Bearing: Features, Types and Uses

Bearings are important components in mechanical equipment. Its main function is to support the mechanical rotating body to reduce the friction coefficient of the mechanical load during the transmission process of the equipment.

Bearings are divided into radial bearings and thrust bearings according to the bearing direction or the nominal contact angle.

According to the type of rolling element, it is divided into ball bearing, roller bearing.

According to whether it is self-aligning, it is divided into self-aligning bearings, non-aligning bearings (rigid bearings).

According to the number of rows of rolling elements, it is divided into single-row bearings, double-row bearings, and multi-row bearings.

According to whether the parts can be separated, they are divided into separable bearings and non-separable bearings.

In addition, there are classifications by structure shape, and size.

This article mainly shares the characteristics, differences, and corresponding uses of 14 common bearings.

1. Angular contact ball bearings   

There is a contact angle between the ring and the ball. The standard contact angles are 15°, 30°, and 40°. The larger the contact angle, the greater the axial load capacity. The smaller the contact angle, the more conducive to high-speed rotation. Bear radial load and unidirectional axial load. The two single-row angular contact ball bearings that are combined in structure on the back share the inner ring and the outer ring and can bear radial load and bidirectional axial load.

Main uses: 

Single row: machine tool spindle, high-frequency motor, gas turbine, centrifugal separator, the front wheel of a small car, differential pinion shaft.

Double row: oil pump, roots blower, air compressor, various transmissions, fuel injection pump, printing machinery.

2. Self-aligning ball bearings 

Double-row steel balls, the outer ring raceway is an inner spherical type, so it can automatically adjust the shaft misalignment caused by the deflection or misalignment of the shaft or the casing. The tapered hole bearing can be easily installed on the shaft by using fasteners. bear radial loads.

Main uses: woodworking machinery, textile machinery transmission shaft, vertical self-aligning bearing with seat.

3. Spherical roller bearings

This type of bearing is equipped with spherical rollers between the outer ring of the spherical raceway and the inner ring of the double raceway. According to the different internal structures, it is divided into four types: R, RH, RHA, and SR. The center of the bearing is consistent and has self-aligning performance, so it can automatically adjust the misalignment of the shaft caused by the deflection or misalignment of the shaft or the casing and can withstand radial loads and bidirectional axial loads.

Main uses: papermaking machinery, reduction gear, railway vehicle axles, rolling mill gearbox seats, rolling mill rollers, crushers, vibrating screens, printing machinery, woodworking machinery, various industrial reducers, vertical self-aligning bearings with seats .

4. Thrust spherical roller bearings

In this type of bearing, the spherical rollers are arranged obliquely. Since the raceway surface of the raceway is spherical and has self-aligning performance, the shaft can be allowed to have some inclination, and the axial load capacity is very large. Radial load, oil lubrication is generally used when used.

Main uses: hydroelectric generators, vertical motors, propeller shafts for ships, reducers for rolling screws in rolling mills, tower cranes, coal mills, extruders, and forming machines.

5. Tapered roller bearings

This type of bearing is equipped with truncated rollers, which are guided by the large rib of the inner ring. The design makes the vertices of the inner ring raceway surface, the outer ring raceway surface, and the conical surfaces of the roller rolling surface intersect at the centerline of the bearing. point above. Single-row bearings can bear radial load and one-way axial load, and double-row bearings can bear radial load and two-way axial load and are suitable for bearing heavy load and impact load.

Main use: Automobile: front wheel, rear wheel, transmission, differential pinion shaft. Machine tool spindles, construction machinery, large agricultural machinery, gear reduction devices for railway vehicles, rolling mill roll necks, and reduction devices.

6. Deep groove ball bearings 

Structurally, each ring of a deep groove ball bearing has a continuous groove-type raceway with a cross-section of approximately one-third of the equatorial circumference of the ball. Deep groove ball bearings are mainly used to bear radial loads, and can also bear certain axial loads.

When the radial clearance of the bearing increases, it has the properties of an angular contact ball bearing and can bear axial loads alternating in two directions. Compared with other types of bearings of the same size, this type of bearing has a small friction coefficient, high limit speed, and high precision, and is the preferred bearing type for users when selecting models.

