The bearing is a component that fixes and reduces the friction coefficient of the load during the mechanical transmission process. It has an important position in contemporary machinery and equipment. Its main function is to support the mechanical rotating body to reduce the friction coefficient of the mechanical load during the transmission of the equipment. Bearings can be divided into rolling bearings and sliding bearings. Today we will talk about rolling bearings in detail.
Rolling bearing is a kind of precision mechanical component that changes the sliding friction between the running shaft and the shaft seat into rolling friction, thereby reducing friction loss. Rolling bearings are generally composed of four parts: inner ring, outer ring, rolling elements and cage. The function of the inner ring is to cooperate with the shaft and rotate with the shaft; the function of the outer ring is to cooperate with the bearing seat and play a supporting role; The cage evenly distributes the rolling elements between the inner ring and the outer ring, and its shape, size and quantity directly affect the performance and life of the rolling bearing; the cage can evenly distribute the rolling elements, prevent the rolling elements from falling off, and guide the rolling elements Rotation plays a role of lubrication.

Rolling bearing features
1. Specialization
In the processing of bearing parts, a large number of special bearing equipment are used. For example, ball mills, grinding machines and other equipment are used for steel ball processing. Specialization is also reflected in the production of bearing parts, such as a steel ball company specializing in the production of steel balls and a miniature bearing factory specializing in the production of miniature bearings.
2. Advanced
Due to the large-scale requirements of bearing production, it is possible to use advanced machine tools, tooling and technology. Such as CNC machine tools, three-jaw floating chucks and protective atmosphere heat treatment.
3. Automation
The specialization of bearing production provides conditions for its production automation. In production, a large number of fully automatic, semi-automatic dedicated and non-dedicated machine tools are used, and production automatic lines are gradually popularized and applied. Such as automatic heat treatment line and automatic assembly line.
According to the structure type, the rolling element and ring structure can be divided into: deep groove ball bearing, needle roller bearing, angular contact bearing, self-aligning ball bearing, self-aligning roller bearing, thrust ball bearing, thrust self-aligning roller bearing , Cylindrical roller bearings, tapered roller bearings, outer spherical ball bearings and so on.

According to the structure, rolling bearings can be divided into:
1. Deep groove ball bearings
Deep groove ball bearings are simple in structure and easy to use. They are a type of bearings with large production batches and a wide range of applications. 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. Used in automobiles, tractors, machine tools, motors, water pumps, agricultural machinery, textile machinery, etc.
2. Needle roller bearings
Needle roller bearings are equipped with thin and long rollers (the roller length 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 the same as other types of bearings. The outer diameter is small, and it is especially suitable for supporting structures with 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, in order to maintain the 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. For example: universal joint shafts, hydraulic pumps, sheet rolling mills, rock drills, machine tool gearboxes, automobile and tractor gearboxes, etc.
3. Angular contact bearings
Angular contact ball bearings have a high limit speed and can bear both longitudinal load and axial load, as well as pure axial load. The axial load capacity is determined by the contact angle and increases with the increase of the contact angle. Mostly used for: oil pumps, air compressors, various transmissions, fuel injection pumps, printing machinery.
4. Self-aligning ball bearing
The self-aligning ball bearing has two rows of steel balls, the inner ring has two raceways, and the outer ring raceway is an inner spherical surface, which has the performance of self-aligning. It can automatically compensate for the coaxiality error caused by the bending of the shaft and the deformation of the housing, and it is suitable for parts where strict coaxiality cannot be guaranteed in the support seat hole. The 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 steel balls is stressed. It is mainly used in agricultural machinery such as combine harvesters, blowers, paper machines, textile machinery, woodworking machinery, traveling wheels and drive shafts of bridge cranes.
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, especially suitable for working under heavy load or vibration load, but cannot bear pure axial load; it has good centering performance and can compensate the same bearing error. Main uses: papermaking machinery, reduction gears, railway vehicle axles, rolling mill gearbox seats, crushers, various industrial reducers, etc.
6. Thrust ball bearings
Thrust ball bearing is a separable bearing, the shaft ring “seat washer can be separated from the cage” steel ball components. 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 the shaft and the shaft. Thrust ball bearings can only be pumped
Hand axial load, one-way thrust ball bearing can only bear the axial load of one room, two-way thrust ball bearing can bear two
Axial load in all directions. The thrust ball can withstand the warp direction of the shaft that cannot be adjusted, and the limit speed is very low. One-way thrust ball bearing
The shaft and housing can be axially displaced in one direction, and the two-way bearing can be axially displaced in two directions. Mainly used in automobile steering mechanism and machine tool spindle.
7. Thrust roller bearing
Thrust roller bearings are used to withstand the combined longitudinal load of the shaft with the main axial 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 asymmetric spherical rollers, which can reduce the relative sliding of the stick and the raceway during work, and the rollers are long, large in diameter, and 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. When designing and selecting, it should be preferred. Mainly used in hydroelectric generators, crane hooks, etc.
8. 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 the other bearing ring and is a separable bearing. 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. Mainly used for large motors, machine tool spindles, axle boxes, diesel crankshafts and automobiles, etc.
9. Tapered roller bearings
Tapered roller bearings are mainly suitable for bearing combined radial and axial loads based on radial loads, while large cone angle cones
Roller bearings can be used to withstand the combined axial load, which is dominated by the 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. In the process of installation and use, the radial and axial clearance of the bearing can be adjusted. It can also be pre-interference installed for automobile rear axle hubs, large-scale machine tool spindles, high-power reducers, axle bearing boxes, and rollers for conveying devices. .
10. 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. Generally, 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 seated bearing has a compact structure.