When inspecting the centripetal joint bearing removed during the regular maintenance and operation of fag bearing equipment and the replacement of peripheral parts, it is necessary to judge whether the secondary bearing parts can be reused and record the good or bad use.
Also carefully investigate and record the removed bearings and appearance. In order to find out and investigate the remaining amount of lubricant, the bearing should be well cleaned after sampling.Solution to Failure of Fag Radial joint Bearing Without Reason During Operation
Solution to Failure of Fag Radial joint Bearing Without Reason During Operation
1. Contact fatigue failure
Contact fatigue failure refers to the failure of fag bearing working surface caused by alternating stress. Contact fatigue spalling occurs on the working surface of radial joint bearing, which is often accompanied by fatigue cracks.
It first occurs from the large alternating shear stress below the contact surface, and then extends to the surface to form different spalling shapes, such as pitting or pitting spalling, which is called shallow spalling.
Due to the gradual expansion of the spalling surface, it often expands to the deep layer, forming deep spalling. Deep spalling is the fatigue source of contact fatigue failure.Solution to Failure of Fag Radial joint Bearing Without Reason During Operation
2. Wear failure
Wear failure refers to the failure caused by the continuous wear of the metal on the working surface caused by the relative sliding friction between the surfaces. Continuous wear will cause the parts of radial plain bearing to be damaged gradually, and eventually lead to the loss of bearing dimensional accuracy and other related problems.
Defects such as microcracks, shrinkage cavities, bubbles, large foreign objects, overheated tissue and local burns of bearing parts will also cause fracture at the defect during impact overload or violent vibration, which is called defect fracture.
It should be pointed out that the above defects can be correctly analyzed by instruments in the factory re inspection of raw materials, quality control of forging and heat treatment and processing process control of radial plain bearings in the manufacturing process, and the control must be strengthened in the future. But generally speaking, most of the bearing fracture failures are overload failures.Solution to Failure of Fag Radial joint Bearing Without Reason During Operation
4. Clearance change failure
In the work of radial joint bearing, due to the influence of external or internal factors, the original matching clearance is changed, the accuracy is reduced, and even “bite” is called clearance change failure. External factors such as excessive interference, improper installation, expansion caused by temperature rise, instantaneous overload, etc., and internal factors such as residual austenite and residual stress in an unstable state are the main reasons for the change and failure of clearance.Solution to Failure of Fag Radial joint Bearing Without Reason During Operation
Check the raceway surface, rolling surface and mating surface of fag bearing and the wear state of cage for damage and abnormalities, especially observe the running track of raceway surface. Judge whether the bearing can be used again after considering the degree of bearing damage, machine performance, importance, operating conditions, inspection cycle, etc.Solution to Failure of Fag Radial joint Bearing Without Reason During Operation
According to the inspection results, if the fag bearing is found to be damaged or abnormal, please find out the causes and formulate countermeasures according to the phenomenon of bearing damage. In addition, according to the inspection results, if there are the following defects, the radial joint bearing can no longer be used and needs to be replaced with a new bearing.
Wear may affect the change of shape, the increase of fit clearance and the change of working surface morphology, may affect the lubricant or make it polluted to a certain extent, resulting in the complete loss of lubrication function, so that the radial joint bearing loses the rotation accuracy and even can not operate normally.
Wear failure is one of the common failure modes of various fag bearings. According to the wear form, it can be divided into common abrasive wear and adhesive wear.Solution to Failure of Fag Radial joint Bearing Without Reason During Operation
Abrasion of the hard working surface of the bearing caused by the abrasion of foreign particles or the grinding groove caused by the relative movement of foreign particles on the working surface of the bearing. Hard particles or foreign matters may come from the inside of the main engine or from other adjacent parts of the main engine system, and are sent into the radial plain bearing by the lubricating medium.
Adhesive wear refers to the uneven stress on the friction surface due to the micro bulge or foreign matter on the friction surface. When the lubrication conditions are seriously deteriorated, the local deformation and friction micro welding of the friction surface are easy to be caused due to the heat generated by local friction.
In serious cases, the surface metal may be locally melted, and the force on the contact surface will tear the local friction welding point from the substrate and increase the plastic deformation. This cycle of adhesion tear adhesion constitutes adhesive wear. Generally speaking, slight adhesive wear is called scratch and severe adhesive wear is called bite.Solution to Failure of Fag Radial joint Bearing Without Reason During Operation
3. Fracture failure
The main causes of fag bearing fracture failure are defect and overload. When the external load exceeds the material strength limit and causes the part to break, it is called overload fracture. The main cause of overload is the sudden failure or improper installation of the host.