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Shanghai Shang Shaft Bearing Quality Inspection Institute Co., Ltd.

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Bearing assembly and inner and outer ring fixing method

2020-07-29 10:24

The main function of the bearing is to support the mechanical rotating body, ensure the working position and accuracy of the shaft and the transmission parts on the shaft, reduce friction and wear, and bear the load. In daily applications, the assembly of bearings generally requires professional operation guidelines or experienced bearing engineers. Here are some common bearing assembly methods and techniques.

Common assembly methods for bearings

1. Knocking methodWhen the matching interference is small, the bearing can be loaded with a hand hammer. The method is to put copper rod or soft iron and sleeve on the inner ring or outer ring of the bearing, and use a hand hammer to knock the copper rod symmetrically to load the bearing evenly.

2. Top pressure methodWhen the matching interference is large, a press can be used to press into the bearing, and the sleeve must be placed when pressing.

3. Temperature difference methodWhen the matching interference is very large, the temperature difference method can be used for assembly, the temperature difference method for bearing assembly, and the hot assembly method is often used for maintenance.

The heating method is electric heater and oil bath heating, of which electric heater is widely used in the field.

1. Preparation before hot assembly
The matching size, diameter, boss, round root and chamfer of the parts shall be rechecked and the matching surface shall be cleaned. The flat key of the key part should be repaired and fixed to the shaft according to the keyway of the shaft and hole in advance. For diagonal keys or tangential keys, guide keys are used to ensure the mutual position of the keyways. Before hot installation, the retaining ring, gasket and other components shall be repaired and trial assembled without error, and assembled after verification.

The alignment shall be made before hot installation, and the engraved line mark and direction indication mark shall be made at the same time. The assembly surface is coated with lubricating oil to reduce the frictional resistance during installation. Before hot assembly, make a measuring ruler to measure and confirm whether the heated workpiece has been heated to the assembly condition. The ruler should meet the conditions of light use and not easy to deform, and can accurately measure the thermal expansion of the measured part at a long distance from the heat source.The ruler can be made of metal rod or metal plate, and the actual size should be equal to the nominal size of the diameter of the measured part plus the maximum interference at the fit plus the minimum clearance necessary for assembly (its structure is shown in the figure).After the heating part is heated through, measure the ruler.Only when it can pass freely and the measured results are confirmed to be accurate through reinspection can heating be terminated and hot assembly operation can be carried out.

2. The method of eliminating axial clearance in hot equipment

 

After hot installation, due to the result of cooling shrinkage, there is often an axial gap at the axial positioning shoulder between the wheel and the shaft, which is essentially the phenomenon that the assembly is not in place and the positioning is unreliable. Therefore, the gap should be eliminated in the hot pack.The general use of impact method, bolt tension method, weight method.

 Positioning and fixing method of bearing inner and outer rings

a) The shaft retaining ring is embedded in the groove of the shaft, which is mainly used when the axial force is not large and the rotation speed is not high;

B) Fasten the shaft end retaining ring fixed with screws, which can bear large axial force at high speed, and the screws shall be provided with anti-loosening measures;
c) Fasten with round nuts and stop washers, mainly for high speed and large axial force;

d) Position with tapered sleeve, tighten with stop washer and round nut, and apply to the bearing whose inner ring is a tapered hole on the optical axis.

e) Fasten the hole embedded in the groove of the housing with a circlip, mainly used when the axial force is not large and the size of the bearing device needs to be reduced;
f) Fasten with bearing end cover for all kinds of centripetal, thrust and centripetal thrust bearings with high rotating speed and large axial force;
g) Insert the shaft circlip into the stop groove of the bearing outer ring for tightening, when the shell is inconvenient to set the shoulder;

 

h) Fasten with threaded ring, which is used for high bearing speed and large axial force, but is not suitable for fastening with bearing end cover.

Axial fixation of inner and outer rings of rolling bearings

 

In order to prevent the bearing from axial movement relative to the shaft or seat hole when bearing axial load, the bearing inner ring and shaft, outer ring and seat hole must be axially fixed. The common axial fixing methods of inner and outer rings of rolling bearings are as follows:

Axial fixation of inner and outer rings of rolling bearings

In order to prevent the bearing from axial movement relative to the shaft or seat hole when bearing axial load, the bearing inner ring and shaft, outer ring and seat hole must be axially fixed. The common axial fixing methods of inner and outer rings of rolling bearings are as follows:

Axial fixation of inner and outer rings of rolling bearings

In order to prevent the bearing from axial movement relative to the shaft or seat hole when bearing axial load, the bearing inner ring and shaft, outer ring and seat hole must be axially fixed. The common axial fixing methods of inner and outer rings of rolling bearings are as follows:

Axial fixation of inner and outer rings of rolling bearings

In order to prevent the bearing from axial movement relative to the shaft or seat hole when bearing axial load, the bearing inner ring and shaft, outer ring and seat hole must be axially fixed. The common axial fixing methods of inner and outer rings of rolling bearings are as follows: