Raceway noise is a kind of stable and continuous noise excited by the rolling body rolling in the raceway when the bearing rotates. People pay attention to it only when its sound pressure Bearing Raceway level or tone is very large. In fact, the sound energy excited by the raceway sound is limited.
For example, under normal conditions, the high-quality 6203 bearing raceway sound is 25 ~ 27db. This kind of noise is typical of single row deep groove Bearing Raceway ball bearings bearing radial load. It has the following characteristics: A. noise and vibration are random; b. The vibration frequency is above 1kHz; c.
No matter how the rotating speed changes, the dominant frequency of noise is almost unchanged, and the sound pressure level increases with the increase of rotating speed; d. Bearing Raceway When the radial clearance increases, the sound pressure level increases sharply; e.
When the rigidity of bearing pedestal increases, the lower the total sound pressure level is, even if the speed increases, the total sound pressure level does not increase much; f. The higher the viscosity of lubricant, the Bearing Raceway lower the sound pressure level, but for grease lubrication, its viscosity and the shape and size of soap fiber can affect the noise value.
Coaxiality of the inner hole of the main bearing: the coaxiality error of the inner hole of the main bearing is mainly caused by the coaxiality error of the bearing hole, and the coaxiality error of the bearing hole is caused by the deformation of the cylinder block. When the radial circular runout of the main journal is within the specified tolerance, check the bite marks of the main journal and the bearing.
If the bite marks of each main bearing are obviously inconsistent, it indicates that the coaxiality error is large, which can be solved by scraping, boring the bearing or replacing the cylinder Bearing Raceway block, otherwise it is difficult to ensure the normal operation of the engine.
The elastic contact between the ferrule and the rolling body constitutes a nonlinear vibration system. When the lubrication or Bearing Raceway machining accuracy is not high, the natural vibration related to this elastic feature will be excited, and it will become noise when transmitted to the air.
As we all know, even if the contemporary superb manufacturing technology is used to process bearing parts, there will always be small geometric errors in varying degrees on the working surface, resulting in small fluctuations between the Bearing Raceway raceway and the rolling body and exciting the natural vibration of the vibration system.
Although the raceway noise of NSK bearing is inevitable, high-precision machining of the working surface of parts, correct selection of bearings and accurate use of bearings can be adopted to reduce noise and vibration.
Fit tightness of bearing and bearing hole: the fit tightness is guaranteed by the free spring opening of bearing and the height of surplus surface. Under the method of measuring the height of the remaining surface:
assemble the bearing according to the regulations, tighten the bolts of the bearing cover to the specified torque, loosen one of the bolts, and measure the clearance at the interface of the bearing cover with a feeler gauge, which shall be within the range of 0.05 ~ 0.15mm.
Bearing inner diameter: before measurement, the bearing shall be installed according to the regulations and the bearing cover bolts shall be tightened according to the specified torque. The inner diameter gauge Bearing Raceway shall be used to measure after the reference dimension is measured with the outer diameter micrometer.
The thinning area shall be avoided during measurement. The difference between the bearing inner diameter and the corresponding journal outer diameter is the fit clearance.