Mechanical noise generation and control

Update:26 Jan 2019
Summary:

  The friction, impact, unbalance and structural resona […]

  The friction, impact, unbalance and structural resonance of the motor running part will produce mechanical noise. The mechanical noise of the aluminum shell motor is relatively large, usually about 10%-15%. The mechanical noise includes bearing noise and the rotor imbalance. Noise and noise caused by assembly eccentricity. The noise value generated by bearing noise has a great relationship with the ball, the dimensional accuracy of the inner and outer ring grooves, the surface roughness and the shape tolerance. The following methods can be used to reduce the bearing noise:

1 When assembling, there should be a strict demagnetization cleaning process to wash off oil and iron filings;

2 Sealed bearings are used to prevent debris from entering; the fit between the outer ring of the bearing and the bearing chamber and the fit between the inner ring and the shaft should not be too tight;

3 In order to eliminate the axial clearance of the rotor, it is necessary to apply appropriate pressure to the bearing; reasonably configure the sealed elastic washer, and appropriately add lubricant to reduce friction;

4 For motors with special noise requirements, low-noise bearings should be used; when the load is not too large, oil-impregnated sliding bearings can be used, which can sometimes be 10 dB lower than the noise of the same size rolling bearings.

In addition, the dynamic balance of the rotor and fan is also an important means to reduce mechanical noise.