Characteristics, Differences and Applications of Common Bearings
Bearings are crucial components in mechanical equipment. Their main function is to support the mechanical rotating body, thereby reducing the coefficient of mechanical load friction during equipment transmission.
Bearings are classified according to the direction of load or nominal contact angle into radial bearings and thrust bearings.
According to the type of rolling elements, they are divided into ball bearings and roller bearings.
According to their self-aligning capability, they are classified into self-aligning bearings and non-self-aligning bearings (rigid bearings).
According to the number of rows of rolling elements, they are divided into single-row bearings, double-row bearings and multi-row bearings.
According to whether the components can be separated, they are divided into separable bearings and non-separable bearings.
In addition, there are classifications according to structural shape and size.
This article mainly shares the characteristics, differences and corresponding applications 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, and the smaller the contact angle, the more conducive to high-speed rotation. Single-row bearings can withstand radial loads and unidirectional axial loads. Structurally, two single-row angular contact ball bearings combined on the back share the inner and outer rings, and can withstand radial loads and bidirectional axial loads.

Main Applications:
- Single-row: Machine tool spindles, high-frequency motors, gas turbines, centrifugal separators, front wheels of small cars, differential pinion shafts.
- Double-row: Oil pumps, Roots blowers, air compressors, various transmissions, fuel injection pumps, printing machinery.
2. Self-aligning Ball Bearings
With double rows of steel balls and an inner spherical outer ring raceway, they can automatically adjust for shaft misalignment caused by deflection or misalignment of the shaft or housing. Tapered bore bearings can be easily mounted on the shaft using fasteners, mainly withstand radial loads.

Main Applications: Woodworking machinery, textile machinery drive shafts, vertical mounted self-aligning bearings.
3. Self-aligning Roller Bearings
This type of bearing has spherical rollers between the spherical raceway outer ring and the double raceway inner ring. According to different internal structures, it is divided into four types: R, RH, RHA and SR. Since the arc center of the outer ring raceway coincides with the bearing center, it has self-aligning performance, so it can automatically adjust for shaft misalignment caused by deflection or misalignment of the shaft or housing. It can withstand radial loads and bidirectional axial loads.

Main Applications: Paper machinery, reduction devices, railway vehicle axles, rolling mill gearbox seats, rolling mill roller paths, crushers, vibrating screens, printing machinery, woodworking machinery, various industrial reducers, vertical mounted self-aligning bearings.
4. Thrust Self-aligning Roller Bearings
The spherical rollers in this type of bearing are arranged obliquely. Due to the spherical shape of the raceway surface of the ring, it has self-aligning performance, so the shaft is allowed to have a certain degree of inclination. The axial load capacity is very large, and it can also withstand a certain radial load while withstand axial load. Generally, oil lubrication is used when in use.

Main Applications: Hydraulic generators, vertical motors, ship propeller shafts, rolling mill rolling screw reducers, tower cranes, coal mills, extruders, forming machines.
5. Tapered Roller Bearings
This type of bearing is equipped with conical rollers, which are guided by the large rib of the inner ring. The design makes the vertices of the conical surfaces of the inner ring raceway, outer ring raceway and roller rolling surface intersect at a point on the bearing centerline. Single-row bearings can withstand radial loads and unidirectional axial loads, while double-row bearings can withstand radial loads and bidirectional axial loads, and are suitable for withstand heavy loads and impact loads.

Main Applications: Automobiles: front wheels, rear wheels, transmissions, differential pinion shafts. Machine tool spindles, construction machinery, large agricultural machinery, railway vehicle gear reduction devices, rolling mill rolls and reduction devices.
6. Deep Groove Ball Bearings
Structurally, each ring of the deep groove ball bearing has a continuous groove-type raceway with a cross-section approximately one-third of the equatorial circumference of the ball. Deep groove ball bearings are mainly used to withstand radial loads, and can also withstand a certain axial load.
When the radial clearance of the bearing is increased, it has the characteristics of angular contact ball bearings and can withstand bidirectional alternating axial loads. Compared with other types of bearings of the same size, this type of bearing has a small friction coefficient, high limiting speed and high precision, and is the preferred bearing type for users when selecting.

