What causes the difference in the quality of the finished bearing?

Bearings are almost everywhere in our life, from small shared bikes on the side of the road and household appliances at home to big spaceships in the sky and aircraft carriers in the water. Without bearings, none of these could exist.

The precision of rolling bearings is generally divided into five grades: P0, P6, P5, P4 and P2. The precision of bearings used on the spindle of precision machine tools should be P5 and above. And for CNC machine tools, machining centers and other high-speed, railway, aviation and other high-tech fields, need to choose P4 and superior ultra-precision bearings, P4 and superior ultra-precision bearings to the technical performance and reliability requirements are very high, more than half of the domestic demand are dependent on imports. So what causes the difference in the quality of the finished bearing?

At home and abroad a large number of experiments show that the ring, ball cage processing quality of bearing vibration with different degree of influence, one of the steel ball processing quality had evident effects on bearing vibration, the second is the ring of the processing quality, is the most important factors affecting the steel ball and ring roundness, surface roughness and surface waviness and knocked wounded, etc.

Level is not high precision of bearing steel ball products used by general discrete vibration value is big, serious surface defect (single points, group, pits, etc.), although the surface roughness, size, shape, error is not lower than outside, but after close set of bearing vibration value is high, and even produce different sound, the main problem is a striation no control (top, without proper test and analysis instrument). At the same time, the vibration resistance of the machine tool is poor, and there are problems in the grinding wheel, grinding disc, coolant and process parameters. On the other hand, the management level should be improved to avoid random quality problems such as bumps, scratches and burns.

For the ring, the most serious impact on bearing vibration is also the channel corrugations and surface roughness. For example, when the roundness of the inner and outer channels of small and medium-sized deep groove ball bearings is greater than 2μm, it will have a significant impact on the bearing vibration. When the corrugations of the inner and outer channels are greater than 0.7μm, the bearing vibration value will increase with the increase of the corrugations.