Precautions to avoid Timken bearing failure
Precautions to avoid Timken bearing failure
2022年4月14日
Lubrication mode of Koyo bearing and manufacturing principle of operation
Lubrication mode of Koyo bearing and manufacturing principle of operation
2022年4月15日

Inspection and Disposal of Faults in Bearing Operation

1、 Rolling sound of bearing

  • Select a sound detector to check the size and sound quality of the rolling sound of the bearing during operation; Even if the bearing has slight peeling and other damage; Abnormal sounds and irregular sounds will also be announced; It can be distinguished with a sound detector

2、 Bearing oscillation

  • Bearing oscillation is very sensitive to bearing damage; For example, falling off, indentation, corrosion, crack and wear will be reflected in the measurement of bearing oscillation; So;Inspection and Disposal of Faults in Bearing Operation
  • The values measured by a special bearing oscillation meter (frequency analyzer, etc.) are different due to the application conditions of the bearing or the orientation of the sensor device; Therefore, it is necessary to analyze and compare the measured values of each machine in advance and determine the criterion

3、 Temperature of bearing

  • Temperature of bearing; Usually, the temperature outside the bearing chamber can be estimated; If the oil hole is used, the temperature of the bearing outer ring can be measured directly; Is more suitable Usually;Inspection and Disposal of Faults in Bearing Operation
  • The temperature of the bearing rises gradually with the beginning of operation; Inspection and Disposal of Faults in Bearing Operation
  • Arrive at safe and stable condition after 1-2 hours The normal temperature of the bearing is due to the thermal capacity of the machine; Heat dissipation;Inspection and Disposal of Faults in Bearing Operation
  • The speed and load are different If it is smooth and the device part is suitable; The bearing temperature will rise sharply; Abnormal high temperature will occur; It is necessary to stop the operation at this time; Take necessary precautions Based on a lot of test data;Inspection and Disposal of Faults in Bearing Operation
  • Because the temperature is affected by smoothness, speed, load and environment; The operating temperature of the bearing can be monitored at any time by using the thermal sensor; When the temperature exceeds the regular value, it will actively alarm the user or stop to avoid the occurrence of combustion shaft accident.Inspection and Disposal of Faults in Bearing Operation

4、 Smooth

  • Smoothness has an important influence on the fatigue life, conflict, wear, temperature rise, oscillation and so on; Not normally smooth; The bearing will not work Analyze the cause of bearing damage and mark it; About 40% of bearing damage is related to poor smoothness Therefore;Inspection and Disposal of Faults in Bearing Operation
  • The excellent smoothness of bearings is a useful way to reduce bearing conflict and wear besides; Smooth bearing and heat dissipation; Rust prevention, sealing, gentle impact and other effects; The effect of bearing smoothness can be briefly explained as follows:Inspection and Disposal of Faults in Bearing Operation

Inspection and Disposal of Faults in Bearing Operation

  •   An oil film is formed between the two rolling surfaces or sliding surfaces touching each other to separate the two surfaces; Cut the conflict and wear of touch appearance
  •   When smooth oil is selected; Especially when the circulating oil is smooth, the oil mist is smooth and the fuel injection is smooth; Smooth oil can take away most of the heat inside the bearing; Play a useful heat dissipation effect
  •  When the grease is smooth; It can prevent foreign matters such as external dust from entering the bearing; Play a closing effect
  •  All the agents have the effect of avoiding metal corrosion
  •   Fatigue life of extension bearing
  •   Make up interval of smooth grease
  • Because of the mechanical effect; Aging and pollution addition; The smooth base filled in the bearing equipment will gradually lose its smooth function Therefore; The smooth rank needs to be continuously compensated and updated The interval time of smoothing agent compensation will be different due to the composition, scale and speed of the bearing; The approximate interval time to replenish the smooth grease according to the operation time demand other; Inspection and Disposal of Faults in Bearing Operation
  • When the bearing temperature exceeds 70 ℃; Every 15 ℃ rise in bearing temperature; It is necessary to use smooth grease to reduce the interval by half The double-sided closing bearing has been filled with grease during manufacture; “HRB” uses standard smooth grease in these products; Common working temperature scale and other functions are suitable for the regulated occasions; And the grease filling amount is also corresponding to the size of the bearing; The service life of grease can usually exceed that of bearing; Except for special occasions; There is no need to replenish the grease.Inspection and Disposal of Faults in Bearing Operation.Inspection and Disposal of Faults in Bearing Operation
  •   Replacement cycle of smooth oil
  • The replacement cycle of smooth oil is different due to application conditions and oil volume; Under normal circumstances; Operating temperature below 50 ℃; When used in an excellent environment with less dust; Replace once a year; When the oil temperature reaches 100 ℃; It needs to be replaced every three months or less.Inspection and Disposal of Faults in Bearing Operation
Inspection and Disposal of Faults in Bearing Operation
  • The judgment criteria vary according to mechanical properties, importance and inspection cycle. In case of the following damage, the one-way thrust ball bearing shall not be reused and must be replaced. In the process of using bearings, grease is very critical. If deteriorated grease is used, it will not only fail to play its due role, but also damage the bearing.Generation and Elimination of Noise of One-Way Thrust Ball Bearing

