Backstops are used extensively on pumps used in the primary and secondary cooling systems of power generating equipment.
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Analysis on the abnormal causes of surface shedding of needle roller bearingHave Read 31110/15/2019
A part of the material on the moving surface of the bearing falls off like a fish scale, which is called fatigue spalling. During the running process of the moving bearing, it bears a certain load, even if it is a static load, but for the steel ball and racetrack, its stress is reincarnated and reciprocating, and the material will produce dynamic fatigue so that the bearing can reach its life. In addition, there are several different definitions of bearing "life", one of which is the so-called "working life", which indicates that the actual life of a needle roller bearing can be achieved before damage is caused by wear and tear, damage is usually not caused by fatigue, but by wear, erosion, seal damage and other reasons. However, no matter in the laboratory test or in the actual use, it can be obviously seen that the bearing with the same appearance under the same working premise has a great difference in the actual life. The life revolution of a bearing (or the number of working hours at a certain speed) is defined as: a needle roller bearing within this life shall undergo initial fatigue damage (spalling or defect) on any bearing ring or moving body. Most bearings are damaged for many reasons - more than the original estimated load, not effective seal, too tight fit caused by too small bearing clearance, etc.
Each of these factors has its own special damage pattern and will leave a special damage trace. Therefore, in most cases, the possible causes of damaged bearings can be found by examining them. In general, one-third of needle roller bearings are damaged due to fatigue, the other one-third due to poor lubrication, and the other one-third due to contamination entering the bearings or improper installation. However, these types of damage are also industry-specific. For example, the pulp and paper industry is mostly due to poor lubrication or pollution caused by bearing damage rather than due to material fatigue.
Major metal noise reason 1: abnormal load, countermeasures: modify coordination, study bearing clearance, adjust and load, modify the position of shell retaining shoulder. Reason 2: poor installation, countermeasures: shaft, shell processing accuracy, improve the installation accuracy, installation method. Reason 3: insufficient or unsuitable lubricant. Countermeasures: supplement lubricant and choose appropriate lubricant. Reason 4: rotating parts have contact, countermeasures: modify the contact part of curved road seal. Reason 1: because the foreign body causes the rolling surface to produce the indentation, the rust or the scar, the countermeasure: changes the bearing, the cleaning related part, improves the sealing device, USES the clean lubricant. Reason 2: (after steel carburizing) surface deformation, countermeasures: replace the bearing, pay attention to its use. Reason 3: raceway surface peeling, countermeasures: replace needle roller bearing.
Irregular noise reason 1: clearance is too large, countermeasures: research coordination and bearing clearance, modify the pre-load. Reason 2: foreign body invasion, countermeasures: study to replace the bearing, clean the relevant parts, improve the sealing device, use clean lubricant. Reason 3: spherical injury, peel, countermeasures: replace the bearing. Abnormal temperature rise reason 1: excessive lubricant, countermeasures: reduce lubricant, appropriate amount of use, choose a harder grease. Reason 2: insufficient or unsuitable lubricant. Countermeasures: supplement lubricant and choose appropriate lubricant. Reason 3: abnormal load. Countermeasures: modify the coordination, study the clearance of the bearing, adjust the pre-load, and modify the position of the retaining shoulder of the shell. Reason 4: poor installation. Countermeasures: improve the machining accuracy, installation accuracy and installation method of shaft and shell. Reason 5: creep of mating surface and excessive friction of sealing device. Countermeasures: replace needle roller bearing, study coordination, modify shaft and shell, and change sealing form. Reason 1: (after steel carburizing) surface deformation, countermeasures: pay attention to bearing replacement operation. Reason 2: stripping, solution: replace the bearing. Reason 3: poor installation, countermeasures: modify the shaft, shell shoulder right Angle, liner side straight Angle. Reason 4: foreign body invasion, countermeasures: replace the bearing, clean the parts, improve the sealing device. Excessive lubricant leakage, discoloration reasons: excessive lubricant, foreign matter invasion, wear powder produced foreign matter, etc. Countermeasures: appropriate use of lubricant, research on the choice of lubricant, research on the replacement of needle roller bearing, cleaning the shell.