The function of the wheel is essential for the car to run. Whether the bearing in the wheel is good or not will directly affect the operation effect of the tire. Then how to judge whether the deep groove ball bearing is good or bad from the appearance? The following five aspects are compiled:
(1) All kinds of cracks, such as raw material cracks, forging cracks, heat treatment cracks and grinding cracks, will become the source of stress concentration and expand rapidly in the later operation of the bearing, resulting in bearing fracture, which has a great impact on the service life and work safety of the bearing.
(2) Various mechanical scars, such as abrasion, scratch, crush and collision, will cause poor bearing installation, eccentric load and stress concentration, and reduce the rotation accuracy and service life.
(3) Rust, black skin and pitting. The latter two are defects that are easy to store moisture and dirt, which are most likely to develop into rust. Corrosion is the pollution source leading to poor installation, early wear and fatigue. Serious corrosion will scrap the bearing.
(4) Peeling and folding, the local combination of these two defects with the base metal is not strong, and decarburization or carbon deficiency often exist around them in varying degrees. The material is easy to collapse, dent or wear, which is very unfavorable to the service life and accuracy of the bearing.
(5) For the riveting or welding quality of the cage, mainly observe whether the rivet head is offset, skewed, loose, lack of meat or "double eyelid", whether the welding position is correct, whether the welding spot is too large or too small, and whether the welding is not firm or welded.
