1. lubricating oil or grease varieties selected a wrong;
2. lack of lubrication (oil level is too low, oil or grease leakage through seal);
3. the fag bearing clearance is too small (with select is inappropriate);
4. mixed with sand or carbon particles and other impurities in the bearings, abrasive role to play;
5. bearing mixed in with water, acid or paint, dirt, corrosion;
6. the bearing bore of clamp flat (bad bore roundness, or bore distortion is not straight);
7. the bearing surface of the pad at the end of inequality (leading to even crack the housing bore deformation);
8. the bearing block hole of a debris (residual chips, dust, etc);
9. seal eccentricity (hit neighboring parts and friction);
10. subject to additional bearing load (bearings axial Pidgin adapter, or an axis has two fixed ends bearing);
11.INA bearings and shaft tie too loose (shaft diameter too small or adapter sleeve tighten);
12. bearing internal clearance is too small, too tight when you rotate (adapter sleeve tighten too far);
13. bearing noise (end of roller or ball skidding caused);
14. the thermal elongation of the shaft is too large (attachment of statically indeterminate to bearing loads);
15. the shoulder is too large (touch the bearing seals and friction);
16. bore abutments are too large (touch distort bearing seals);
17. the labyrinth sealing ring the gap is too small (and shaft friction);
18. bent the tooth lock washer (touch the bearing and friction);
19. oil rings's position is not suitable (touch the flange cover and friction);
20. pressure on the ball or roller (installed with a hammer bearing the cause);
21.Timken bearing noise (vibration sources outside interference);
22. heat discoloration and deformation of bearing (use gun heating caused by disassembling bearing);
23. the shaft so rough that the actual tie too tight (bearing temperature is too high or caused noise);
24. the diameter of the hole is small (causing the bearing temperature is too high);
25. the bearing bore diameter is too large, the actual tie too loose (temperature is too high-the outer ring of bearings slipping);
26. the housing bore larger (bore non-ferrous metal stretch, or larger due to thermal expansion);
27. bearing noise (bearing a micro abrasive).
(1) the method of changing the host corresponding site speed
Noise load for SKF bearings are not very sensitive, but speed was very sensitive in cases where conditions allow, with methods of decreasing speed and increasing torque to achieve the same purpose, but it decreases the noise.
To reduce the noise of the pump system, previously used in motor speed under 1430r/min flow 10L/min pump, read speed for 710r/min motor and equipped with more specifications of the pump and get the same flow, pump itself, the noise of the pump bearings and oil pump motor bearings are significantly reduced, but the whole body of the expansion of space, costs have also increased.
(2) the use of chemical additives
NSK bearings, add some chemical additives in the lubricant, can reduce the bearing noise, such as a plant in Tianjin to produce a type of noise-reducing additives, low noise grease, bearings can be reduced on the basis of the noise from the original 3.9~9. 2dB, suitable for use in miniature and small bearings.
(3) using vibration absorbers or vibration
Using vibration absorbers or reduction in bearing noise or vibration isolation bearing noise, you get good results, but often pay a very high price in economic, sometimes make the body larger, thermal conditions worsen or easily rusting, use to date a comprehensive consideration, only after other measures taken are still unable to meet low-noise indicators after using this method.
The simplest example is the high speed instead of the thrust bearing and radial ball bearings withstand thrust, anti-rust lubricants in its circle over to full plastic jackets, thrust bearings with thrust bearings with cover or General in case of allowed, hole or outer circle in set with the same plastic sleeve, but control is not available when rotating with neighbouring mechanical friction or interference. This approach has a certain noise effects.
Another example is the join between the bearing and block bore a middle set, you can turn the system into the housings on the vibration attenuation, but this requires leveling it properly, otherwise there might be a reverse effect.
Yet another example is the use of sound-absorbing noise bearing system of acoustic enclosure completely closed or closed as much as possible. The internal noise reduction cover as glass fiber or polyurethane foam, inner surface is 0. 6-LMM thickness of steel plate, φ 1.2-1.5mm small holes on the surface, within a total area of about the whole surface of the hole 25%~30%, the outer surface is 2mm thickness steel plate.
Fiberglass or foam used to eliminate high frequency noise here, with a small hole in the surface to eliminate low frequency noise, but the surface of the plate are used to isolate the noise of rumor.



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