The main shaft system of the double spherical roller bearing arrangement is often hoisted down the tower because of the spalling of the inner ring raceway of the fixed end bearing, so we dismantle the main shaft system of the two fans that are hoisted down the tower, and completely summarize the root cause of the failure of the raceway of the inner ring of a fixed end bearing.
The failure of the raceway of the inner ring of the bearing mainly includes the fatigue peeling of the raceway and the cycloidal scratches of the inner ring flange and the rolling element, as shown in Figure 1-1 and Figure 1-2 respectively. The cycloidal scratch between the inner ring flange and the rolling element is due to the three-body scratch caused by the peeling cemented carbide fragments entering the angular gap between the inner ring flange and the rolling element.
As shown in Figure 1-1, the fatigue spalling of the raceway of the inner ring of the bearing is mainly concentrated on both sides of the rear raceway, which is contrary to the design concept of the center of the contact element line of the rolling element as the main bearing area at the beginning of the bearing design. This is due to the uneven wear and tear of the wall surface of the cage pocket hole or even fracture, causing the cage to lose the ability to maintain the attitude of the rolling element, in the semi-enclosed cage when acting with the rolling element, will produce an unbalanced torsional moment, so that the rolling element twists, which leads to a significant decrease in the consistency of the contact line between the rolling element and the inner ring raceway, and the middle position of the rolling voxel line is suspended, and the bearing on both sides, as shown in Figure 1-3, this undoubtedly changes the bearing bearing state, so that the contact stress between the rolling element and the raceway increases, And the stress concentration effect of the rolling element edge is aggravated.
Figure 1-1 Fatigue peeling of the inner ring raceway
Figure 1-2 Cycloidal scratches between the inner ring flange and the rolling element
Figure 1-3 Contact consistency of inner ring raceway (light transmission in the middle, contact on both sides)
As shown in Figure 1-1, it is worth noting that the initial position of fatigue spalling of the inner ring raceway is highly overlapping with the pseudo-Boolean indentation, which the author believes is not a coincidence.
In addition, under the action of axial load, the backward shift of the centerline of the contact stress distribution of the rolling element is an important factor leading to the stress effect at the edge of the rolling element, which undoubtedly aggravates the equivalent shear stress at the edge of the rolling element, and under the action of the equivalent shear stress, a large area of fatigue spalling occurs on the rolling element, as shown in Figure 1-4.
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(a) 1# unit
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(b) Unit 2#
Figure 1-4: Large-scale fatigue spalling of the rolling element