When choosing bearing types, it is very important to fully grasp the use conditions of bearings. The main analysis items are listed in the following table:

1) Installation space of bearings

The bearing type that can be accommodated in the bearing installation space pays attention to the rigidity and strength of the shaft when designing the shafting, so the shaft diameter, namely the bearing inner diameter, is generally determined first. However, rolling bearings have a variety of size series and types, from which the most appropriate bearing type should be selected.

2) load

Bearing load size, direction and nature [bearing load capacity is expressed by the basic rated load, its value is contained in the bearing size table] Bearing load is varied, such as the size of the load, whether only radial load, axial load is one-way or two-way, vibration or impact degree and so on. After considering these factors, the most appropriate bearing type is selected.

In general, the radial load capacity of bearings with the same inner diameter increases in the following order: deep groove ball bearings < angular contact ball bearings < cylindrical roller bearings < tapered roller bearings < self-altting roller bearings

3) speed

Can adapt to mechanical speed bearing type [to benchmark the threshold of the bearing rotating speed in limiting speed, its value is shown in table bearing size] bearing limit rotational speed is not only to take on bearing type is limited to the bearing size, cage type, precision grade, load condition and lubrication method, etc., therefore, when the choice must consider these factors. Most of the following bearings are used for high-speed rotation: deep groove ball bearings, angular contact ball bearings, cylindrical roller bearings.

4) Rotation accuracy

Bearing types with required rotation accuracy [Bearing dimensional accuracy and rotation accuracy have been standardized by GB according to bearing type] Machine tool spines, gas turbines and control machines require high rotation accuracy, high speed and low friction respectively, so bearings with grade 5 accuracy or above should be used. Generally, the following bearings are used: deep groove ball bearings, contact ball bearings, cylindrical roller bearings.

5) rigid

Type of bearing capable of meeting the rigidity required by mechanical shafting [When the bearing is loaded, the contact part of the rolling body and the raceway will produce elastic deformation.

“High rigidity” refers to the elastic deformation of the small amount of deformation] in the machine tool spindle and the car at the end of the reducer and other parts, while improving the rigidity of the shaft, but also must improve the rigidity of the bearing. The deformation of roller bearing under load is smaller than that of ball bearing. Applying pretightening (negative clearance) to bearings improves rigidity. This method is suitable for angular contact ball bearings and tapered roller bearings.

6) The relative tilt of the inner ring and the outer ring

Analyze the factors that cause the relative tilt between the inner ring and the outer ring of the bearing (such as the deflection of the shaft caused by load, the poor accuracy of the shaft and the shell or the installation error), and select the bearing type that can adapt to such conditions. If the relative tilt of the inner ring and the outer ring is too large, the bearing will be damaged by the internal load. Therefore, bearing types that can withstand this inclination should be selected. Generally speaking, the allowable inclination Angle (or aligning Angle) increases in the following order: cylindrical roller bearings, tapered roller bearings, deep groove ball bearings (angular contact ball bearings), aligning roller bearings (ball).

7) Installation and disassembly

When assembling and disassembling frequently, it is more convenient to use cylindrical roller bearings, needle roller bearings and tapered roller bearings whose inner and outer rings can be separated.Tapered hole self-aligning ball bearings and tapered hole self-aligning roller bearings can be easily assembled and disassembled by using fasteners or unloading sleeves.

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