Tapered roller bearings play a vital role in industrial applications, especially when subjected to combined radial and axial loads. However, during maintenance or replacement, an incorrect installation method can result in serious mechanical damage, such as a broken small guard edge. This article will explore in detail the causes of this particular failure and provide effective preventive measures.
Fault symptom description
In a tapered roller bearing installation operation, technicians found that the small end of the inner ring had a continuous and spaced fracture, and the fracture area occupied about 2/3 of the overall structure, and the topography showed an obvious "sawtooth". These fracture points extend from the oil groove side of the raceway to the small end face, and some of the fracture shapes match the end of the conical roller, and the surface is gray and black, showing typical brittle fracture characteristics. In addition, the cage also showed signs of being knocked by external forces, deformed into a "droplet shape", and accompanied by a sag phenomenon (see Figure 1-4).
Cause analysis of fracture of small retaining edge
Through careful examination of the fault sample, it was determined that the problem was mainly caused by improper operations during the installation process. Specifically, the use of a hammer and copper rod to directly strike the cage or transfer the impact force through a steel rod during cold installation causes the cage to deform and indirectly causes the roller to exert excessive impact load on the small guard edge of the inner ring. When this force exceeds the bearing limit of the material, it causes a brittle fracture and ultimately makes the bearing fail.
Correct installation methods and suggestions
In order to avoid the above problems, the following are the recommended installation steps:
Choose the right installation method:
According to the bearing size and its working environment, reasonable choice of cold or hot loading method. Cold loading is suitable for most situations, while hot loading is more suitable for larger sizes or close-fitting occasions.
Ensure proper use of tools:
When cold loading, the installation sleeve should be preferred to prevent unnecessary external forces from acting on other parts of the bearing; If conditions do not allow, it is necessary to use a copper rod evenly against the inner ring, and symmetrical, circular tapping along the diameter direction to avoid excessive force.
Ensure installation accuracy:
During installation, it is important to ensure that the bearing end face is perpendicular to the journal, while taking care not to let the non-contact surface suffer any impact.
Upgrade personnel skill level:
Strengthen the professional training of installers to ensure that they are familiar with and follow the correct assembly process to eliminate the possibility of violent operation.
