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Bearing premature aging cause equipment downtime, now combined with the author of the motor repair practices, introduced to prevent premature bearing the experience of aging. SKF bearings prematurely aging: with tight, poor lubrication, installation not, strong vibration, material fatigue, pollution corrosion.
1 with tight
The ring trajectory into the journal when the FAG bearings inner ring sets mandatory, the light will make the bottom of the raceway serious wear, heavy in the slide on the outer ring and ball are particularly cracks or peeling. The reason: a ball and slide gap is to cut through the small increase in torque, friction increases, the bearing operating temperature is too high, and failure of the bearing wear and fatigue exacerbated.
Prevent: Restore the radial clearance of the bearing, reducing the amount of interference.
There are two bearing assembly quality inspection methods:
Visual method: When the motor cover bearing chamber mounted on bearings, hand rotating end cap, NSK bearings rotate freely, flexible, no vibration and shaking up and down phenomenon, are considered qualified.
The feeler Act: TIMKEN bearings of the motor will be equipped with end cap assembly base ended mouth with 0.03mm thick feeler bearing radial clearance of the week, the maximum gap position just in the middle of the top of (the motor horizontal installation) is assembled correct, reliable, and otherwise, is a poor installation. Cover position should be appropriately adjusted, reassembled, until qualified.
2. Poor lubrication
Due to a serious lack of grease or fat dry aging. Friction and heat motor speed operation, resulting in excessive bearing temperature oxidation discoloration, performance ball INA bearings, cage, inner ring and its journal, etc. become brown or blue.
Prevent Methods: According to the four factors of the motor run time, ambient temperature, load status, grease good or bad, up the oil and oil change time. Under normal circumstances, the motor running 6000 to 10000h should fill oil; running 10000 ~ 20000h should change the oil, 2-pole or 4-pole motor change oil bearing chamber volume of 1/2 to 2/3, and quality lithium grease (code ZL-2) should be used.
3. Installation is not in
If the installation is not in, not only bearing slide bead marks and ball uneven wear marks, also produced skewed, with a feeler bearing on both sides of the radial gap ranging, and quite different. Probably because iron hammer percussion bearing outer ring; belt pull (the gear meshing) is too tight; parallel to the driving wheel and passive wheel centerline. When its deflection greater than 1/1000, will cause the bearing operating temperature is too high, badly worn slides and ball, shaft bending and cover bolts clamping surface is not perpendicular to the bolt axis.
Proper installation method: steel pipe sleeve with the end surface smooth, almost equal to the thickness of the bearing inner ring, the bearing pressure in the clean and journalled on the correct position. Press-fitting force should be uniform, can not be too fast. Then allow radial different motor speed check shaft end runout value.
4. Strong vibration
Strong vibrations cause bearing failure in the motor core. Reasons: core thermal deformation; the motor bearings aging; the shaft bending deformation; cover the mouth tighten bolts loosening due to vibration; sturdy foundation bearing vibration.
To prevent: core car soak silicon steel sheet surface and opened the gap with silicone varnish 1052; replace with new models bearing; exit rotor core alignment shaft curved portion; 180 ° symmetry method; tighten the end cap rabbet bolts; reinforced foundation, tighten the anchor bolts.
5. Material fatigue
Metal Fatigue bearing raceway and ball surface shedding fractal mixed in grease will make it work noise increases, the ball was sliding bearing radial clearance increased, and the diameter of shaft end allows 2 to 3 times to the increased value of the yaw. Bearing a degree of fatigue decision factors include: the load of the motor speed, the air gap, the end cap type, the toughness of the material, grease quality grease retrofitting amount.
Prevent Methods: According to the records of the motor is running, light duty work of more than 60% of the rated current, running to 2000 ~ 25000h, medium-load current rating of 60% to 80% run to 15000 ~ 20000h heavy duty operating current 80% to 100% of rated running to 10000 ~ 15000h, should be considered the normal fatigue of the bearing material, replace with new models bearing.
6. Pollution corrosion
In this case, the raceway and ball surface appeared red, brown blotchy corrosion, increased work noise compared with the sound of the new bearing.
The reason is dirty the place of assembly, if presence of water, gas, acid, alkali and toxic gases; tools and hand pollution; using the poor quality of the lubricating means.
Preventing method: assembly bearings are required to keep the environment clean tools and in; wash bearings thoroughly; replacement of quality lithium grease.
| Product Model | Inside Diameter | Outside Diameter | Thickness |
| 7203ATYNDBLP4 NSK | 17 | 40 | 12 |
| 7203A5TYNDBLP4 NSK | 17 | 40 | 12 |