Looking at the World of Bearings from Numbers

Sizes range from 2 millimeters to 6 meters

Bearings vary in size from small to large. The smallest "micro bearing" in the world has an inner diameter of 0.6mm × Outer diameter 2.0mm × Thickness 0.8mm, used for micro motors. And large bearings, with an outer diameter of 6 meters and a weight of over 15 tons, are used in large shield tunneling machines for excavating tunnels. This type of shield machine was used when excavating a cross sea tunnel under the Strait of Dover, which connects England and France, including the use of this large bearing.

400000 revolutions per minute

The dental drill (commonly known as dental phone) used by dentists is equipped with bearings that can rotate at ultra-high speeds. These are two inner diameter 3.0mm × Outer diameter 6.0mm × A high-precision bearing with a width of 2mm and a steel ball diameter of 1.0mm. They can rotate at an astonishing speed of "400000 revolutions per minute", greatly reducing the vibration of dental handpieces and greatly reducing the pain of patients during treatment.

Steel ball speed 160 meters per second

The V2500 jet engine of international airliners uses spindle bearings, with a rolling speed of 160 meters per second, equivalent to a speed of 580 kilometers per hour. It is precisely because of the use of high-performance high-speed bearings that the engine can operate safely for a long time and safely transport passengers to various parts of the world.

Amplitude below 100 nanometers

The accuracy of machinery depends on the rotational accuracy of bearings, which is no exaggeration. The two ends of the rotating shaft are supported by two bearings, and if the shaking of the shaft center is large, the mechanical performance cannot be improved. The WeChat official account of Mechanic Knowledge Network: share knowledge, spread value~the computer external storage equipment using ultra precision bearings, namely "hard disk", whose axis amplitude is less than 100 nm (1 nm=1/1000000 mm). The key to achieving such ultra-high accuracy is the accuracy of rolling elements such as "steel balls" and "rollers".

Can work in space for 15 years

The development of the universe also relies on bearings. Weather forecasts, satellite radio and television signals, and car satellite positioning information are all provided by artificial satellites flying around the Earth. The satellite is equipped with a gyroscope that maintains its attitude and heading, and the gyroscope is equipped with ultra precision bearings. This type of bearing can work continuously in space for 15 years.

A world from minus 253 degrees Celsius to minus 500 degrees Celsius

The bearings in the liquid fuel pump of a space rocket are the ones that use the lowest temperature. This type of bearing operates in liquid hydrogen at minus 253 ℃. The bearings used in high-temperature environments are typically represented by specialized high-performance bearings in medical CT scanners. In X-ray vacuum tubes with temperatures up to 300 to 500 ℃, bearings can also continue to operate, playing a role in ensuring our health.

Looking at the World of Bearings from the Perspective of Shape

Self aligning ball bearing

The self aligning roller bearing is equipped with a drum shaped roller between the inner ring with two raceways and the outer ring with a spherical raceway. The curvature center of the outer ring raceway surface is consistent with the center of the bearing, so it has the same centering function as automatic self-aligning ball bearings.

When the shaft and shell are bent, it can automatically adjust the load and axial load in both directions. Large radial load capacity, suitable for situations with heavy loads and shock loads. The inner diameter of the inner ring is a tapered hole bearing that can be directly installed. Alternatively, use a locking sleeve or disassembly cylinder to install it on the cylindrical shaft. The cage is made of steel plate stamped cage, polyamide formed cage, and copper alloy car made cage.

Needle bearing

Solid needle roller bearings

The basic structure of an inner ring bearing is the same as that of a NU cylindrical roller bearing, but due to the use of rolling needles, its volume can be reduced and it can withstand large radial loads. Without an inner ring bearing, the installation surface of the shaft with appropriate accuracy and hardness should be used as the raceway surface.

thrust needle bearing

Separated bearings are composed of raceways, needle rollers, and cage components, and can be combined with thin raceways (W) processed by stamping or thick raceways (WS) processed by cutting. Non separable bearings are integral bearings composed of precision stamped raceways, needle rollers, and cage components. This type of bearing can withstand unidirectional axial loads. Small footprint, conducive to compact mechanical design, mostly using only needle and cage components, and using the installation surface of the shaft and casing as the raceway surface.

Tapered Roller Bearing

This type of bearing is equipped with a circular frustum shaped roller, which is guided by the large retaining edge of the inner ring. In design, the vertices of the cone surfaces of the inner ring raceway surface, outer ring raceway surface, and roller rolling surface intersect at a point on the bearing centerline. Single row bearings can withstand radial and unidirectional axial loads, while double row bearings can withstand radial and bidirectional axial loads, suitable for bearing heavy and impact loads.

