In mechanical operations, bearings are a very common component. In daily use, it is inevitable that you will encounter various problems. How to avoid bearing failure? The following content summarizes the matters needing attention in the use of several bearings for you:
Precautions for the use of bearings
1. Bearing contact fatigue failure
Contact fatigue failure refers to the failure of the bearing working surface under the influence of alternating stress. Contact fatigue spalling occurs on the working surface of the bearing, usually accompanied by fatigue cracks. First, it is generated from the maximum alternating shear stress below the contact surface, and then extends to the surface to form different peeling shapes, such as pitting or pitting peeling, and peeling into small pieces is called shallow peeling. As the peeling surface gradually expands, it often expands to the deep layer, forming deep peeling. Deep spalling is the fatigue source of contact fatigue failure.
2. Bearing wear failure
Abrasion failure refers to the failure in which the relative sliding friction between the surfaces causes the continuous wear of the metal on the working surface. Continuous wear will gradually damage the bearing parts, eventually leading to related problems such as loss of bearing dimensional accuracy. Abrasion may affect the shape change, increase the gap, and change the shape of the working surface, and may affect the lubricant or pollute it to a certain extent, resulting in complete loss of lubrication function, loss of rotational accuracy of the bearing, or even failure to work properly. Wear failure is one of the common failure modes of various bearings. According to the wear form, it can be divided into the most common wear and adhesive wear.
Abrasive wear refers to the wear caused by foreign hard particles or hard foreign matter or metal surfaces being squeezed into the working surface of the bearing, and the relative movement of the contact surface, often causing furrow-like scratches on the working surface of the bearing. Hard particles or foreign matter may come from the inside of the main engine or other adjacent parts of the main engine system, and are sent into the bearing by the lubricating medium. Knowledge about bearing accuracy errors. Adhesive wear refers to uneven stress on the friction surface due to obvious protrusions or foreign objects on the friction surface. When the lubrication conditions are severely deteriorated, heat is generated due to local friction, which easily leads to local deformation and friction micro-welding of the friction surface. In severe cases, the surface metal may be partially melted, and the force of the contact surface tears the local friction solder joints from the substrate, increasing plastic deformation. This cyclical process of bonding, tearing, and bonding constitutes bonded wear. Generally speaking, slight adhesive wear is called galling, and severe adhesive wear is called undercut.
3. Bearing fracture failure
The main causes of bearing fracture failure are defects and overload. When the external load exceeds the strength limit of the material, the part fracture is called overload fracture. The main reason is that the host suddenly fails or is improperly installed. Defects such as microcracks, shrinkage cavities, air bubbles, large foreign objects, overheated tissues, and local burns of bearing parts will also cause defect fractures under impact overload or severe vibration, which is called defect fracture. It should be pointed out that during the manufacturing process, bearings can be re-inspected on raw materials. Quality control of forging and heat treatment. In the process control, the instrument can correctly analyze whether the above-mentioned defects exist, and the control must be strengthened in the future. But generally speaking, bearing fracture failure is mostly overload failure.
4. Bearing clearance change failure
In the bearing work, due to the influence of external or internal factors, the original fit clearance changes, the accuracy is reduced, and even the seizure is called a clearance change fault. External factors, such as interference, improper installation, expansion caused by temperature rise, instantaneous overload, etc. Intrinsic factors, such as retained austenite and residual stress instability, are the main reasons for gap variation failure.