At present, China's deep groove sealed ball bearings are almost the same as the internal structural parameters of foreign advanced companies. However, the vibration and noise levels of such products in China are far from the foreign products, mainly due to the influence of manufacturing machine tools and working conditions. .
From the perspective of the bearing machine tool industry, the working conditions can be solved by reasonable requirements for the host, and how to reduce the vibration and noise caused by manufacturing factors is a problem that the bearing industry must solve.
A large number of tests at home and abroad have shown that the processing quality of cages, ferrules and steel balls has different degrees of influence on bearing vibration. The processing quality of steel balls has the most obvious influence on bearing vibration, followed by the processing quality of ferrules. The influencing factors are the roundness, waviness, surface roughness, surface flaws of the steel ball and the ferrule.
The most prominent problems of China's steel ball products are large dispersion of vibration values and serious surface defects (single points, group points, pits, etc.), although the surface roughness, size, shape, and error are not lower than the level of the circle, but the set The rear bearing has high vibration value and even produces abnormal sound. The main problem is that the waviness is not controlled (no standard, no suitable test and analysis instrument), and the machine tool has poor vibration resistance. There are problems with the grinding wheel, grinding disc, coolant and process parameters. On the other hand, it is necessary to improve the management level and avoid any occasional quality problems such as bruises, scratches and burns.
For the ferrule, the most serious vibration of the bearing is the channel waviness and surface roughness. For example, when the circularity of the inner and outer channels of small and medium-sized deep groove ball bearings is greater than 2μm, the bearing vibration will be significantly affected. When the internal and external channel waviness is greater than 0.7μm, the bearing vibration value increases with the increase of the waviness, and the channel is seriously injured. The vibration can be increased by more than 4db, and even abnormal sounds appear.
Whether it is a steel ball or a ferrule, the waviness is generated by grinding. Although ultra-finishing can improve the waviness and reduce the roughness, the most fundamental measure is to reduce the waviness during the grinding process and avoid randomness. There are two main measures for bump injury:
First, reduce the vibration of the rolling surface grinding superfine, obtain good surface processing shape accuracy and surface texture quality to reduce vibration, the grinding super machine tool must have good vibration resistance, and the important structural parts such as the bed have vibration absorption, super The oil stone oscillating system of the precision machine tool has good anti-vibration performance; the second is to improve the grinding speed. The foreign grinding 6202 outer raceway generally adopts 60,000 electric spindles, and the grinding speed is above 60m/s, which is generally much lower in China. Limitation of spindle and main bearing performance. In high-speed grinding, the grinding force is small, the grinding deterioration layer is thin, it is not easy to burn, and the machining accuracy and efficiency can be improved, which has great influence on low-noise ball bearings; the dynamic and static stiffness of the main shaft and its speed characteristics are low-noise ball bearings. Grinding vibration has a great influence. The higher the stiffness, the less sensitive the grinding speed is to the change of grinding force. The smaller the vibration of the grinding system is. The rigidity of the spindle bearing is increased. The random dynamic balance technology is used to improve the vibration resistance of the grinding spindle. Sex. The vibration speed of foreign grinding heads (such as gamfior) is about one-tenth of that of the domestic general spindle.