Generation and Elimination of Noise of One-Way Thrust Ball Bearing

  • Twist the lubricating oil between the thumb and index finger and grind it repeatedly. The better lubricating oil hand feels lubricity, less wear debris and no friction. If it feels a large friction feeling such as sand particles between the fingers, it indicates that there are many impurities in the lubricating oil and it can not be used again. It should be replaced with a new lubricating oil.Generation and Elimination of Noise of One-Way Thrust Ball Bearing
  • Raceway sound of one-way thrust ball bearing and its control method raceway sound is a smooth and continuous sound made by the rolling body rolling on the raceway surface when the one-way bearing is running. It is a unique basic sound that will occur in all rolling bearings. The general bearing sound is the sound of raceway plus other sounds. The raceway sound of ball bearing is irregular, and its frequency is above 1000Hz. Its main frequency does not change with the speed, but its total sound pressure level increases with the speed.Generation and Elimination of Noise of One-Way Thrust Ball Bearing
  •  For the bearing with loud raceway sound, the sound pressure level of raceway sound decreases with the increase of viscosity; For bearings with low raceway noise, the sound pressure level changes from decrease to increase when the viscosity increases to more than 20mm2 / s. The lower the sound level of the bearing, the greater the total sound pressure of the bearing.Inspection and Disposal of Faults in Bearing Operation
  •  If the radial clearance is too small, the total sound pressure level and dominant frequency of raceway sound will increase sharply with the decrease of radial clearance. The methods to control the sound of raceway are: select low-noise bearings, that is, bearings with small waviness, and carefully select the service conditions. Raceway noise often affects the noise of the whole machinery. Reducing raceway noise can reduce the noise of the whole machinery.Generation and Elimination of Noise of One-Way Thrust Ball Bearing
  • The metallurgical quality of unidirectional thrust ball bearing material was once the main factor affecting the early failure of bearing. With the improvement of Metallurgical Technology (such as vacuum degassing of bearing steel), the quality of raw materials has been improved. The proportion of raw material quality factor in bearing failure analysis has decreased significantly, but it is still one of the main influencing factors of bearing failure. Proper material selection is still a factor that must be considered in bearing failure analysis.Generation and Elimination of Noise of One-Way Thrust Ball Bearing
  • The main task of failure analysis of one-way thrust ball bearing is to find out the main factors causing bearing failure according to a large number of background materials, analysis data and failure forms, so as to put forward targeted improvement measures, prolong the service life of self-aligning roller bearing and avoid sudden early failure of bearing.Inspection and Disposal of Faults in Bearing Operation
  • The vibration of one-way thrust ball bearing has a significant effect on the failure of bearing. For example: peeling, indentation, corrosion, crack Wear, etc. will be reflected in the bearing vibration detection, so the vibration can be measured by using special bearing vibration measurement devices (frequency analyzer and vibration instrument, etc.), and the details of abnormal vibration can be inferred from the frequency distribution. The measured values are different due to the use premise of the bearing or the installation position of the sensor. Therefore, it is necessary to analyze and compare the measured values of each machine in advance and determine the judgment scale.Inspection and Disposal of Faults in Bearing Operation
  •  Cause: the inner shell of the bearing runs. Method: replace the bearing and related worn parts
  •  Cause: poor lubrication method: select the specified brand of lubricating materials and clean them properly
  •  Cause: the belt is too tight. Method: adjust the belt to make it elastic properly
  •  Cause: the main shaft is bent or the box hole is not concentric. Method: repair the main shaft or box
  •   Cause: low assembly quality method: improve assembly quality
  •   Cause: low bearing accuracy method: select the bearing with specified accuracy grade
  •  Method of excessive axial force: clean and adjust the clearance of sealing ring between 0.2 ~ 0.3mm, correct the diameter of impeller balance hole and verify the static balance value
  •  Bearing damage method: replace the bearing
  • The methods of bearing smoothing are roughly divided into grease smoothing and oil smoothing In order to give full play to the function of the bearing; The important thing is based on the application reduction and application intention; Choose a smooth method
  • Smooth grease is made of base oil; A smoothing agent composed of thickener and additives When selecting; The lubricating grease that is very suitable for the service conditions of the bearing shall be selected; Because the trademarks are different; There will also be great differences in function; Inspection and Disposal of Faults in Bearing Operation
