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What damage of bearings!Small parts also need more attention.
 

High precision roller bearings
 

Bearing is an essential part, and we often need to use bearings in order to reduce the friction coefficient and support the rotary body of the machine.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.

1.Bearing abrasion
The abrasion of the bearing is usually caused by the foreign body entering the bearing.When the foreign body enters the bearing, it will cause grinding damage, abrasion, groove mark, circular line and debris pollution.

1)Abrasion damage: when the small foreign body enters the internal bearing of the bearing, it may cause excessive abrasion of the bearing.For example, the metal particles or carbides produced in the sand, grinding and machining processes will wear or grind the roller and raceway.This kind of wear can cause the axial clearance or internal clearance to expand, thereby reducing the fatigue life of the bearing and leading to the eccentric bearing.

2)Pitting and abrasion: the hard particles are rolled inside the bearing, which can cause the pitting and abrasion of the roller and raceway.Improper cleaning of the bearing base and residual metal debris or large particle dust will lead to premature fatigue damage.

3)Grooves: groove marks are extremely serious wear caused by debris or metal particles.These pollutants are wedged into the soft material to hold the material, causing the rolling member to appear grooves, which will affect the rolling contact geometry and reduce the bearing service life.

4)clastic pollution: external clastic pollution is usually caused by dust and sand particles and the environment, while internal clastic pollution generally consists of gears, spline, sealing ring, clutch, brake, joint and bearing caused by improper cleaning or component damage or flake.The hard particles travel in the bearing with the lubrication process, which eventually causes the internal surface abrasion (compression) of the bearing.The indentation forms a protuberance, which causes the concentration of surface stress, which causes the early damage of bearing surface and reduces the bearing’s life.

2.Bearing corrosion
Erosion or corrosion is one of the most serious problems encountered in anti-friction bearings.Bearing raceway and roller surface high precision, make it extremely easy to be eroded by moisture and water..

Erosion is usually caused by the temperature change in the bearing seat, the condensation of the internal air and the accumulation of water.And the moisture or water often enters the bearing from the damaged, damaged or improper sealing ring.In addition, the bearings are removed, inspected, cleaned and dried improperly, also can cause such damage.When 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, packed with original packaging, to reduce the possibility of static corrosion before installation.

3.Underlubrication
Insufficient lubrication can be used to describe a variety of possible damage situations.The common feature of these conditions is that, in the process of bearing operation, the lubricant can not be fully separated from the surface of the bearing rolling and sliding contact.For different bearing system shall be based on experience, load, speed, sealing system, operation and life expectancy to properly design the lubricant, the dosage of type, level, supply systems, viscosity and additives, it is very important.If these factors are not considered properly, the performance of the bearing and its running performance may not achieve the desired effect.

The bearing damage caused by insufficient lubrication can be very different. It may be a very slight thermal discoloration with a large end of the roller, or it may be the overall locking of the bearing with extreme metal distortion.There is also the case that the bearing experiences dry start and is accompanied by extreme metal distortion, but the surface remains bright;This happens occasionally.This is because in the start-up phase, the bearing is damaged by heat due to contact with the metal, and then, once the lubricant reaches the bearing, the bearing eventually cools down.Then, the bearing attempts to “repair” itself to hide the original metal distortion and heat discoloration.

Secondary damage is more obvious, often masking initial problems and subsequent bearing damage.This type of bearing damage typically results in local high heat and metal flow in the bearing, thus changing the original bearing geometry and bearing material.Any visible metal crack, scratch, thermal mark, deformation or geometric change will make the bearings obsolete and will never be used again.

4.Bearing overload
Excessive preloading can produce a lot of heat and cause bearing damage.The damage form is similar to the damage 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 high preload bearing, since the strength of the oil film may not be sufficient to carry high load.

Under high preload, even with extreme pressure lubricants capable of carrying heavy loads, there may be another form of damage.Although lubricants are able to cope with loads and prevent rolling components or raceway cuts, heavy loads may result in premature fatigue and peeling in the secondary surface layer.The appearance of this type of spalling and the bearing life will depend on the preload and load capacity of the bearing.

5.Bearing operation and installation
Be careful when operating and assembling the bearings. Do not damage the rolling body, raceway surfaces and edges.If the raceway surface has a deep gouge, or if the rolling body is hit or deformed, the metal in the vicinity of the damaged area will be raised accordingly.When the rolling component passes through these damaged surfaces, it produces high stress and causes local premature peeling.The direct effect of gouging and deep indentation is to make the bearing rough and vibrate and noise.


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