Damage of bearings - the channel peels off symmetrically in the circumferential direction
The symmetrical position spalling is manifested in the circumferential symmetrical position of the inner ring and the circumferential symmetrical position (that is, the short axis direction of the ellipse). The main reason is that the shell hole is too large or two semi-separated shell hole structure, which is especially obvious in the camshaft bearings for motorcycles.
When the bearing is pressed into the shell hole with large ellipse or when the two semi-separated shells are fastened, the outer ring of the bearing produces an ellipse, and the clearance in the direction of the short axis is obviously reduced or even negative.
Under the action of load, the inner ring rotates to produce circumferential peeling marks, and the outer ring only produces spalling marks in the symmetrical position of the short axis direction. This is the main reason for the early failure of the bearing. The test of the bearing failure parts shows that the outer diameter roundness of the bearing has changed from 0.8um controlled by the original process to 27um. This value is much greater than the radial clearance value.
Therefore, it can be confirmed that the bearing works under serious deformation and negative clearance, and it is easy to form abnormal sharp wear and spalling in the early stage on the working face.
The countermeasures are to improve the machining accuracy of shell hole or not to adopt the split structure of shell hole as much as possible.