Bearing type selection

When selecting the bearing type, it is important to fully understand the conditions of use of the bearing. The main analysis items are listed below.

1) Bearing installation space: bearing type that can be accommodated in the bearing installation space

Since the design of the shafting pays attention to the rigidity and strength of the shaft, it is generally first determined the shaft diameter, that is, the bearing.

the inside diameter of.

However, rolling bearings are available in a variety of sizes and types, and the most suitable bearing type should be selected.

2) Load: the size, direction and nature of the bearing load [bearing capacity of the bearing

The basic load rating is shown in the bearing size table]

Bearing load is subject to change, such as the size of the load, whether there is only radial load, axial load is

One-way or two-way, the degree of vibration or shock, and so on. After considering these factors, choose the most suitable bearing type.

In general, the radial load capacity of bearings of the same inner diameter is increased in the following order: deep groove ball bearings < angular contact ball bearings < cylindrical roller bearings < tapered roller bearings < spherical roller bearings

3) Rotating speed: bearing type that can adapt to mechanical speed [limit of bearing speed)

The reference is expressed in terms of the limit speed and its value is shown in the bearing size table]

The limit speed of the bearing is not only determined by the bearing type but also the bearing size, cage type, fine

Degrees, load conditions, lubrication methods, etc. Therefore, these factors must be considered when selecting.

Most of the following bearings are used for high speed rotation:

Deep groove ball bearings, angular contact ball bearings, cylindrical roller bearings

4) Rotational accuracy: bearing type with the required rotation accuracy [The dimensional accuracy and rotation accuracy of the bearing have been standardized by GB according to the bearing type]

Machine tool spindles, gas turbines and control machines require high rotational accuracy, high speed and low friction, respectively. In this case, bearings with a precision of 5 or more should be used.

The following bearings are generally used: deep groove ball bearings, contact ball bearings, cylindrical roller bearings

5) Rigidity: A bearing type that satisfies the required rigidity of the mechanical shafting [When the bearing is subjected to load, the contact portion between the rolling element and the raceway is elastically deformed. “High rigidity” means that the amount of deformation of this elastic deformation is small]

In the machine tool spindle and the final stage of the vehicle, the rigidity of the shaft must be increased and the rigidity of the bearing must be increased.

Roller bearings are subjected to load deformation and are smaller than ball bearings

Applying a preload (negative clearance) to the bearing increases rigidity. This method is suitable for angular contact ball bearings and tapered roller bearings

6) Relative tilt of the inner ring and the outer ring: analyze the factors that cause the inner ring and the outer ring of the bearing to be relatively inclined (such as the deflection of the shaft caused by the load, the accuracy of the shaft and the outer casing or the installation error), and choose to adapt to this. Bearing type

If the relative inclination of the inner ring and the outer ring is too large, the bearing may be damaged by internal load. Therefore, you should choose the type of bearing that can withstand this tilt.

In general, the allowable tilt angle (or centering angle) is increased in the following order: cylindrical roller bearing, tapered roller bearing, deep groove ball bearing (angular contact ball bearing) spherical roller (ball) bearing

7) Installation and disassembly: frequency of assembly and disassembly, periodic inspection, etc.

When assembling and disassembling frequently, it is convenient to use cylindrical roller bearings with separate inner and outer rings, needle roller bearings and tapered roller bearings.

Tapered bore self-aligning ball bearings and tapered bore spherical roller bearings are easy to assemble and disassemble by using fasteners or withdrawal sleeves.