What are bearings?

wallpapers Industry 2020-10-26
The components that support the relatively rotating shaft are called bearings. Normally, the shaft rotates. There are also those in which the shaft does not rotate but the shell rotates, such as automobile wheel hub bearings.
Bearings are divided into rolling bearings and sliding bearings. The rolling bearings mentioned upstairs are only a general term for a class of bearings. There are generally the following ten types:
1. Deep groove ball bearings. Deep groove ball bearings are simple in structure and easy to use. They are the largest production batch , The widest application range of bearings. It is mainly used to bear radial load, but also can bear certain axial load. When the radial clearance of the bearing is enlarged, it has the function of angular contact bearing and can bear larger axial load.
2. Self-aligning ball bearing There are two rows of self-aligning ball bearings, the inner ring has two raceways, and the outer ring raceway is inner spherical, which has the performance of self-aligning. It can automatically compensate the coaxiality error caused by the bending of the shaft and the deformation of the housing, and it is suitable for parts where the support seat hole cannot guarantee strict coaxiality. This middle bearing mainly bears radial load. While bearing radial load, it can also bear a small amount of axial load. It is usually not used for bearing pure axial load. For example, bearing pure axial load, only one row of rigid balls is stressed.
3. Angular contact ball bearings Angular contact ball bearings have a high limit speed, which can bear both longitudinal load and axial load, or pure axial load. The axial load capacity is determined by the contact angle and increases with the contact angle And increase.
4. Cylindrical roller bearings The rollers of cylindrical roller bearings are usually guided by the two ribs of a bearing ring. The cage, the roller and the guide ring form an assembly, which can be separated from another bearing ring. Separable bearings. This kind of bearing is more convenient to install and disassemble, especially when the inner and outer ring and the shaft and the shell are required to be interference fit. This type of bearing is generally only used to bear radial load. Only single row bearings with ribs on the inner and outer rings can bear small steady axial loads or large intermittent axial loads.
5. Spherical Roller Bearings Spherical roller bearings have two rows of rollers, which are mainly used to bear radial loads and can also bear axial loads in any direction. This kind of bearing has high radial load capacity and is especially suitable for working under heavy load or vibration load, but it cannot bear pure axial load; it has good centering performance and can compensate the same bearing error.
6. Tapered roller bearings Tapered roller bearings are mainly suitable for bearing combined radial and axial loads based on radial loads, while large cone angle tapered roller bearings can be used for bearing diameters based on axial loads. Combined axial load. This type of bearing is a separable bearing, and its inner ring (including tapered rollers and cage) and outer ring can be installed separately. The radial clearance and axial clearance of the bearing can be adjusted during installation and use, and it can also be installed with pre-interference.
7. Thrust ball bearing Thrust ball bearing is a separable bearing. The shaft ring's seat ring can be separated from the cage's rigid ball component. The shaft ring is a ferrule matched with the shaft, and the seat ring is a ferrule matched with the bearing seat hole, and there is a gap between it and the shaft. Thrust ball bearings can only handle axial loads, one-way thrust ball bearings can only bear axial loads in one room, and two-way thrust ball bearings can bear axial loads in two directions. The thrust ball cannot limit the longitudinal movement of the shaft, and the limit speed is very low. The one-way thrust ball bearing can limit the axial displacement of the shaft and the housing in one direction, and the double-direction bearing can limit the axial displacement in two directions.
8. Thrust Roller Bearings Thrust spherical roller bearings are used to bear the main axial load of the shaft. The combined longitudinal load, but the longitudinal load shall not exceed 55% of the axial load. Compared with other thrust roller bearings, this type of bearing has a lower friction factor, higher speed, and has the ability to adjust the center. The rollers of type 29000 bearings are asymmetrical spherical rollers, which can reduce the relative sliding of the stick and raceway in the work, and the rollers are long and large in diameter, the number of rollers is large, and the load capacity is large. They are usually lubricated by oil. Grease lubrication can be used at low speeds. In the design and selection, it should be preferred.
9. Needle roller bearings Needle roller bearings are equipped with thin and long rollers (the length of the roller is 3-10 times the diameter, and the diameter is generally not greater than 5mm), so the radial structure is compact, and its inner diameter and load capacity are comparable to other types When the bearings are the same, the outer diameter is the smallest, which is especially suitable for supporting structures with limited radial installation dimensions. According to different applications, bearings without inner ring or needle roller and cage components can be selected. At this time, the journal surface and shell hole surface matching the bearing are directly used as the inner and outer rolling surfaces of the bearing to maintain load capacity and running performance Same as the bearing with ring, the hardness of the surface of the shaft or housing hole raceway. The machining accuracy and surface and surface quality should be similar to the raceway of the bearing ring. This kind of bearing can only bear radial load. 10. Outer spherical ball bearing with seat The outer spherical ball bearing with seat consists of an outer spherical ball bearing with seals on both sides and a cast (or stamped steel plate) bearing seat. The internal structure of the outer spherical ball bearing is the same as that of the deep groove ball bearing, but the inner ring of this kind of bearing is wider than the outer ring. The outer ring has a truncated spherical outer surface, which can automatically adjust the center when matched with the concave spherical surface of the bearing seat. Usually there is a gap between the inner hole of this kind of bearing and the shaft, and the inner ring of the bearing is fixed on the shaft with a jack wire, an eccentric sleeve or an adapter sleeve, and rotates with the shaft. The bearing with seat has compact structure, convenient loading and unloading, perfect sealing, suitable for simple support, and often used in mining, metallurgy, agriculture, chemical industry, textile, printing and dyeing, conveying machinery, etc.