Several common methods for identifying the quality of a bearing

The bearing model generally has a pre-code, a basic code and a post-code. In general, the bearing designation is only indicated by the basic designation. The basic model generally consists of three parts, the type code, the size code and the inner diameter code.

The post-code is to use letters and numbers to indicate the structure, tolerance and special requirements of the material. The prefix code is used to indicate the sub-components of the bearing, which are indicated by letters. General Purpose Bearing (Rolling Bearing) Designation Method.

The three elements of the method of identifying the quality of miniature bearings are as follows:

1.See. Observe the processing surface of the miniature bearing, the surface of the inferior miniature bearing is rough and the chamfer is uneven. The surface of high-quality miniature bearings is delicate and smooth, and the chamfer is uniform.

2.Turn. One hand holds the inner ring of the miniature bearing, and the other hand rotates the outer ring of the miniature bearing, and the inferior miniature bearing can feel the presence of foreign matter in the miniature bearing groove when rotating, and the selection is not smooth.

The high-quality miniature bearings rotate smoothly and smoothly without a sense of obstruction.

3.Listen. When the miniature bearing is running, the inferior miniature bearing has a "click" friction sound, and the high-quality miniature bearing does not exist The selection of the miniature bearing configuration mode Usually, the shaft is supported by two miniature bearings in the radial and axial directions, at this time, the miniature bearing on one side is called the fixed side miniature bearing, which bears two kinds of radial and axial loads, and plays the role of relative axial displacement between the fixed shaft and the miniature bearing box.

The other side is called the free side, and only the radial load is subjected, and the axial direction can be moved relative to each other, so as to solve the problem of the expansion and contraction part of the shaft due to temperature changes and the spacing error of the mounting miniature bearing.

For fixed-side miniature bearings, it is necessary to select miniature bearings that can be moved axially with a rolling surface (e.g., cylindrical roller miniature bearings) or with an assembly surface (e.g., radial ball miniature bearings). On relatively short shafts, where the fixed side is not much different from the free side, miniature bearings (e.g., radial thrust ball miniature bearings) that move in a fixed axial direction only in one direction are used.

First of all, look at the material used in the bearing steel.

Observational method. Observe the rolling bearing with the naked eye, the inner and outer raceways should have no peeling marks and serious wear, and be in the shape of an arc groove; All rolling elements should be free of spots, cracks and peeling on the surface; The cage should not be loose, undamaged, unworn through, and the gap between it and the rolling elements should not be too large.

Feel the method. The clearance between the inner and outer racepieces and the rolling elements of a normal bearing is millimeters. For rolling bearings that have been used for one stage, there should be no obvious noise when pinching the inner seat ring with your fingers for axial rocking.

Rotation method. Clamp the inner racer with one hand and rotate the outer racer with the other, the bearing should be able to rotate flexibly and radial shaking should not be felt.

Of course, it depends on ****, if it is much lower than normal, it may be fake, it is recommended not to buy, after all, you get what you pay for, after all, the cost is high, so the import is very expensive.

If you still don't understand, you can ask!

How to distinguish the real from the fake

1. Whether the steel seal is clear.

Each bearing product will be printed with its brand words, labels, etc. on the bearing product body. Although the font is very small, the products produced by regular manufacturers are printed with steel printing technology, and the font is pressed before heat treatment, so although the font is small, it is deep and very clear. Normally, the font of counterfeit products is not only blurry, but also floating on the surface due to the rough printing technology, and some can even be easily erased by hand or have serious manual marks.

2. Whether there is noise.

Hold the inner sleeve of the bearing with the left hand, and rotate the outer sleeve with a small reciprocating amount with the right hand to listen to whether there is any noise during the operation of the bearing. Due to the backward production conditions of most counterfeit products and the complete manual workshop operation, it is inevitable that impurities such as dust and sand will be mixed into the bearing body during the production process, so there will be noise or poor operation when the bearing rotates. This point is the key to judge whether a product comes from a brand product of a regular maker which has a strict production standard and operates with a machine.