Cylindrical Roller Bearing

According to the number of rows of rolling elements used in bearings, cylindrical roller bearings can be divided into single row, double row, and multi row cylindrical roller bearings. One of the most commonly used is single row cylindrical roller bearings with cages. In addition, there are cylindrical roller bearings with other structures such as single or double row fully loaded rollers.

Single row cylindrical roller bearings are divided into N type, NU type, NJ type, NF type, and NUP type according to the different retaining edges of the ring. Cylindrical roller bearings have a large radial load capacity, and can also withstand certain unidirectional or bidirectional axial loads according to the structure of the ring guard. NN and NNU double row cylindrical roller bearings have a compact structure, strong rigidity, high load-bearing capacity, and small deformation after being loaded. They are mostly used for supporting machine tool spindles. FC, FCD, and FCDP four row cylindrical roller bearings can withstand large radial loads and are mostly used in heavy machinery such as rolling mills.

Self aligning roller bearing

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. Due to the alignment between the arc center of the outer ring raceway and the center of the bearing, it has the ability to automatically adjust the misalignment of the shaft caused by the bending or non concentricity of the shaft or shell. Can withstand radial and bidirectional axial loads. Especially with large radial load capacity, it is suitable for bearing heavy loads and impact loads.

Tapered hole bearings can be assembled and disassembled on the shaft by using fasteners or withdrawal sleeves. Self aligning roller bearings can withstand large radial loads and also certain axial loads. The outer ring raceway of this type of bearing is spherical, so it has centering performance. When the shaft is bent or tilted under force and the relative inclination between the inner ring centerline and the outer ring centerline does not exceed 1 ° to 2.5 °, the bearing can still work.

Thrust roller bearing

Thrust roller bearings include thrust self-aligning roller bearings, thrust cylindrical roller bearings, and thrust tapered roller bearings. Thrust self-aligning roller bearings can withstand both axial and radial loads, but the radial load must not exceed 55% of the axial load. Another important feature of this type of bearing is its automatic centering performance, which makes it less sensitive to different centricity and shaft deflection. As long as the loads P and P. If it does not exceed 0.05C and the shaft ring rotates, the bearing allows a certain range of centering angle. Small values are suitable for large bearings, and the allowable centering angle will decrease when the load increases.

Outer spherical bearing

Outer spherical bearings are preferred for applications that require simple equipment and components, such as agricultural machinery, transportation systems, or construction machinery.

Mainly used to withstand combined radial and axial loads mainly based on radial loads, it is generally not suitable to bear axial loads alone. This type of bearing can be installed with inner rings (with a complete set of rollers and retainers) and outer rings separately. This type of bearing does not allow the shaft to tilt relative to the casing, and will generate additional axial force under radial load. The size of the axial clearance of this type of bearing is closely related to its normal operation. When the axial clearance is too small, the temperature rise is relatively high; When the axial clearance is large, the bearing is prone to damage. Therefore, special attention should be paid to adjusting the axial clearance of the bearing during installation and operation. If necessary, pre interference installation can be used to increase the rigidity of the bearing.

Joint bearing

Joint bearings can be lubricated or self-lubricating. Joint bearings are a special type of sliding bearing with a special structure. Its structure is simpler than that of rolling bearings. It mainly consists of one outer ring with an inner spherical surface and can withstand large loads. Depending on the inner ring with an outer spherical surface and its different types and structures, it can withstand radial loads, axial loads, or combined loads that exist both radially and axially. It is generally used for swinging movements with lower speeds (i.e. angular motion, or tilting motion within a certain angle range (i.e. centering motion), as the sliding surface is spherical motion), and can still work normally when the support shaft and shaft shell hole are not concentric.

Linear bearing

Linear motion ball bearings are mainly used in the parts of mechanical equipment that move back and forth in a straight line, with advantages such as low friction, flexible movement, and convenient maintenance and replacement. It is widely used in fields such as textile machinery, printing machinery, pharmaceutical machinery, precision machine tools, electrical cutting machines, and automatic recorders.

Angular contact bearing

Angular contact ball bearings can withstand both radial and axial loads, as well as pure axial loads, with higher limit speeds. The ability of this type of bearing to withstand axial loads is determined by the contact angle, which is large and has a high ability to withstand axial loads.