When selecting a bearing type, it is very important to fully understand the service conditions of the bearing. The following table lists the main analysis items:
Analyzing Items Selection Method
When selecting a bearing type, it is very important to fully understand the service conditions of the bearing. The following table lists the main analysis items:
Analyzing Items Selection Method
1) The bearing installation space can be accommodated in the bearing installation space. Since the rigidity and strength of the shaft are emphasized when designing the shaft system, the shaft diameter, that is, the inner diameter of the bearing, is generally determined first.
However, there are many size series and types of rolling bearings, and the most suitable bearing type should be selected from them.
2) The size, direction and nature of the load bearing load [the load capacity of the bearing is expressed by the basic rated load, and its value is shown in the bearing size table] the bearing load is full of changes, such as the size of the load, whether there is only radial load, axial load Is it one-way or two-way, the degree of vibration or shock, and so on. After considering these factors, choose the most suitable bearing type.
Generally speaking, the radial load capacity of bearings with the same inner diameter increases in the following order: deep groove ball bearing < angular contact ball bearing < cylindrical roller bearing < tapered roller bearing < spherical roller bearing
3) The type of bearing whose speed can adapt to the mechanical speed [the limit value of the bearing speed is represented by the limit speed, and its value is shown in the bearing size table] The limit speed of the bearing is not only taken from the bearing type but also limited to the bearing size, cage type, and accuracy level , load conditions and lubrication methods, etc., therefore, these factors must be considered when selecting.
The following bearings are mostly used for high speed rotation:
Deep groove ball bearings, angular contact ball bearings, cylindrical roller bearings
4) Rotation accuracy Bearing type with the required rotation accuracy [The dimensional accuracy and rotation accuracy of bearings have been standardized by GB according to the bearing type] Machine tool spindles, gas turbines and control machines require high rotation accuracy, high speed and low friction respectively, At this time, bearings with grade 5 or higher precision should be used.
Generally the following bearings are used:
Deep groove ball bearings, contact ball bearings, cylindrical roller bearings
5) The type of bearing whose rigidity can meet the rigidity required by the mechanical shaft system [When the bearing is under load, the contact part between the rolling body and the raceway will produce elastic deformation. "High rigidity" means that the amount of deformation of this elastic deformation is small] In the machine tool spindle and the final reduction gear of the automobile, while improving the rigidity of the shaft, the rigidity of the bearing must also be improved.
The deformation of roller bearings under load is smaller than that of ball bearings.
Applying preload (negative clearance) to the bearing can increase rigidity. This method is applicable to angular contact ball bearings and tapered roller bearings.
6) The relative inclination of the inner ring and the outer ring analyzes the factors that cause the relative inclination of the inner ring and the outer ring of the bearing (such as the deflection of the shaft caused by the load, the poor accuracy of the shaft and the outer shell, or the installation error), and select the one that can adapt to this Bearing type of service conditions. If the relative inclination between the inner ring and the outer ring is too large, the bearing will be damaged due to internal load. Therefore, a bearing type that can withstand this inclination should be selected.
In general, the allowable inclination angle (or self-aligning angle) increases in the following order:
Cylindrical roller bearings, tapered roller bearings, deep groove ball bearings (angular contact ball bearings), spherical roller (ball) bearings
7) The frequency and method of assembly and disassembly of installation and disassembly, regular inspection, etc. When assembly and disassembly are frequent, it is more convenient to use cylindrical roller bearings with separable inner ring and outer ring, needle roller bearings and tapered roller bearings.
Tapered hole self-aligning ball bearings and tapered hole self-aligning roller bearings can be easily assembled and disassembled by using fasteners or withdrawal sleeves.
