Various types of bearings have different characteristics due to their different designs. Due to the variability and complexity of the specific installation location and application scenarios of bearings, there is no fixed pattern for selecting bearing types. When selecting bearing types to adapt to the specific installation location and application conditions of a certain host, it is recommended to consider the following main factors comprehensively
Allow space
In mechanical design, the size of the shaft is generally determined first, and then bearings are selected based on the size of the shaft. Usually, ball bearings are used for small shafts; The main shaft uses cylindrical roller bearings, self-aligning roller bearings, tapered roller bearings (sometimes ball bearings can also be used). If the radial space of the bearing installation site is limited, bearings with smaller radial cross-sectional heights should be used. Such as needle roller bearings, certain series of deep groove ball bearings, angular contact ball bearings, cylindrical roller or self-aligning roller bearings, and thin-walled bearings. If the axial space of the bearing installation site is limited, bearings with smaller width dimensions can be used.
load
The size of the load is usually the determining factor in choosing the size of the bearing. Roller bearings have a greater load-bearing capacity than ball bearings with the same external dimensions. Ball bearings are usually suitable for light or medium loads, while roller bearings are suitable for withstanding heavy loads.
In terms of load mode, deep groove ball bearings and cylindrical roller bearings can be used for pure radial loads; For pure axial loads, thrust ball bearings and thrust cylindrical roller bearings can be selected; When there is both radial and axial load (combined load), angular contact ball bearings or tapered roller bearings are generally selected. If the radial load is large and the axial load is small, deep groove ball bearings and cylindrical roller bearings with both inner and outer rings having ribs can be used. If there is still significant deformation of the shaft or housing and installation misalignment, self-aligning ball bearings or self-aligning roller bearings can be selected. If the axial load is large and the radial load is small, thrust angular contact ball bearings and four point contact ball bearings can be selected; If self-aligning performance is also required, thrust self-aligning roller bearings can be selected.
speed
The working speed of rolling bearings mainly depends on their allowable operating temperature. Bearings with low frictional resistance and less internal heat generation are suitable for high-speed operation. When only subjected to radial loads, using deep groove ball bearings and cylindrical roller bearings can achieve higher speeds. If subjected to combined loads, angular contact ball bearings are recommended. By using specially designed high-precision angular contact ball bearings, extremely high rotational speeds can be achieved. The rotational speed of various thrust bearings is lower than that of radial bearings.
Rotation accuracy
For most machines, using bearings with zero tolerance is sufficient to meet the requirements of the host, but when there are strict requirements for the rotational accuracy of the shaft, such as machine tool spindles, precision machinery, and instruments, higher tolerance grade deep groove ball bearings, angular contact ball bearings, tapered roller bearings, cylindrical roller bearings, and thrust angular contact ball bearings should be selected.
rigidity
The rigidity of rolling bearings is determined by the elastic deformation that occurs when they bear loads. In general, this deformation is very small and can be ignored. However, in some machines, such as machine tool spindle systems, the static and dynamic stiffness of bearings have a significant impact on the characteristics of the system. Generally speaking, roller bearings have higher stiffness than ball bearings. Various types of bearings can also improve their rigidity to varying degrees by appropriately pre tightening.
Vibration and noise
The noise and vibration of bearings themselves are generally low. But for small and medium-sized motors, office machinery, household appliances, and instruments that have special requirements for noise and smooth operation, low-noise bearings are usually used.
Axial displacement
The most common configuration of bearings is to install a set of axially positioned "fixed bearings" at one end of the shaft and a set of axially movable "floating bearings" at the other end to prevent jamming caused by thermal expansion and contraction of the shaft. The commonly used "floating bearings" are cylindrical roller bearings with inner or outer rings without ribs. In this case, the fit between the inner ring and the shaft or the fit between the outer ring and the housing hole can be achieved through interference fit. Sometimes non separable deep groove ball bearings or self-aligning roller bearings can also be used as floating bearings, but during installation, clearance fit should be selected between the inner ring and shaft or the outer ring and the housing hole to ensure sufficient axial movement freedom for the inner or outer ring.
friction torque
The friction resistance of ball bearings is smaller than that of roller bearings, and the friction resistance of radial contact bearings is smaller when subjected to pure radial loads; When subjected to pure axial load, the frictional resistance of the axial contact bearing is small; When subjected to joint load, the angular contact bearing with a contact angle close to the load angle has the smallest frictional resistance. Ball bearings or cylindrical roller bearings are more suitable for instruments and machinery that require low friction torque. In addition, low friction torque bearings should avoid using contact seals, and it is recommended to use drip lubrication, oil air lubrication, or other lubrication methods that are beneficial for reducing wear.
Installation and disassembly
Bearings with cylindrical inner holes are used in machinery that requires frequent installation and disassembly. Separable angular contact ball bearings, tapered roller bearings, separable cylindrical roller bearings, needle roller bearings, and thrust bearings should be preferred. Bearings with conical inner holes can be installed on the shaft neck, or on the cylindrical shaft neck with the help of a tightening sleeve or a retraction sleeve, making installation and disassembly more convenient.

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