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Premature aging of rolling bearing analysis


Premature aging of rolling bearings will cause the device to shut down, is now combined with the author's motor maintenance practices, describes the experience of preventing premature aging of rolling bearings. Causes of premature aging of rolling bearings: fits tight, poor lubrication, installation is not pollution, strong vibration, material fatigue, corrosion and so on.
  1. tie too tight
  When forced into the inner ring of the bearing shaft, the light bottom has serious wear of the roller ring track, severe cases in the chute on both inner and outer rings and balls have cracks or peeling. Cause: the clearance between ball and ramp is pressed too small, increase torque, friction increases bearing operating temperature is too high, wear and fatigue failure of the bearing.
  Prevention: restoration of radial clearance of bearings, reducing the degree of interference.
  Bearing quality inspection in two ways:
  Visual method: when after the motor end cap bearings fitted with bearing by hand when you turn the end cap, if the bearings rotate freely, flexible, vibration-free and up and down, considered OK.
  Feeler gauges check law: fitted with bearings on the motor cover Assembly to the motor stops the mouth of, 0.03mm thick feeler gauges check bearing radial clearance one week, when the maximum clearance position just above the median (motor horizontal installation), then assemble accurate, reliable, or is installed properly. Appropriate adjustments should cover position, reassemble until qualifying.
  2. poor lubrication
  Due to the serious lack of grease or oils dry aging. Because of motor high speed friction heat, bearing high temperature and oxidation to color, form of ball bearings, cage, inner ring and shaft into a brown or blue.
  Prevention method: according to the motor's running time, ambient temperature, load, lubrication grease 4 factors such as good or bad, determine their fill oil and oil change time. Under normal circumstances, the motor should run 6000~10000h oil Supplement 1; run 10000~20000h oil change 1, 2-pole or 4-pole motor to change the oil the bearing Chamber volume above 1/2~2/3, and should be made of high quality lithium base grease (code number ZL-2).
  3. the installation is not
  If not, you not only bearing bead marks on slides and ball uneven wear and tear marks, skewed, when radial clearance with a feeler gauge to check the bearings on either side of the range, and a larger difference. Because the account directly with hammer tapping the bearing outer ring; belt pull (occlusal gear) too tight; active and passive rounds are not parallel to the center line. When the deviation is greater than being one-one thousandth, will cause the bearing operating temperature is too high, slide and ball severely worn, shaft bending and end cap bolt clamping surface perpendicular to the axis of the bolt is not.
  Correct installation method: the face is smooth, with almost equal bearing inner ring thickness steel sleeve, clean shaft bearings on the correct position. Pressure should be even when they cannot be too hard. Then press the motor shaft end radial speed check allows swing value.
  4. strong vibration
  When the motor core failure, bearing a strong vibration. Reason: core thermal deformation; ageing of the motor bearings; hinge bending deformation of large end cap stops the mouth tighten bolt by vibration loosening infrastructure: no substantial bearing vibration.
  Prevention: core is small, Silicon-organic silicon steel sheet surface varnish 1052 immersion and open the cracks; replacement of the same model new bearings; exit straightening bent a shaft of rotor core part 180-degree symmetry; tighten end cap bolt reinforced base and tighten the anchor bolts.
  5. the material fatigue
  Because of metal fatigue, ball surface raceways and shedding of irregular fragments mixed in grease, the noise will increase, ball is sliding, resulting in increased radial clearance of bearings and shaft end radial increase swing allowed two or three times. Determinants of bearing fatigue include: motor load, speed, Air gaps, cover type, the toughness of the material, quality grease and grease filling.
  Prevention method: according to the motor run record when more than light duty 60% of current to the rated value, run to 2000~25000h, medium-load operating current to the rated value 60%~80% run to 15000~20000h, heavy-load operating current to the rated value after running 80%~100% to 10000~15000h, shall consider the normal fatigue of bearing materials, replacement of the same model and new bearings.
  6. pollution of corrosion
  At this point, roller and ball of red and brown spots that appear on the surface corrosion, noise increases compared to the noises of work with a new bearing.
  Because the Assembly places clean, such as water, acid, alkali and toxic gases; hand tools and pollution using the inferior quality of lubrication.
  Prevention: assembling bearings to purifying the environment, tools, and the; wash bearings thoroughly; replaced with quality lithium base grease.

 

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