Common Methods To Identify FAG Bearing Quality

Writer: Eric Bearing Limited

Since Mr. Fischer of Germany invented the ball mill for grinding steel balls and founded FAG in 1883 , with the birth and development of the rolling bearing industry, FAG bearing products have been fully certified in almost all possible fields and have been playing With a very important role of FAG bearings. Only the main application areas of some of its products are listed below: aeronautical engineering, metal cutting machine tools, steel processing equipment, converters, casting equipment, rolling mills, mechanical transmission equipment, papermaking machinery, cement machinery, mills, mining machinery, construction machinery and vibration Machinery, environmental protection equipment, wind power generation equipment, ships, antennas and radar, textile machinery, packaging machinery, etc. 

Although the quality of FAG bearings is good, they still need to be checked during use. The best imported bearings in the world will also have problems. Therefore, we must check the situation during use and find that FAG imported bearings that are damaging quickly will be replaced immediately. New, so as not to cause major accidents.

During the inspection, you should check the FAG bearing vibration value changes, abnormal noise generation, temperature rise, lubricant dosage and properties changes; check the drive electromechanical current value changes to see if it may be normal. If there is an exception, it should be dealt with accordingly.

The use of FAG bearings in automobiles is very common, whether it is wheels, turntables, or other parts that need to be twisted, there are FAG bearings, which are very important instrument components in the transmission system. Due to the large amount of FAG used, its wear level is correspondingly high, so replacing FAG bearings is a common task in automobile maintenance. 

Whether the outer packaging of the bearing is clear

In general, the Zhengchang brand has its own special designer to design the external packaging, and arrange the production premises to pass the production premises for manufacturing. Therefore, the packaging is very clear from the line to the color block, without any blur. (There is also a joint design on the accessories packaging of some brands that is specifically used to maintain my common sense property rights, which will be introduced successively in the following content).

Whether the steel stamp of the bearing is clear

Brand words, labels, etc. will be printed on the FAG bearing body. The font is very small. Most of the products produced in the factory use steel stamping skills and are pressed before being processed by heat. Therefore, the font is small, but it is deep and very clear. The fonts of counterfeit products are not only trance, because the printing skills are rude, and the fonts are floating, and some can even be erased by hand.

Check the bearing for noise

Hold the FAG bearing inner sleeve with your left hand , and twist the outer garment to twist it with your right hand to hear whether there is any noise. Because the production of most counterfeit products is prematurely left behind, completely manual task-style operation, in the production process will inevitably be mixed with sand and other impurities, hidden in the FAG bearing body, so when it is reversed, it will announce a noise. This is the biggest disagreement with the authentic factory brand that strictly enforces production specifications and operates with machinery. ERIC BEARING LTD have enough stock for FAG 6204-2RSR bearings , pls click here :

Check the bearing surface for turbid oil

When buying FAG bearings, you should pay special attention to oil marks, because the current domestic anti-rust skills are not special, so it is easy to leave thick oil marks on the FAG bearing body when it is anti-rust treatment, which is sticky on the hand. It's thick, and the original FAG bearings in foreign countries can't see the antirust oil, but it is special and careful. The FAG bearing smells a bit. It must be the antirust oil, but it can't be seen.

Check whether the chamfer of the bearing is even

The chamfer of the FAG bearing is the intersection of the horizontal and vertical surfaces. Because of the limitations of production skills , the counterfeit FAG bearings feel that they are not enough in these corners. 

Vibration acceleration national standard (commonly known as Z standard)

1. The standard was established relatively early to measure the vibration acceleration value when the bearing rotates to determine the quality level of the bearing, which is divided into three quality levels from Z1 , Z2 and Z3 from low to high. At present, domestic bearing manufacturers are still using it. The vibration acceleration value is used to measure the quality of the bearing, which simply reflects the fatigue life of the bearing.

2. Vibration speed standard (commonly known as V standard)

Since the original vibration acceleration standard has not been abolished, the standard appeared as a standard issued by the Ministry of Machinery Industry. It was formulated with reference to European standards in combination with China ’s actual conditions and needs, and the quality level of bearings was divided by detecting the vibration speed of the bearings (equivalent to the national standard). It is divided into five quality levels : V , V1 , V2 , V3 , and V4 . The quality grades of various ball bearings are V , V1 , V2 , V3 , V4 from low to high; the quality grades of roller bearings (cylindrical, conical) are V , V1 , V2 , V3 from low to high . It reflects the quality of the bearing by detecting the vibration speed of the bearing at different frequencies (low frequency, intermediate frequency, high frequency). It can be roughly analyzed whether the bearing has geometric problems ( such as the ellipse of the steel ring ) , the quality problems of the raceway / rolling body, and the quality problems of the cage , which is significantly improved than the vibration acceleration to investigate the quality of the bearing. At present, domestic bearings exported to Europe, the Chinese military and the aerospace industry all carry out bearing quality testing in accordance with this standard. At the same time, testing the quality of imported bearings in Europe and identifying counterfeit imported bearings provide a viable means.

At present, there are two standards in parallel for bearing quality testing, and bearings with a high " Z standard" quality rating may not have good quality performance when tested with " V standard", and there is no correspondence between the two. This should be paid special attention to in the quality inspection of bearings. 

Vibration measuring instrument to detect the bearing in use

During the operation of the bearing, although the ISO2372 standard judges whether the vibration exceeds the standard by the vibration speed, in the field practice, special attention should be paid to the change of the acceleration value of the bearing. The damage process of the bearing is mostly manifested as fatigue damage at the initial stage, which can generally be expressed as The obvious acceleration increases, with the development of fatigue, the vibration speed and displacement gradually increase, indicating that the bearing has fatigue failure. Especially when testing the bearing, pay attention to whether the vibration value is oscillating steadily ( recommended to use an analog pointer instrument, which can be observed very clearly ) . If oscillation occurs, it indicates that there is an unstable vibration signal, acceleration It is also large, especially when the speed increases at the same time, it is very likely that there will be a bearing "sleeve" failure.

For the new equipment, although the vibration is very small and meets the national standards during the inspection and acceptance, there is a small amplitude of vibration and vibration at the bearing part. After excluding the bearing fit problem ( sleeve ) , it is most likely that there is a problem with the bearing geometry, such as The bearing steel ring is elliptical. When the rolling element passes the position of the long axis of the ellipse, the rolling element may be instantly stuck due to the reduction of the gap. The subsequent rolling element continues to squeeze, causing the sliding friction of the rolling element. Each rolling element will have sliding friction here. , Causing unstable signals to appear.