3. Whether there are turbid oil stains on the surface.

Whether there are turbid oil stains on the surface, which requires us to pay special attention when buying imported bearings. Because there is still a certain gap between the domestic anti-rust technology and foreign advanced manufacturing countries, it is easy to leave a thick oil stain when the bearing body is treated with anti-rust, and it feels sticky and thick when touched by hand, while there is almost no trace of anti-rust oil on the bearing imported from abroad. According to industry insiders, particularly careful people can smell a special smell on imported bearings, which is the smell of anti-rust oil.

4. Whether the chamfer is uniform.

The so-called chamfer of the bearing, that is, the junction of the horizontal plane and the vertical surface, the counterfeit bearing products due to the limitations of production technology, in these corners and corners of the parts are not satisfactory, which we can easily identify.

5. Bearing packaging.

After the inner packaging and outer packaging bearings are manufactured and inspected, they are cleaned and anti-rust treatment, and then put into the inner packaging to achieve waterproof, moisture-proof, dust-proof, impact-proof, maintenance of the quality and accuracy of the bearings, as well as the purpose of convenient use and sales.

The inner packaging of the bearing is divided into three categories according to the anti-rust period:

Short anti-rust period packaging: anti-rust period of 3 to 6 months, suitable for large quantities of shipments to the same subscriber, short-term put into use bearings. By agreement between the two parties, simple packaging is adopted for the principle of convenience of use.

General anti-rust period packaging: anti-rust period of one year, suitable for general purpose bearings.

Long anti-rust period packaging: two years anti-rust period, suitable for special and precision bearings.

The inner packaging materials of the bearing include polyethylene plastic cylinder (box), kraft paper, plain and wrinkled polyethylene composite paper, paper box, polyethylene or polyethylene plastic film, nylon fastening tape or plastic braided fastening tape, waterproof and high-strength plastic tape, burlap bag, etc. The above materials need to ensure that the corrosion resistance test of the material is qualified.

The role of the bearing is to put it bluntly, if the transmission parts (such as: shaft) and the hole are directly matched, one is the transmission resistance is large, and the other is not easy to replace the transmission parts after the wear is large, and the bearing is dependent on the rolling contact between the elements to support the transmission parts, so the sliding resistance is small, the power consumption is less, and the starting is easy.

The main function of the bearing is to support the mechanical rotating body, reduce the friction coefficient during its movement, and ensure its rotation accuracy. It can be understood that it is used to fix the shaft so that it can only realize rotation, and control its axial and radial movement. If the shaft does not have bearings, it will not work at all.

Because the shaft can move in any direction, the shaft is required to rotate only when working.

Bearings are used in a wide range of applications, automobiles: rear wheels, transmission trouser height, electrical device components. Electrical:

General motors, household appliances. Instruments, internal combustion engines, construction machinery, railway vehicles, loading and unloading machinery, various industrial machinery. Machine tool spindles, agricultural machinery, high-frequency motors, gas turbines, centrifugal separators, front wheels of small cars, differential pinion shafts.

Oil pumps, roots blowers, air compressors, various transmissions, fuel injection pumps, printing machinery, electric motors, generators, internal combustion engines, gas turbines, machine tool spindles, deceleration devices, loading and unloading machinery, various industrial machinery, etc. Almost as long as it is rotating, bearings are used.

1. It is necessary to carefully investigate and record the dismantled bearing and appearance, in order to find out and investigate the remaining amount of lubricant, after sampling, the bearing should be cleaned well.

2. Secondly, check whether there is any damage and abnormality such as the condition of the raceway surface, the rolling surface and the mating surface, as well as the wear state of the cage.

3. To judge whether the bearing can be closed again, it is necessary to consider the degree of bearing damage, machine performance, importance, operating conditions, inspection cycle, etc.

4. If the bearing is found to be damaged or abnormal, the content of the injury section will find out the cause and formulate countermeasures. In addition, if there are any of the following defects, the bearing can no longer be used, and a new bearing needs to be replaced.