Reasonable selection of high-precision imported bearing application methods

It must be recognized that clearance is an important factor in the normal operation of imported bearings. Choosing the appropriate bearing clearance has many benefits for the bearing: it can distribute the load reasonably between the rolling elements; Can limit the axial and radial displacement of the shaft (or housing) to ensure the rotational accuracy of the shaft; Ensure that imported bearings can operate normally at the required temperature; It can reduce the vibration and noise of bearings during operation, indicating that bearing clearance has a significant impact on bearing life, temperature rise, vibration, and noise. When selecting bearing clearance, in addition to considering the working conditions of the bearing (such as load, speed, temperature, etc.) and the requirements for the performance of the bearing (such as friction torque, vibration and noise, rotation accuracy, etc.), the following should also be considered:

1. The interference fit between the bearing, shaft, and housing reduces the clearance;

When the bearing is working, the temperature difference between the inner and outer rings causes a decrease in clearance;

3. The manufacturing materials of the shaft and housing may reduce or increase the clearance due to different coefficients of expansion.

Experience has shown that the suitable working clearance for ball bearings is approximately zero; For the suitable working conditions of roller bearings, a small amount of working clearance should be maintained. In components that require good support rigidity, such as machine tool spindles, there may also be a certain amount of pre tightening.

High precision bearings refer to imported bearings with high rotational accuracy, dimensional accuracy, and low surface roughness. In China's standards, P4 grade and higher than P4 grade bearings are used. For example, P2 grade bearings are high-precision bearings, which are roughly equivalent to American standards ABEC7 and ABEC9, and international standards ISOP4 and P2. International standards are recognized and adopted by many countries, such as Japan, Germany, and France.

Through precision machining, various types of rolling bearings can meet high-precision requirements, but in the application of high-precision imported bearings, angular contact ball bearings are more commonly used. In metal cutting machine tools with high precision and high stiffness requirements, double row short cylindrical roller bearings are also used in the spindle, followed by tapered roller bearings.

Currently, due to the development of bearing processing technology, the international level of actual finished product error of precision bearings at all levels is mostly below half of the standard value. For example, the roundness of imported bearings for machine tools is 0.3 μ m, while that used in computers is 0.25 μ m.

Overall, when selecting precision bearings, users should first choose from the three types mentioned above. Moreover, even among these three types, not every specification is produced with precision products, and it is necessary to search for samples from various bearing companies or manufacturers, or inquire with their bearing sales departments.