Main Applications: Automobiles, tractors, machine tools, motors, water pumps, agricultural machinery, textile machinery, etc.
7. Thrust Ball Bearings
They are composed of washer-shaped raceway rings with raceways and ball and cage assemblies. The raceway ring that fits with the shaft is called the shaft ring, and the raceway ring that fits with the housing is called the seat ring. For double-directional bearings, the middle ring is fitted with the shaft. Single-directional bearings can withstand unidirectional axial loads, and double-directional bearings can withstand bidirectional axial loads (both cannot withstand radial loads).

Main Applications: Automobile steering knuckles, machine tool spindles.
8. Thrust Roller Bearings
Thrust roller bearings are used to withstand axial loads as the main axial-radial combined loads, but the radial load shall not exceed 55% of the axial load. Compared with other thrust roller bearings, this type of bearing has a lower friction coefficient, higher speed and self-aligning capability. The rollers of type 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 and many in number, so the load capacity is large. Generally, oil lubrication is adopted, and grease lubrication can be used in individual low-speed cases.

Main Applications: Hydraulic 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 guide ring form an assembly that can be separated from the other bearing ring, belonging to separable bearings.
This type of bearing is relatively convenient to install and disassemble, especially when the inner and outer rings and the shaft and housing are required to have an interference fit. This type of bearing is generally only used to withstand radial loads. Only single-row bearings with ribs on both the inner and outer rings can withstand small constant axial loads or large intermittent axial loads.

Main Applications: Large motors, machine tool spindles, axle boxes, diesel engine crankshafts, automobile and tractor gearboxes, etc.
10. Four-point Contact Ball Bearings
They can withstand radial loads and bidirectional axial loads. A single bearing can replace the front combination or back combination of angular contact ball bearings, and is suitable for withstand pure axial loads or composite loads with a large axial load component. When this type of bearing withstand axial loads in any direction, one of the contact angles can be formed, so the ring and the ball always contact at two points on any contact line.

Main Applications: Aircraft jet engines, gas turbines.
11. Thrust Cylindrical Roller Bearings
They are composed of washer-shaped raceway rings (shaft ring, seat ring) and cylindrical roller and cage assemblies. The cylindrical rollers are convexly machined, so the pressure distribution between the rollers and the raceway surface is uniform, and they can withstand unidirectional axial loads. The axial load capacity is large, and the axial rigidity is also strong.

Main Applications: Oil drilling rigs, iron and steel making machinery.
12. Thrust Needle Roller Bearings
The separable bearing is composed of a raceway ring and a needle roller and cage assembly, and can be arbitrarily combined with a thin raceway ring processed by stamping or a thick raceway ring processed by cutting. The non-separable bearing is an integral bearing composed of a raceway ring processed by precision stamping and a needle roller and cage assembly. It can withstand unidirectional axial loads. This type of bearing occupies a small space, which is conducive to the compact design of the machine. Most of them only use the needle roller and cage assembly, and use the installation surface of the shaft and the housing as the raceway surface.

Main Applications: Transmission devices of automobiles, cultivators, machine tools, etc.
13. Thrust Tapered Roller Bearings
This type of bearing is equipped with conical rollers (the large end is spherical), and the rollers are accurately guided by the ribs of the raceway ring (shaft ring, seat ring). The design makes the vertices of the conical surfaces of the shaft ring and seat ring raceways and the roller rolling surface intersect at a point on the bearing centerline. Single-directional bearings can withstand unidirectional axial loads, and double-directional bearings can withstand bidirectional axial loads.

Main Applications:
- Unidirectional: Crane hooks, oil drilling rig swivels.
- Bidirectional: Rolling mill rolls.
14. Insert Ball Bearings with Housings
Insert ball bearings with housings are composed of sealed insert ball bearings on both sides and cast (or steel plate stamped) bearing housings. The internal structure of the insert ball bearing is the same as that of the deep groove ball bearing, but the inner ring of this type of bearing is wider than the outer ring. The outer ring has a spherical outer surface that matches the concave spherical surface of the bearing housing to achieve automatic alignment.

Main Applications: Mining, metallurgy, agriculture, chemical industry, textile, printing and dyeing, conveying machinery, etc.