What are the common damage of bearings?
- 2020/8/5 17:30:47
In mechanical equipment, bearing is an essential part, in order to reduce the friction coefficient and support the mechanical rotating body, we often need to use the bearing.But in the daily machinery and equipment in use process will often because the environmental factors and human factors lead to certain damage of the bearings, at this time we need to replace the bearing or looking for a manufacturer for repair, this undoubtedly caused a certain pressure on the cost, therefore, understand the bearing damage mechanism, clear the influencing factors on the quality of the bearing is conducive to our better use of the bearing.(HONBbearing06)
Bearing wear is usually caused by foreign matter entering the bearing interior.Foreign matter entering the bearing can cause grinding damage, abrasions, grooves, circumferential lines and debris contamination.
1. Grinding damage: When tiny foreign matter enters the bearing, excessive grinding damage may be caused.Such as sand grains, metal particles from grinding and machining processes, and metal particles or carbides from gears, can wear or grind rollers and raceways.This wear can cause the axial clearance or internal clearance to expand, which in turn reduces the bearing's fatigue life and leads to the bearing's eccentricity.
2. Pitting and bruising: Hard particles rolling in the bearing can cause pitting and bruising on the roller and raceway.Improper cleaning of bearing housing and residual metal debris or large particles of dust, will lead to premature fatigue damage.
3. Groove marks: Groove marks are extremely severe wear and tear caused by debris or metal particles.These contaminants wedge into the soft cage material and create grooves in the rolling elements, which affect the rolling contact geometry and reduce the service life of the bearing.
4. Debris pollution: External debris pollution is usually caused by dust, sand and environmental particles, while internal debris pollution is generally caused by improper cleaning of gears, splines, sealing rings, clutches, brakes, joints and bearing seats, or damage or peeling of components.The hard particles travel along the bearing during lubrication, eventually causing abrasions on the inner surface of the bearing.The indentation forms a prolongation, causes the surface stress concentration, causes the bearing surface early damage, reduces the bearing life.
Bearing erosion
Erosion or corrosion is one of the most serious problems encountered in friction resistant bearings.The high precision machining of bearing raceway and roller surface makes them vulnerable to corrosion by moisture and water.
Erosion is usually caused by the temperature change in the bearing housing, condensation of the internal air, and the accumulation of moisture.Moisture or water often enters the bearing from damaged, damaged, or improper seals.In addition, improper cleaning and drying of bearings during disassembly and inspection can also cause such damage.After the bearing is cleaned and dried, or when the bearing is placed in the warehouse, it should be coated with lubricating oil or other preservatives and packed in protective paper.Both new and old bearings should be placed in dry areas with original packing to reduce the possibility of static corrosion before installation.Bearing operation and installation
Care should be taken in the operation and assembly of the bearing to avoid damage to the rolling body, raceway surface and edges.If there is a deep gouge on the surface of the raceway, or if the rolling body is impacted or deformed, the metal near the damaged area will be raised accordingly.When rolling members pass through these damaged surfaces, high stress is generated and local premature peeling occurs.The direct effect of gouging and deep marking is to make the bearing rough and produce vibration and noise.
Insufficient bearing lubrication
Inadequate lubrication can be used to describe many possible damage conditions.A common feature of these cases is that the lubricant is not sufficiently isolated from the bearing's rolling and sliding contact surfaces during the bearing operation.For different bearing systems, it is important to correctly design the amount, type, grade, supply system, viscosity and additives of the lubricant required, based on experience, load, speed, sealing system, operating conditions and life expectancy.If these factors are not properly considered, the bearing performance and its operating performance may not achieve the desired effect.
Bearing damage due to inadequate lubrication can vary from very slight thermal discoloration with large roller scratches to integral locking of the bearing with extreme metal distortion.There is also a case where the bearing is subjected to a dry start, accompanied by extreme metal distortion, but the surface remains bright;This happens occasionally.This is because during the start-up phase, the bearing suffers heat damage due to metal-to-metal contact, and then, once the lubricant reaches the bearing, the bearing eventually cools down.The bearings then attempt to "repair" themselves to disguise the initial metal distortion and thermal discoloration.
Secondary damage is more pronounced and often conceals the initial problem and subsequent bearing damage.This type of bearing damage typically results in high local heat and metal flow within the bearing, thereby altering the original bearing geometry and material.Any visible metal crack, scratch, heat mark, deformation or geometric change will render the bearing useless and unusable.Bearing overload
Excessive preloading will generate a lot of heat and lead to bearing damage.The form of damage is similar to that caused by insufficient lubrication in appearance.These two triggers are often confused, so a thorough examination is needed to determine the root cause of the problem.Lubricants suitable for general operation may not be suitable for bearings with high pre-loads because the oil film may not be strong enough to carry ultra-high loads.
Another form of damage may occur under high preloads, even when extreme pressure lubricants capable of carrying heavy loads are used.Although the lubricant can cope with the load and prevent scratches to the rolling members or raceway, heavy load may cause premature fatigue flaking of the secondary surface layer.The occurrence of this type of spalling and the consequent bearing life problems will depend on the bearing's pre-load and bearing capacity.