The use of bearings and the misunderstanding of the quality of the products at the time of purchase
First, the classification and use of bearings
1. Deep groove ball bearings The most representative rolling bearings are widely used. Can withstand radial loads and bidirectional axial loads. Suitable for high speed rotation and low noise and low vibration. Sealed bearings with steel dust caps or rubber seals are pre-filled with the right amount of grease, and the outer ring with snap ring or flanged bearings is easy to position axially and is easy to install inside the casing. The size of the maximum load bearing is the same as that of the standard bearing, but there is a loading groove in the inner and outer rings, which increases the number of balls loaded and improves the rated load. The main application is the cage and the steel stamping cage (waveform, crown shape...single row; S Shape...double column)
Copper alloy or phenolic resin cutting cage, synthetic resin forming cage.
The main purpose:
Automobiles: Rear wheels, transmissions, and electrical components. Electrical: General-purpose motors, household appliances. Others: instruments, internal combustion engines, construction machinery, railway vehicles, loading and unloading machinery, agricultural machinery, various industrial machinery.
2. There is a contact angle between the angular contact ball bearing ring and the ball. The standard contact angle is 15°, 30° and 40°. The larger the contact angle is, the larger the axial load capacity is. The smaller the contact angle is, the better it is. High speed rotation. Single row bearings can withstand radial loads and one-way axial loads. DB combination, DF combination and double row bearings can withstand radial loads and biaxial axial loads. DT combination is suitable for one-way axial loads and rated load for single bearings. Insufficient occasions. The high-speed ACH type bearing has small ball diameter and many ball numbers, and is mostly used for machine tool spindles. Angular contact ball bearings are suitable for high-speed and high-precision rotation. The two single-row angular contact ball bearings that are combined on the back side share the inner and outer rings. It can withstand radial loads and biaxial axial loads, and non-filled groove bearings are also sealed.
Mainly applicable cages: steel stamping cages (bowl shape...single row; S-shaped, crown-shaped...double row), copper alloy or phenolic resin cutting cage, synthetic resin forming cage.
The main purpose:
Single row: machine tool spindle, high frequency motor, gas turbine, centrifugal separator, small car front wheel, differential pinion shaft.
Double row: oil pump, Roots blower, air compressor, various transmissions, fuel injection pumps, printing machinery.
3. Four-point contact ball bearings can withstand radial loads and bidirectional axial loads. A single bearing can replace the angular contact ball bearing of the front combination or the back combination. Suitable for composite loads with a large axial load or large axial load component. This type of bearing can form one contact angle (α) when subjected to axial load in any direction, so the ferrule is always in contact with the ball. Two sides of the line are in contact with each other.
Mainly applicable cage: copper alloy cutting cage.
Main uses: aircraft jet engines, gas turbines.
4. Self-aligning ball bearing has spherical shape on the outer ring raceway surface and has self-aligning performance, so it can automatically adjust the shaft misalignment caused by the deflection or different center of the shaft or the outer casing. The tapered hole bearing can be conveniently used by using fasteners. Ground mounted on the shaft.
Steel stamping cage: daisy-shaped...12,13,22...2RS, 23...2RS, sunflower-shaped...22,23
Uses: woodworking machinery, textile machinery drive shaft, vertical with seated self-aligning bearings
5. Cylindrical roller bearing cylindrical roller is in line contact with the raceway. It has large radial load capacity, which is suitable for bearing heavy load and impact load. It is also suitable for high-speed rotation N-type and NU-type axial movement, which can adapt to the cause. The change of the relative position of the shaft and the casing caused by thermal expansion or installation error is most suitable for use as a free end bearing NJ type and NF type can withstand a certain degree of unidirectional axial load, NH type and NUP type can withstand a certain degree of bidirectional axial direction The inner ring or the outer ring of the load can be separated, which is easy to assemble and disassemble NNU type and NN type, and has strong rigidity against radial load, and is mostly used for machine tool spindles.
Mainly applicable cages: steel stamping cages (Z-shaped), copper alloy cutting cages, pin cages, synthetic resin forming cages.
Main uses: medium and large motors, generators, internal combustion engines, gas turbines, machine tool spindles, reduction gears, loading and unloading machinery, various industrial machinery.
6. The basic structure of the inner needle bearing of the solid needle roller bearing is the same as that of the NU type cylindrical roller bearing, but due to the use of the needle roller, the volume can be reduced, and the large radial load can be withstood without the inner ring bearing to have the appropriate precision and The mounting surface of the shaft of the hardness is used as a raceway surface.
Mainly applicable cage: steel stamping cage.
Main uses: automotive engines, transmissions, pumps, excavator track wheels, hoists, bridge cranes, compressors.
7. Tapered Roller Bearings This type of bearing is equipped with a truncated roller. The roller is guided by the large rib of the inner ring. The apexes of the conical surfaces of the inner ring raceway surface, the outer ring raceway surface, and the roller rolling surface are designed to intersect at a point on the bearing center line.
Single row bearings can withstand radial loads and one-way axial loads, and double row bearings can withstand radial loads and bidirectional axial loads.
It is suitable for bearing heavy load and impact load. According to the contact chest (α), it is divided into three types: small cone angle, middle cone angle and large cone angle. The larger the contact angle, the greater the axial load capacity. The outer ring and the inner component (the inner ring and the roller and the cage assembly) are separable for easy assembly and disassembly, and the bearings of the rear auxiliary code "J" or "JR" are internationally interchangeable. This type of bearing also uses the British series.
