When the outer spherical bearing rotates, the raceway surfaces of the inner and outer rings are in rolling contact with the rolling elements, so the running track is the dark surface. It is not abnormal for the running track to be attached to the raceway surface. From this, the load conditions can be known. Therefore, when disassembling the TIMKEN bearing, please pay close attention and observe the running track of the raceway surface.
If you carefully observe the running track, you will find that it only bears radial loads, bears large axial loads, bears moment loads, or has extreme rigidity unevenness on the bearing box. You can check whether the bearing has been subjected to unexpected loads and whether the installation error is too large, etc., which can become a clue to investigate the cause of the outer spherical bearing damage.
Lubrication is very important, not only for TIMKEN bearings, but also for all bearings. But please note that it is not advisable to add too much grease to the bearings. Then it is time to replace the lubricant of the bearings. After draining the old oil from the bearings lubricated with engine oil, if possible, fresh oil should be added and the machine should be rotated at a low speed for a few minutes. The engine oil should collect the remaining contaminants as much as possible, and then drain the oil. When replacing the grease of the bearings lubricated with grease, the cleaner used should avoid contacting any part of the outer spherical bearing with cotton. Because these residual fibers may wedge between the rolling parts and cause damage, especially for the application of small bearings, this problem needs more attention.
When checking the bearings, never expose them to pollutants or moisture. If work is interrupted, cover the machine with oil paper, plastic sheet or similar material. If cleaning an uncovered bearing without disassembly and inspection is possible, clean it with a coating brush dipped in petroleum solvent, then wipe it dry with a lint-free cloth or blow it dry with compressed air (be careful not to start the bearing assembly to rotate). Use a small mirror and a probe similar to that used by dentists to check the bearing's track surface, retainer and beads. Do not clean TIMKEN bearings with sealing covers or dustproofs; just wipe their outer surfaces. If the bearing is damaged, it needs to be replaced. Replacing the bearing during the regular downtime maintenance period is much more economical than the loss of sudden downtime caused by bearing damage.
Contact fatigue failure refers to the failure of the bearing working surface under the action of alternating stress. Contact fatigue spalling occurs on the bearing working surface and is often accompanied by fatigue cracks. It first occurs at the maximum alternating shear stress below the contact surface, and then expands to the surface to form different spalling shapes, such as pitting or pitting spalling, and spalling into small pieces is called shallow spalling.
Wear failure refers to the failure caused by the continuous wear of the working surface metal due to the relative sliding friction between the surfaces. Continuous wear will cause the bearing parts to gradually damage, and eventually lead to the loss of bearing dimensional accuracy and other related problems. Wear may affect the shape change, increase the fit clearance and change the working surface morphology, which may affect the lubricant or cause it to be contaminated to a certain extent, resulting in the complete loss of lubrication function, thus causing the outer spherical bearing to lose its rotation accuracy and even fail to operate normally. Wear failure is one of the common failure modes of various TIMKEN bearings, and can usually be divided into the most common abrasive wear and adhesive wear according to the wear form.
1. The outer ring running track of a cylindrical roller bearing used when the inner ring is rotated with load when a radial load is correctly applied.
2. The inner ring and the outer ring are relatively inclined, the shaft has a larger deflection, and the running track of the raceway surface produces light and dark in the longitudinal direction. At the exit of the load circle, the running track is inclined, and the double-row tapered roller bearing makes the inner ring rotate.
3. It indicates the running track of the outer ring when only radial load is borne. L indicates the running track when only axial load is borne. When the inner ring and outer ring are relatively tilted and only radial load is borne, the running track deviates from the position of 180° between the two row track surfaces .
