Rolling bearings are made of bearing steel and subjected to heat treatment, so rolling bearings not only have high mechanical properties and long service life, but also can save the more expensive non-ferrous metals used in the manufacture of sliding bearings;

4. The internal clearance of the rolling bearing is very small, and the machining accuracy of each part is high, so the running accuracy is high. At the same time, the rigidity of the bearing can be increased by preloading. This is very important for precision machinery;

5. Some rolling bearings can bear radial load and axial load at the same time, so the structure of the bearing bearing can be simplified;

6. Due to the high transmission efficiency and low heat generation of rolling bearings, the consumption of lubricating oil can be reduced, and the lubrication and maintenance are more convenient;

7. Rolling bearings can be easily applied to uranium in any direction of space.

 

 

However, everything is divided into two, and rolling bearings also have certain disadvantages, the main ones are:

1. The load bearing capacity of rolling bearings is much smaller than that of sliding bearings of the same volume, therefore, the radial size of rolling bearings is large. Therefore, in the occasion of bearing large load and the occasion requiring small radial size and compact structure (such as internal combustion engine crankshaft bearing), sliding bearings are mostly used;

2. The vibration and noise of rolling bearings are large, especially in the later stage of use, therefore, when the precision requirements are very high and vibration is not allowed, rolling bearings are difficult to be competent, and the effect of sliding bearings is generally better;

3. Rolling bearings are particularly sensitive to foreign bodies such as metal chips, and once foreign objects enter the bearing, they will produce intermittent large vibration and noise, which will also cause early damage. In addition, rolling bearings are also susceptible to early damage due to metal inclusions. Even if early damage does not occur, there is a limit to the life of rolling bearings. In short, rolling bearings have a shorter service life than plain bearings.

 

Compared with rolling bearings and sliding bearings, each has its own advantages and disadvantages, and each occupies a certain applicable occasion, therefore, the two can not completely replace each other, and each develops in a certain direction and expands its own field. However, due to the outstanding advantages of rolling bearings, there is a tendency for latecomers to prevail. At present, rolling bearings have developed into the main support type of machinery, and are more and more widely used.