At present, the internal structural parameters of deep groove ball bearing in China are almost the same as those of advanced companies in other countries. However, the vibration and noise levels of such products in China are far different from those of foreign products. The main reason is the influence of factors in manufacturing and working conditions. From the perspective of the bearing industry, working conditions factors can be solved by putting forward reasonable requirements on the host machine. However, the bearing industry must solve the problem regarding how to reduce the vibration and noise caused by manufacturing factors. A large number of tests at home and abroad show that the machining quality of cage, ferrule and steel ball has different degrees of influences on bearing vibration. The machining quality of the steel ball has the most obvious influence on the bearing vibration, followed by the machining quality of the ring. The main influencing factors are roundness, waviness, surface roughness, surface bump and so on of the steel ball and ferrule.
The most prominent problem of Chinese steel ball products is the large dispersion of vibration values and serious surface defects (single point, group point, pit, etc.), although the surface roughness, size, shape and error are not lower than the level outside the ferrule. However, the vibration value of the bearing after fitting is high and even abnormal sound is produced. The main problem is that the waviness is not controlled (there is no standard, no suitable test and analysis instrument). Meanwhile, it explains that the vibration resistance of the machine is poor and there are problems with the grinding wheel, grinding disc, coolant as well as process parameters. On the other hand, the management level should be improved to avoid bump, scratch, burn and other random quality problems.
As for the ferrule, the most serious impact on the bearing vibration is also the groove ripple and surface roughness. For example, the vibration will be significantly affected when the roundness of the inner and outer channel of medium and small deep groove ball bearings is greater than 2μm. When the inner and outer channel ripple is greater than 0.7μm, the vibration value of the bearing increases with the increase of ripple degree. A serious knock on the channel can increase the vibration by more than 4dB and even lead to abnormal sounds.
Whether it is steel ball or ferrule, the waviness is produced by grinding. Although superfinishing can improve the waviness and reduce the roughness, the most fundamental measure is to reduce the waviness in the process of superfinishing to avoid random knock.