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1, according to the bearing operating conditions (including loading and the type of load, speed, lubricated, coaxial degree requirements, or non-positioning, installation and maintenance of the environment, environmental temperature, and so on), select the basic types, tolerances and internal clearance of the bearing;
2, depending on bearing force and conditions of work and life, bearing type is determined by calculation, or in accordance with requirements, selected bearing types and calculation of life;
3, check the selected load rating of the bearing and the speed limit.
Selection of bearing the main considerations are the speed limit, request Dacron life and load carrying capacity, other factors will help to determine the bearing type, structure, dimensions, and tolerances of final grades and clearance work, please.
Type selection
1) various types of rolling bearings with different characteristics, suitable for all kinds of different usage of the machine. Selection of bearing type, usually the following factors should be considered. Under normal circumstances: on selection of withstand thrust load thrust bearing, angular contact ball bearings, ball bearings for high-speed applications typically used, when subjected to heavy radial loads, the selection of roller bearings.
2) in mechanical design, first determining the dimensions of the shaft, then, according to shaft size selection of rolling bearings. Selection is usually small shaft ball bearings, large selection of roller bearings.
3) size, direction and nature of the load bearing
A) load most significant factor is the choice of bearings. Roller bearings to accommodate heavy loads and ball bearings to accommodate lighter or medium load.
B) in the direction of loading, when the joint is subjected to a radial and axial load, usually angular contact ball bearings or tapered roller bearings. When stand heavy axial loads, use thrust roller bearings.
C) bearing rigidity refers to deformation of bearing units the size you want. Elastic deformation of rolling bearings is small in most machines can do not have to take into account, but in some machines, such as machine tool spindles, bearing stiffness is an important factor, generally should use a cylindrical and tapered roller bearings. Because these two types of bearings at the time of loading, its rolling elements and Raceway belongs to point contact, less rigid.
In addition, the various bearings can also preload, achieve the purpose of increasing bearing rigidity. Angular contact ball bearings and tapered roller bearings, to prevent the vibrations of the shaft, increasing bearing rigidity, tend to exert a certain amount of axial force in advance when it was installed, its pressure. Preload is not too large. Too large, increase the bearing friction, temperature rise, influencing bearing service life.
Speed selection
1) when selecting a bearing, using the average of the bearing bore and outside diameter, mm. by multiplying the pitch circle diameter d-axis rotation speed (r/min) speed limit reached (DN) and the DN in the choice of bearing type and size is very important. Work at less than the speed limit 90% is good.
2) grease-lubricated bearings the speed limit lower than oil lubricated bearings the speed limit, bearings and oil have an impact on up to the speed limit. Provides several form bearing lubrication the speed limit correction factor (k). Please note that grease-lubricated bearings, the speed limit is generally only the bearings using a high quality duplication when a circulating oil system of the speed limit by 80%, but for oil mist lubrication system, the speed limit is generally lower than the same basic lubrication system of high 50%.
| Product Model | Inside Diameter | Outside Diameter | Thickness |
| 7203BDB NSK | 17 | 40 | 12 |
| 7203ADB NSK | 17 | 40 | 12 |