INA rolling bearing selection and application principles
The INA bearing arrangement includes not only rolling bearings, but also bearing-related components, such as shafts and bearing seats. Lubricant is also a very important part of the bearing configuration, because the lubricant must prevent the wear and corrosion of the SF-1 oil-free bearing, so that the bearing can fully play its role. In addition, the seal is also a very important component, and the performance of the seal is very important for the cleaning of the lubricant and the cleaning of the SPB self-lubricating bearing. Keeping clean has a profound impact on the service life of bearings, which is why lubricants and seals have become part of SKF's bearing business WQZD self-lubricating bearings with ribs.
(1) The size, direction and nature of the load on the bearing
Load is the most important factor in selecting bearings. Roller bearings are used to bear heavier loads, and ball bearings are used to bear light or medium loads. Bearings made of carburized steel or bainite quenched can bear shock and vibration loads. In terms of the direction of the load, deep groove ball bearings, cylindrical roller bearings or needle bearings can be selected when bearing pure radial loads. When bearing small pure axial load, thrust ball bearing can be selected; when bearing larger pure axial load, thrust roller bearing can be selected. When INA bearings are subjected to combined radial and axial loads, angular contact ball bearings or tapered roller bearings are generally used. For cantilever support structures, tapered roller bearings or angular contact ball bearings are often used, and they are used in pairs.
(2) The space and location of the machinery occupied by the bearing
In mechanical design, the size of the shaft is generally determined first, and then the rolling bearing is selected according to the size of the shaft. Usually, ball bearings are used for small shafts, and roller bearings are used for large shafts. However, when the INA bearing is restricted in the diameter direction of the machine, needle roller bearings, extra-light and ultra-light series ball or roller bearings are selected; when the axial position of the bearing in the machine is restricted, narrow or Ball or roller bearings in the special narrow series.
(3) The rigidity of the bearing
The rigidity of a bearing refers to the amount of force required to produce a unit deformation of the bearing. The elastic deformation of rolling bearings is very small, and it is not necessary to consider in most machines, but in some machines, such as machine tool spindles, bearing rigidity is an important factor. Generally, cylindrical and tapered roller bearings should be used. Because these two types of bearings bear the load, their rolling elements and raceways are in point contact, and the rigidity is poor. In addition, various types of bearings can also be pre-tightened to achieve the purpose of increasing the supporting rigidity. For example, angular contact ball bearings and tapered roller bearings, in order to prevent shaft vibration and increase supporting rigidity, a certain axial force is often applied in advance during installation to make them compress each other. It is particularly pointed out here that the preload amount should not be too large. When it is too large, the friction of the INA bearing will increase, and the temperature rise will increase, which will affect the service life of the bearing.
(4) The self-aligning performance of the bearing
When the center line of the shaft is different from the center line of the bearing seat, there is an angular error, or the shaft has a large distance between the two supports and the rigidity of the shaft is small, and it is easy to bend or tilt. Center ball or spherical roller bearings, and outer ball bearings. This type of INA bearing can maintain normal operation when the shaft is slightly tilted or bent.