Various types of bearings have different characteristics due to different designs.There is no fixed mode for bearing type selection due to the specific mounting position of bearing and the variability and complexity of application occasions.In order to adapt to the specific installation position and application conditions of a certain host, the following factors should be considered comprehensively:
1. Dimension space
Mechanical design, generally determine the size of the shaft first, and then choose the bearing according to the size of the shaft.Generally, ball bearings are used for small shafts.Cylindrical roller bearings, spherical roller bearings, tapered roller bearings (ball bearings are sometimes used) are used for the big shaft.
If the radial space of bearing mounting position is restricted, bearings with smaller radial section height should be used.If the axial space of the bearing mounting position is restricted, the bearing with a smaller width can be used.
2. Bearing load
The load size is usually the determinant of the bearing size.The bearing capacity of roller bearing is larger than that of ball bearing with the same dimension.Ball bearings are generally used for light or medium loads and roller bearings for heavy loads.
If the axial load is large and the radial load is small, the thrust angle contact ball bearing and four point contact ball bearing can be selected.If you still want to adjust the performance, you can choose to adjust the thrust roller bearing.
3. Speed
The working speed of the rolling bearing mainly depends on the allowable operating temperature.Bearing with low friction resistance and less internal heat is suitable for high speed operation.When only bearing radial load, deep groove ball bearing and cylindrical roller bearing can reach high speed. If bearing combined load, angular contact ball bearing should be selected.Special designed high precision angular contact ball bearing can achieve high speed.The speed of all kinds of thrust bearings is lower than that of radial bearings.
4. Rotation speed
For the majority of machinery, choose a level 0 tolerance of bearing is enough to meet the requirements of the host, but on the axis of rotation accuracy have strict requirements, such as spindle, precision machinery and instrument etc., should choose high tolerance grade of deep groove ball bearings, angular contact ball bearings, tapered roller bearings, cylindrical roller bearings and thrust angular contact ball bearings.
5. Axial movement
The most common way to configure bearings is to install a set of shaft-oriented "identical bearings" at one end of the shaft, and a set of axially movable "movable bearings" at the other end to prevent sticking due to the expansion and contraction of the shaft.The commonly used "floating bearing" is the cylindrical roller bearing with inner ring or outer ring without baffle. At this time, the matching of inner ring and shaft or the matching of outer ring and outer ring can be adopted.
Sometimes, non-separable deep groove ball bearings or spherical roller bearings can be selected as floating bearings, but clearance fit should be selected for the inner ring and shaft or outer ring and outer hole during installation to ensure that the inner ring or outer ring has enough freedom of axial movement.
6. Friction torque
The friction resistance of ball bearing is smaller than that of roller bearing.When the axial load is applied, the friction resistance of the axial contact bearing is small.When combined load is applied, the friction resistance of bearing contact angle is the least.Ball bearings or cylindrical roller bearings are more suitable for equipment and machinery where low friction torque is required.In addition, the low friction torque bearing should avoid using contact seal, at the same time, it is recommended to use drip lubrication, oil and gas lubrication or other lubrication methods that are conducive to wear reduction.
7. Installation and disassembly
The bearings with cylindrical inner bore are used for mounting and disassembling the machines frequently, the separation angular contact ball bearings, taper roller bearings, detachable cylindrical roller bearings, needle roller bearings and thrust bearings should be preferred.Bearings with conical bore can be mounted on the journal, or on the cylindrical journal by means of a tightener or back-off sleeve.
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