  • So when choosing; It is necessary to pay attention The commonly used smooth grease of bearings includes calcium base smooth grease, sodium base smooth grease, calcium sodium base smooth grease, lithium base smooth grease, aluminum base smooth grease and molybdenum disulfide smooth grease Quantity of smooth grease filled in the bearing; It is suitable to fill 1 / 2-1 / 3 of the internal space of the bearing At high speed, it should be reduced to 1 / 3 Too much grease raises the temperature.Inspection and Disposal of Faults in Bearing Operation
  • When selecting smooth grease according to operating temperature; The primary goal should be drip point; Oxidation stability and low temperature function; The drop point can usually be used to evaluate the high temperature function;Inspection and Disposal of Faults in Bearing Operation
  •  The practical operating temperature of the bearing shall be 10-20 ℃ lower than the dropping point The application temperature of the composition smooth grease shall be 20-30 ℃ lower than the dropping point When selecting smooth grease according to bearing load; Inspection and Disposal of Faults in Bearing Operation
  • A smooth needle with a small load When working under high pressure, except for small penetration; It also has high oil film strength and extreme pressure function When selecting smooth grease according to environmental conditions; Calcium based smooth grease is not easily soluble in water; Suitable for dry and less moisture environment
  • At high speed and high temperature; When the grease is no longer suitable, oil can be used for smoothing After smooth oil circulation; Can take away a lot of heat
  • Viscosity is an important characteristic of smooth oil; The size of viscosity directly affects the fluidity of smooth oil and the thickness of oil film formed between conflict surfaces; The viscosity of smooth oil at bearing operating temperature is usually 12-15cst The higher the rotating speed, the lower the viscosity should be selected; The heavier the load, the higher the viscosity should be selected Commonly used smooth oil includes machine oil, high-speed machine oil, turbine oil, compressor oil, transformer oil, cylinder oil, etc.Inspection and Disposal of Faults in Bearing Operation
  • The oil smoothing method includes:Inspection and Disposal of Faults in Bearing Operation
  •   Oil bath smooth.Inspection and Disposal of Faults in Bearing Operation
  • Oil bath smoothing is the usual smoothing method; Suitable for smooth of low and medium speed bearings; Part of the bearing is immersed in the groove; The smooth oil is carried by the rotating bearing parts; Then it flows back to the oil groove, and the oil level should be slightly lower than the middle of the low tumbling body
  •   Oil dripping smooth.Inspection and Disposal of Faults in Bearing Operation
  • The oil dripping is smooth, which is suitable for the bearing parts requiring quantitative supply of smooth oil; The amount of oil drop is usually one drop every 3-8 seconds; Too much oil will cause the bearing temperature to rise.Inspection and Disposal of Faults in Bearing Operation
  •   Smooth circulating oil
  • Use the oil pump to deliver the filtered oil to the bearing parts; The smooth oil after bearing is filtered and cooled before use Because the circulating oil can take away certain heat; Cool the bearing; Therefore, this method is suitable for bearing parts with high speed.Inspection and Disposal of Faults in Bearing Operation
  •   Spray smoothing
  • The oil mist is formed by mixing the dry compressed air with the smooth oil through the sprayer. In the bearing; The air flow can effectively cool the bearing and avoid the invasion of impurities This method is suitable for the smoothing of high speed and high temperature bearing parts.Inspection and Disposal of Faults in Bearing Operation.Inspection and Disposal of Faults in Bearing Operation
  •   Smooth eruption
  • Use the oil pump to shoot the high-pressure oil into the bearing through the nozzle; The oil injected into the bearing flows into the oil groove through the other end of the bearing When the bearing rotates at high speed; The tumbling body and the cage also make the surrounding air form an air flow at an appropriate high rotation speed; It is difficult to send the smooth oil to the bearing by the usual smooth method; At this time, it is necessary to spray the smooth oil into the bearing by means of high-pressure eruption; The nozzle should be oriented between the inner ring and the cage Under some special application conditions;Inspection and Disposal of Faults in Bearing Operation
  •  A few solid smoothing agents are added to the smoothing grease; If 3 ~ 5% molybdenum disulfide 1 is added, the wear can be reduced; Improve the ability of compression and heat resistance; About high temperature, elegance, high vacuum, corrosion resistance and radiation resistance; Inspection and Disposal of Faults in Bearing Operation
  • extreme low temperature and other special conditions; Adding solid smoothing agent into engineering plastics or powder metallurgy materials; It can be made into bearing parts with self smoothing function; If the solid smoothing agent is bonded to the raceway, cage and rolling body with adhesive; Form a smooth film; It has a certain effect on reducing conflict and wear.Inspection and Disposal of Faults in Bearing Operation