Mainly applicable cages: steel stamping cages, synthetic resin forming cages, pin cages.
Main use: 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 gears.
8. Spherical Roller Bearings This type of bearing is equipped with spherical rollers between the spherical raceway outer ring and the double raceway inner ring. According to the internal structure, it is divided into four types: R, RH, RHA and SR. The center of the arc of the raceway is consistent with the center of the bearing and has self-aligning properties, so the shaft misalignment caused by the deflection or misalignment of the shaft or the casing can be automatically adjusted. Can withstand radial loads and bidirectional axial loads. Especially the radial load capacity is large, suitable for bearing heavy loads and impact loads.
9. The tapered bore bearing can be assembled and disassembled on the shaft by using fasteners or withdrawal sleeves.
There are two types of tapered holes (taper):
1:30 (auxiliary code: K30) ... applies to the 240, 241 series.
1:12 (auxiliary code: K).........Applicable to other series.
Oil holes, oil grooves and positioning pin holes (one) can be provided on the outer ring. Oil holes and oil grooves can also be provided on the inner ring.
Mainly applicable cages: copper alloy cutting cages, steel stamping cages, pin cages, synthetic resin forming cages.
Main uses: paper machine, speed reducer, railway vehicle axle, rolling mill gear box seat, rolling mill roller table, crusher, vibrating screen, printing machinery, woodworking machinery, various industrial speed reducers, vertical belt seated self-aligning bearings .
10. Thrust ball bearings consist of a washer-shaped raceway with a raceway and a ball and cage assembly. The raceway ring that cooperates with the shaft is called a shaft ring, and the raceway ring that cooperates with the outer casing is called a raceway. The two-way bearing will match the middle ring, the one-way bearing can bear the one-way axial load, and the two-way bearing can bear the two-way axial load (both can not bear the radial load).
Mainly applicable cages: steel stamping cages, copper alloy or phenolic resin cutting cages, synthetic resin forming cages.
Main uses: car steering pin, machine tool spindle.
11. Thrust cylindrical roller bearing It consists of a washer-shaped raceway ring (shaft ring, race) and a cylindrical roller and cage assembly. The cylindrical roller is processed by convex surface, so the pressure distribution between the roller and the raceway surface is uniform, and it can withstand one-way axial load, and the axial load capacity is large, and the axial rigidity is also strong.
Mainly applicable cage: copper alloy cutting cage Main use: oil drilling machine, iron making steel machinery
12. Thrust needle roller bearing The split type bearing is composed of a raceway ring and a needle roller and a cage assembly, and can be combined with a thin rolling ring (W) for press working or a thick raceway ring (WS) for cutting. Non-separable bearings are one-piece axial loads that are formed by precision stamped raceway rings and needle and cage assemblies. This type of bearing occupies a small space, which is conducive to the mechanical compact design. Most of them use only the needle roller and the cage assembly, and the mounting surface of the shaft and the outer casing is used as the raceway surface.
Mainly applicable cage: steel stamping and holding, synthetic resin forming cage.
Main uses: shifting devices for automobiles, cultivators, machine tools, etc.
13. Thrust tapered roller bearing This type of bearing is equipped with a circular table-shaped roller (the large end is a spherical surface). The roller is accurately guided by the rim of the raceway ring (shaft ring, seat ring), and the design is such that the shaft ring and the race ring are rolled. The vertices of the facets and the conical faces of the rolling surfaces of the rollers intersect at a point on the centerline of the bearing. One-way bearings can withstand one-way axial loads and two-way bearings can withstand two-way axial loads. The two-way bearing cooperates with the middle ring and the shaft, but because of the clearance fit, it is necessary to use the bushing or the like to axially position the middle ring. The main suitable cage: copper alloy cutting cage.
Main use: one-way: crane hook, oil rig swivel;
Two-way: Roller neck.
14. Thrust spherical roller bearing The spherical roller of this type of bearing is arranged obliquely. Because the raceway surface of the raceway is spherical and has self-aligning performance, it can allow the axle to have some inclination, and the axial load capacity is very large. It can also bear a number of radial loads while being loaded, and is generally oil lubricated when used.
Mainly applicable cage: copper alloy cutting cage.
Main uses: hydroelectric generators, vertical motors, propeller shafts for ships, reducers for rolling mill rolling screws, tower cranes, coal mills, extruders, forming machines.
Second, several misunderstandings when testing quality at the time of purchase
1. Through the surface feeling bearing quality In the process of selling bearings, many customers said that as long as the bearing surface is bright, the quality is good, which is wrong. The brightness of the bearing surface should be bright, and the reason for this blackness is that the steel used in the bearing is up to standard and its grinding process and cutting fluid used, etc., the former two are the main ones.
2, whether the chamfer is bright The chamfer of the bearing does not determine the quality of the bearing, but it reflects the processing method of the bearing. The chamfer is black, indicating that heat treatment such as quenching increases the hardness of the bearing, and some people think that the chamfer is black and it is not processed completely. This is a misunderstanding.
3, the integrated cage is better than the two bodies, although the new process uses an integrated cage, but it only saves the material, and the performance of the rotation is worse than the two.
In general, the service life of the bearing is related to three factors, one is the quality of the bearing itself. The second is the use of the environment. The third is the installation method.
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