The main function of a bearing is to support the mechanical rotating body, ensure the working position and precision of the shaft and the transmission components on the shaft, reduce friction and wear, and bear loads. In daily applications, the assembly of bearings generally requires professional operation guidance or experienced bearing engineers. Here are several common bearing assembly methods and techniques introduced for you.

Common Assembly Methods of Bearings

1. Tapping Method: When the interference fit amount is small, a hand hammer can be used to tap the bearing into place. The method is to place a copper rod, soft iron, or sleeve on the inner or outer ring of the bearing, and use a hand hammer to tap the copper rod symmetrically and evenly to install the bearing.

2. Pressing Method: When the interference fit amount is relatively large, a press can be used to press the bearing in. A sleeve must be placed when pressing the bearing in.

3. Temperature Difference Method: When the interference fit amount is very large, the temperature difference method can be used for assembly. In maintenance, the thermal assembly method is often adopted. Heating methods include electric heaters and oil bath heating, and electric heating is widely used on-site.

Common Problems and Key Links in Bearing Assembly

1. Preparation before Thermal Assembly

The mating dimensions, diameters, bosses, fillets, and chamfers of the parts should be rechecked for correctness, and the mating surfaces should be cleaned. The flat key of the keyed part should be repaired and fitted in advance according to the keyways of the shaft and the hole and fixed to the shaft. For inclined keys or tangential keys, a guide key should be used to ensure the relative positions of the keyways. Before thermal assembly, parts such as retaining rings and gaskets should be repaired, fitted, and trial-assembled without errors, and assembled after passing the inspection.

Before thermal assembly, align the parts, and make scribed marks and direction indication marks. The assembly surface should be coated with lubricating oil to reduce the frictional resistance during the loading process. Before thermal assembly, make a measuring ruler to measure and confirm whether the heated workpiece has been heated to the assembly conditions. The measuring ruler should meet the conditions of being easy to use and not easy to deform, and be able to accurately measure the thermal expansion of the measured part away from the heat source.

The ruler can be made of a metal rod or a metal plate. The actual size should be equal to the nominal size of the diameter of the measured part plus the maximum interference at the mating part and the minimum clearance required for assembly.

After the heated part is thoroughly heated and the measuring ruler can pass through freely, and after rechecking and confirming that the measurement result is accurate, the heating can be stopped, and the thermal assembly operation can be carried out.

2. Methods to Eliminate Axial Clearance during Thermal Assembly

After thermal assembly, due to cooling and shrinkage, axial clearance often appears at the axial positioning shoulders of the wheel and the shaft. The essence of this is that the assembly is not in place and the positioning is unreliable. Therefore, the clearance should be eliminated during thermal assembly. Generally, there are the impact method, the bolt tightening method, and the method of pressing heavy objects.