Compared to plain bearings, rolling bearings offer the following advantages:
1. Rolling bearings have been generalized, serialized and standardized, more suitable for mass production and supply, and are very convenient for use and maintenance;
2. The friction coefficient of rolling bearings is smaller than that of sliding bearings, and the transmission efficiency is higher and higher. The friction coefficient of plain bearings is generally 0.08-0.12, while the friction coefficient of rolling bearings is only 0.001-0.005;
3. The rolling bearing has high running accuracy, its internal clearance is very small, and the processing accuracy of each part is high. Rolling bearings can also increase the rigidity of the bearing by preloading the method. This is very important for precision mechanics;
4. Rolling bearings not only have high mechanical properties and long service life, rolling bearings are made of bearing steel, and after heat treatment, they can also save non-ferrous metals for the more expensive manufacture of sliding bearings;
5. Rolling bearings have high transmission efficiency, less calorific value, can reduce the consumption of lubricating oil, and lubrication maintenance is more convenient;
6. Some rolling bearings can bear axial load and radial load at the same time, which is conducive to simplifying the structure of the bearing support;
7. Rolling bearings can be easily applied to the shaft in any orientation of space.
Compared to plain bearings, rolling bearings also have the following disadvantages:
1. The ability of rolling bearings to bear loads is smaller than that of plain bearings of the same volume, so the radial size of rolling bearings is large. In the occasions where large loads need to be borne and small radial dimensions and compact structures are required (such as internal combustion engine crankshaft bearings), plain bearings are mostly used;
2. Rolling bearing vibration and noise are large, especially in the later stage of use, therefore, in the precision requirements are very high, no vibration is allowed, generally prefer to use sliding bearings;
3. Once a foreign body enters the rolling bearing, it will produce intermittent large vibration and noise, which will also cause early damage. In addition, rolling bearings are prone to early damage due to metal clamp impurities. Even if early damage does not occur, the life of rolling bearings is somewhat reduced. In general, rolling bearings have a shorter life than plain bearings.
Rolling bearings and sliding bearings have their own advantages and disadvantages, each occupies a certain applicability, the two can not completely replace each other, each to a certain direction of development. At present, rolling bearings have developed into the main support type of machinery, and are more and more widely used.
