Self-aligning ball bearing premature aging caused by equipment downtime is now combined with the author's motor repair practice, describes the experience of preventing premature aging of SKF bearings. Self-aligning ball bearings cause of premature aging are: poor fit too tight, lubricated, install, strong vibration, material fatigue is not corrosion, pollution, and so on.
　　1. tie too tight
　　Force sets in when the SKF bearing inner ring shaft the back of the neck, bottom light will enable Raceway have serious wear the ring track, severe cases in the chute on both inner and outer rings and balls have cracks or peeling. Reason: ball and ramp space was too small, the torque increases, friction increased bearing temperature is too high, bearing wear and fatigue failure.
　　Prevention method: restoration of radial clearance of bearings, reducing the amount of interference.
　　Bearing Assembly quality inspection method, there are two:
　　Visual method: when the motor after end cap bearings fitted with bearings, when turning the end cap with her hands, if the bearing rotates freely, flexible, no phenomena of vibrations and shaking up and down, as qualified.
　　Examiner test: motor equipped with SKF bearings on the end cap Assembly on the frame rabbet, 0.03mm thick examiner checks self-aligning ball bearings radial clearance of the week, when the maximum gap above the location just in the middle (motor horizontal installation), then to assemble accurate, reliable, or are installing bad. Appropriate adjustments should cover location, reassembled until qualified.
　　2. poor lubrication
　　Due to the serious lack of grease or oils dry aging. Because of motor high speed operation friction heat build-up, resulting in self-aligning ball bearing high temperature oxidizing discoloration, manifested in the SKF ball, cage and inner ring of the bearing and axle journal, brown or blue.
　　Prevention: according to the motor's running time, ambient temperature, load, lubrication grease 4 factors such as good or bad, determine their effect oil and oil change time. Under normal circumstances, the motor should run 6000~10000h oil Supplement 1 running 10000~20000h should be 1 oil change, 2-pole and 4-pole motor oil change capacity of bearing Chamber volume above 1/2~2/3, and should be made of high quality lithium base grease (code ZL-2).
　　3. install that does not appear on the
　　If the installation is not on, not only bearing slide bead marks, and ball wear signs of unevenness, skewed, check with feeler self-aligning ball bearings radial clearance on both sides will be ranging, and larger differences. Possibly with an iron hammer direct percussion bearing outer ring; belt pull (occlusal gear) is too tight; the active and passive rounds is not parallel to the center line. When when the deviation is greater than one-one thousandth, will result in SKF bearing operating temperature is too high, slide and ball badly worn, hinge bending and end cover bolt clamping surface perpendicular to the bolt axis does not.
　　The correct installation method: face smooth, with almost equal the thickness of the inner ring of the bearing steel pipe sleeves, clean axle journal bearing in the correct location. When pressure exertion should be even, not excessive. Then press the motor in speed checks allow tilting of the shaft end radial value.
　　4. strong vibrations
　　When there is a failure when the motor core, self-aligning ball bearings strong vibration. Reason: core heat deformation; motor bearing ageing; larger hinge bending; cover mouth tighten the bolts loose due to vibration; solid foundation bearing vibration.
　　Prevention method: core vehicles small, Silicon organic silicon steel sheet surface varnish 1052 immersion and opened the gap; replace the model with the new SKF bearings, exit straightening bent hinge rotor core parts; 180 degree symmetry; tightening the end cap bolts; reinforced base and tighten the bolts.
　　5. the material fatigue
　　Due to metal fatigue, raceways and balls surface detachment of irregular fragments mixed in grease, makes the noise increases, the ball is sliding, resulting in self-aligning ball bearings radial clearance increases, allows radial and shaft end swing value increases the 2~3 times. SKF bearing fatigue determinants include: load, speed, motor Air gaps, cover type, toughness of materials, quality content of lubricating grease and grease.
　　Prevention: according to motor running records, when load current is 60% more than the rated value, run to 2000~25000h, Middle 60%~80% of nominal load current is run to 15000~20000h, heavy-load current to the rated value of work 80%~100% after running into the 10000~15000h, self-aligning ball bearing material should be considered normal fatigue, replace the model with the new bearings.
　　6. pollution of corrosion
　　At this point, the road roller and ball-like red, brown spots appear on the surface corrosion, and new bearing noise compared to the sound of work increases.
　　Because the Assembly places clean, such as moisture, acids, alkalis and toxic gases; hand tools and pollution; using the inferior quality of lubrication.
　　Prevention method: assembling SKF bearings keep environment, tools and clean; ball bearings with cleaning thoroughly; replacing high quality lithium base grease.

 


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