Main uses: automobiles, tractors, machine tools, motors, water pumps, agricultural machinery, textile machinery, etc.

7. Thrust ball bearings

It is composed of a washer-shaped raceway ring with a raceway, a ball, and a cage assembly. The raceway ring matched with the shaft is called a shaft washer, and the raceway ring matched with the housing is called a seat ring. The two-way bearing is matched with the secret shaft in the middle ring, the one-way bearing can bear a one-way axial load, and the two-way bearing can bear a two-way axial load (both can not bear radial load).

Main uses: automobile steering pin, machine tool spindle.

8. Thrust roller bearings 

Thrust roller bearings are used for shafts that mainly bear axial loads, and the meridional load is combined, but the meridional load shall not exceed 55% of the axial load. Compared with other thrust roller bearings.  this kind of bearing has a lower friction factor, higher speed, and self-aligning ability. The rollers of the 29000 bearings are asymmetric spherical rollers, which can reduce the relative sliding between the rollers and the raceway during operation, and the rollers are long, large in diameter, large in number of rollers, and large in load capacity. Oil lubrication is usually used. Grease lubrication is available for individual low-speed situations.

Main uses: hydroelectric generators, crane hooks.

9. Cylindrical roller bearings

The rollers of cylindrical roller bearings are usually guided by the two ribs of one bearing ring. The cage rollers and the guide ring form a combination, which can be separated from the other bearing ring, which is a separable bearing.

This kind of bearing is easy to install and disassemble, especially when the inner and outer rings are required to be interference fit with the shaft and the housing. Such bearings are generally only used to bear radial loads, and only single-row bearings with ribs on both the inner and outer rings can bear a small steady axial load or a large intermittent axial load.

Main uses: large motors, machine tool spindles, axle boxes, diesel engine crankshafts, automobiles, variable boxes that are kept in mind, etc.

10. Four-point contact ball bearings 

It can bear radial load and bidirectional axial load. A single bearing can replace the angular contact ball bearing with a front combination or rear combination. It is suitable for bearing pure axial load or synthetic load with large axial load components. This type of bearing can withstand any direction. One of the contact angles can be formed when the axial load of the ferrule is constant, so the ferrule and the ball are always in point contact with two sides and three knives on any contact line.

Main uses: aircraft jet engines, gas turbines.

11. Thrust cylindrical roller bearings

It consists of washer-shaped raceway rings (shaft washers, seat washers), cylindrical rollers, and cage assemblies. The cylindrical roller is processed with a convex surface, so the pressure distribution between the roller and the raceway surface is uniform, and it can bear a one-way axial load, with a large axial load capacity and strong axial rigidity.

Main uses: oil drilling rigs, iron, and steel making machinery.

12. Thrust needle roller bearings 

Separable bearings are composed of raceway rings, needle rollers, and cage assemblies, and can be combined arbitrarily with stamped thin raceway rings or cut and machined thick raceway rings. Non-separable bearings are integral bearings composed of precision stamped raceway rings, needle rollers, and cage assemblies, which can withstand unidirectional axial loads. This type of bearing occupies a small space and is conducive to the compact design of machinery. Only the needle roller and cage assembly are used, and the mounting surface of the shaft and housing is used as the raceway surface.

Main application: speed change device for automobiles, cultivators, machine tools, etc.

13. Thrust tapered roller bearings

This type of bearing is equipped with a truncated roller (the big end is a spherical surface), and the roller is accurately guided by the rib of the raceway ring (shaft washer, seat washer). The apex of each conical surface intersects at a point on the centerline of the bearing, the one-way bearing can bear a one-way axial load, and the two-way bearing can bear a two-way axial load.

Main uses: 

One-way: crane hook, oil rig swivel.

Bidirectional: rolling mill roll neck.

14. Outer spherical ball bearing with seat

The spherical insert ball bearing with a seat consists of an insert spherical ball bearing with seals on both sides and a cast (or steel plate stamped) 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, and the outer ring has a truncated spherical outer surface, which can be automatically aligned with the concave spherical surface of the bearing seat.

Main uses: mining, metallurgy, agriculture, chemical industry, textile, printing and dyeing. Conveying machinery, etc.