1、 Bearing structure and performance

At present, double row tapered roller bearings are used as a typical TDO structure, which is composed of two inner ring components, one intermediate ring, and one outer ring. The bearings can withstand axial loads in two directions, and the rolling element has linear contact with the inner and outer ring channels, which has a certain radial and axial load capacity, but does not have centering performance. Any misalignment problem can cause uneven bearing force and performance degradation of the shaft.

2、 Bearing damage characteristics

The main reason is the wear of the cage, which ultimately leads to lockup. The characteristics are as follows:

1. The positioning bearing is damaged in a single row, mostly concentrated in the outer row.

2.In addition to the damaged cage, the large end face of the rolling element and the inner ring edge of the outer row are severely worn, with rolling, sinking steps, and high temperatures.

3. The inner row of rolling elements is normally worn, with a bright surface and no problems with high temperatures or rolling steps.

4. The corresponding cage pocket hole of the rolling element is worn, deformed during rolling, and cracked at high temperatures

3、 Cause analysis

From the analysis of the above damage characteristics, it can be concluded that when the rolling mill runs at high speed, there is a large abnormal axial load. The axial load acts on the outer row of rollers, causing serious sliding friction between the end face of the roller and the rib, causing high temperature oil shortage. At the same time, the ball base surface of the end face of the roller and the end face is worn and damaged, and the rotation track of the roller is deflected, which leads to unstable operation of the cage and periodic shear force, The above three phenomena were triggered, leading to the damage of the cage, which directly led to the final locking and burning of the bearing.

4、 Suggested adjustment measures

1. Ensure that the eccentricity of the line in the hole of the main bearing box and the hole of the positioning bearing box meets the requirements of the drawing, and avoid the deviation of the center line of the main bearing and the positioning bearing, which will cause the wear of the cage when rotating;

2. Increase the lubrication amount of the positioning bearing;

3. Adjust the tightness of the outer ring. Before installation, first measure the distance between the end face of the gland and the end face of the positioning bearing, determine the thickness of the gasket, and ensure that there is a clearance of 0.05-0.10mm between the gland and the end face of the positioning bearing when locking after installation;

4. Customized thickened cage to improve the strength and deformation resistance of the cage.