The characteristics, differences and uses of fourteen types of bearings in motors

Bearings are pivotal parts 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 of the equipment.

 

Bearings are divided into radial bearings and thrust bearings according to different bearing directions or nominal contact angles.

 

According to the types of rolling elements, they are divided into: ball bearings and roller bearings.

 

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

 

According to the number of rows of rolling elements, they are divided into single row bearings, double row bearings, and multiple row bearings.

 

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

 

In addition, there are classifications according to structure shape and size.

 

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

 

1 Angular contact ball bearing

 

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. Single row bearings can Withstand radial load and unidirectional axial load. The two single-row angular contact ball bearings combined on the back of the structure share an inner ring and an outer ring, which can bear radial load and bidirectional axial load.

 

 

Main motors used: DC motors, AC motors, synchronous motors, servo motors, etc.

 

Main uses of angular contact ball bearings:

 

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

 

Double rows: oil pumps, roots blowers, air compressors, various transmissions, fuel injection pumps, printing machinery.

 

2 Self-aligning ball bearing

 

Double-row steel balls, the outer ring raceway is an inner spherical surface, so it can automatically adjust the axis misalignment caused by the deflection or misalignment of the shaft or housing. The tapered bore bearing can be easily installed on the shaft through the use of fasteners. Withstand radial load.

 

 

Self-aligning ball bearing

 

Main uses: woodworking machinery, textile machinery drive 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 difference of the internal structure, it is divided into four types: R, RH, RHA and SR. The center of the bearing is consistent, with self-aligning performance, so it can automatically adjust the shaft center error caused by the deflection or misalignment of the shaft or housing, and can withstand radial load and bidirectional axial load.

 

 

Main uses of spherical roller bearings:

 

Papermaking machinery, reduction gears, railway vehicle axles, rolling mill gearbox seats, rolling mill roller tables, 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. Because the raceway surface of the raceway is spherical and has self-aligning performance, it can allow the shaft to have a certain degree of inclination, and the axial load capacity is very large. It can also bear several Radial load, oil lubrication is generally used when in use.

 

 

Main uses of thrust spherical roller bearings:

 

Hydroelectric generators, vertical motors, propeller shafts for ships, reducers for rolling screws of rolling mills, tower cranes, coal mills, extruders, and forming machines.

 

5 Tapered roller bearings

This type of bearing is equipped with truncated cone-shaped rollers, the rollers are guided by the large rib of the inner ring, and the design makes the vertices of the inner ring raceway surface, the outer ring raceway surface and the conical surface of the roller rolling surface intersect the center line of the bearing On the point. Single-row bearings can bear radial loads and unidirectional axial loads, and double-row bearings can bear radial loads and bidirectional axial loads, and are suitable for bearing heavy loads and shock loads.

 

The main purpose of tapered roller bearings:

 

Automobile: front wheel, rear wheel, transmission, differential pinion shaft. Machine tool spindles, construction machinery, large agricultural machinery, railway vehicle gear reduction devices, 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 raceway with a cross section about one-third of the circumference of the ball's equatorial circumference. Deep groove ball bearings are mainly used to bear radial load, but also can bear certain axial load.

 

When the radial clearance of the bearing increases, it has the properties of an angular contact ball bearing and can withstand alternating axial loads 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 accuracy. It is the preferred bearing type for users when selecting models.

 

The main purpose of deep groove ball bearings:

 

Automobiles, tractors, machine tools, motors, water pumps, agricultural machinery, textile machinery, etc.

 

7 Thrust ball bearings

 

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

 

The main purpose of thrust ball bearings: automobile steering pins, machine tool spindles.

 

8 Thrust roller bearing

 

Thrust roller bearings are used to bear the main axial load of the shaft, 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 during 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.

 

The main purpose of thrust roller bearings: hydroelectric generators, crane hooks.

 

9 Cylindrical roller bearings

 

The rollers of cylindrical roller bearings are usually guided by the two ribs of a bearing ring. The cage 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 rings, 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.

 

The main purpose of cylindrical roller bearings: large motors, machine tool spindles, axle boxes, diesel engine crankshafts, automobiles, gearboxes to keep in mind, etc.

 

10 Four-point contact ball bearing

 

It can bear radial load and two-way axial load. A single bearing can replace the angular contact ball bearing combined on the front or back. It is suitable for bearing pure axial load or synthetic load with large axial load component. This type of bearing can bear any direction One of the contact angles can be formed under the axial load, so the ferrule and the ball are always in contact with three points on both sides of any contact line.

 

 

Four-point contact ball bearings are mainly used: aircraft jet engines and gas turbines.

 

11 Thrust cylindrical roller bearing

 

It is composed of washer-shaped raceway ring (shaft washer, seat washer), cylindrical roller and cage assembly. Cylindrical rollers are processed on a convex surface, so the pressure distribution between the roller and the raceway surface is even, and it can withstand one-way axial load, the axial load capacity is large, and the axial rigidity is also strong.

 

The main purpose of thrust cylindrical roller bearings: oil drilling rigs, iron and steel making machinery.

 

12 Thrust needle roller bearings

 

Separate bearings are composed of raceway rings, needle rollers and cage components, and can be combined arbitrarily with stamped thin raceway rings or cut thick raceway rings. Non-separable bearings are integral bearings composed of raceway rings, needle rollers, and cage components that are processed by precision stamping. They can withstand one-way axial loads. This type of bearing occupies a small space and is conducive to the compact design of the machine. Only needle roller and cage components are used, and the mounting surface of the shaft and housing is used as the raceway surface.

 

The main purpose of thrust needle roller bearings: transmission devices for automobiles, tillers, machine tools, etc.

 

13 Thrust tapered roller bearings

 

Class bearings are equipped with truncated cone-shaped rollers (the big end is a spherical surface), and the rollers are accurately guided by the ribs of the raceway ring (shaft washer, seat ring). The apex of each conical surface intersects at a point on the center line of the bearing. One-way bearings can bear one-way axial loads, and two-way bearings can bear two-way axial loads.

 

The main purpose of thrust tapered roller bearings:

 

One-way: crane hook, oil rig swivel.

 

Two-way: Rolling mill roll neck.

 

14 Spherical ball bearing with seat

 

The outer spherical ball bearing with seat is composed of a sealed outer spherical ball bearing 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, and 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.

 

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