Bearing quality inspection

national standards
1. National standard for vibration acceleration (commonly known as Z-standard)
This standard was formulated relatively early to measure the vibration acceleration value of bearings during rotation to determine the quality level of bearings. It is divided into three quality levels: Z1, Z2, and Z3, from low to high. At present, domestic bearing manufacturers are still using vibration acceleration values to evaluate the quality of bearings, which only briefly reflects the fatigue life of bearings.
2. Vibration speed standard (commonly known as V-standard)
Due to the fact that the original vibration acceleration standard has not yet been abolished, this standard appeared as a standard issued by the Ministry of Machinery Industry, and was developed based on European standards combined with the actual situation and needs of China. The quality level of bearings is determined by detecting the vibration speed of bearings (equivalent to national standards). It is divided into five quality levels: V, V1, V2, V3, and V4. The quality levels of various ball bearings range from low to high, including V, V1, V2, V3, and V4; The quality level of roller bearings (cylindrical and conical) is divided into four quality levels from low to high: V, V1, V2, and V3.
It reflects the quality of bearings by detecting the vibration and velocity of bearings in different frequency bands (low frequency, medium frequency, high frequency). It is possible to roughly analyze whether there are geometric size issues (such as steel ring ellipses), quality issues with raceways/rolling elements, and quality issues with cages in bearings. This has made significant progress compared to using vibration acceleration to evaluate bearing quality. At present, bearings exported to Europe in China, as well as our military and aerospace industry, all undergo bearing quality testing according to this standard. At the same time, testing the quality of bearings imported from Europe and identifying counterfeit imported bearings provide feasible means.
There are two parallel standards for bearing quality inspection, and bearings with a high quality level of "Z standard" may not have good quality performance when tested with "V standard", and there is no corresponding relationship between the two. This is particularly important in the quality inspection of bearings.