(6). Card injury
The card-injury is a surface damage caused by a combination of minute burns in a portion of the sliding surface damage. Linear scratches on the surface of the slideway and the circumferential surface of the rolling surface. A pendulum-like flaw on the end face of the roller and a jam on the collar face near the end face of the roller. The main causes of the card injury are: excessive load, excessive preload, poor lubrication, foreign matter biting, inclination of the inner ring outer ring, shaft deflection, shaft and bearing box accuracy.
It can be solved by properly pre-pressing, improving the lubricant and lubrication method, and improving the accuracy of the shaft and bearing housing.
Wear failure refers to the failure of the relative sliding friction between the surfaces resulting in the continuous wear of the metal on the working surface. The main factors causing wear and tear are lubricant failure or lack of lubricant. The lubrication method is not correct. There are abrasive grains entering the bearing and the load is too large. The solution can be enhanced by improving the lubricant or improving the lubrication method.
The so-called abrasion is a surface damage which occurs on the raceway surface and the rolling surface with a summary of minute burns caused by rolling slip and oil film thermal cracking. Produces a rough surface with adhesion. The main causes of abrasions are high-speed light load, rapid acceleration and deceleration, improper lubricant, and water intrusion.
Solution: Improve preload, improve bearing clearance, use oil film lubricant, improve lubrication method, and improve sealing device.
When a small metal powder or foreign matter is bitten, a dent formed on the raceway surface or the rotating surface or a shock due to the installation causes a concave surface (Brinell hardness indentation) at a pitch interval of the rolling elements. The main factors causing the indentation are: foreign matter such as metal powder biting, excessive impact load during assembly or transportation.
Solution: Improve the sealing device, filter the lubricant, improve the assembly and use methods.
The raceways, rolling elements, and cages rapidly heat up during rotation until discoloration, softening, welding, and breakage. The causes of burns are poor lubrication, excessive load (pre-pressure is too large), excessive speed, too small clearance, intrusion of water and foreign matter, poor precision of the shaft and bearing housing, and large deflection of the shaft.
It can be solved by improving the lubricant and lubrication method, correcting the choice of bearings, researching the fit, bearing clearance and preload, improving the sealing device, checking the accuracy of the shaft and bearing housing or improving the installation method.
(11). Current corrosion
The so-called electric erosion means that when a current flows in the rotating contact portion of the bearing ring and the rolling element, a spark is emitted through the thin lubricating oil film, and local melting and unevenness appear on the surface. The main cause of galvanic corrosion is the potential difference between the outer ring and the inner ring and the action of static electricity.
Solution: When setting the circuit, the current does not pass through the bearing, the bearing is insulated, and the static ground.
(12). Rusty corrosion
The rust and corrosion of the bearings have raceways, pit rust on the surface of the rolling elements, and overall rust and corrosion. The rust and corrosion of the bearing will cause the pit rust on the surface of the ferrule and the rolling element, the pit-like rust and the same crater rust, full rust and corrosion. There are many reasons for the failure of rolling bearing rust corrosion, mainly: intrusion of water, corrosive substances (lacquer, gas, etc.), improper lubricant, water droplets due to condensation of water vapor, stop at high temperature and humidity, transportation process The rust prevention is poor, the storage state is not suitable, and the use is not suitable.
The solutions are: improving the sealing device, studying the lubrication method, anti-rust measures when stopping, improving the storage method, and paying attention when using it.
In addition to the above-mentioned common failure modes, there are still many failure modes of rolling bearings in actual operation, which needs further analysis and research. In summary, from the common failure mechanism and failure mode of the bearing, although the rolling bearing is a precise and reliable mechanism base, improper use can cause early failure.
In general, if the bearing can be used correctly, it can be used until the fatigue life. The early failure of the bearing is caused by the manufacturing precision, installation quality, use conditions, lubrication effect, external foreign matter intrusion, heat influence and sudden failure of the host.
Therefore, the correct and reasonable use of the bearing is a systematic project. In the process of bearing structure design, manufacturing and installation, corresponding measures are taken for the early failure, which can effectively improve the service life of the bearing and the main engine.