Motor bearing noise reduction

The use of high-quality bearings, selected bearing models and sizes, appropriate bearing component design, improve the manufacturing precision of the components with the bearing, reasonable selection of the matching level, as well as a clean installation environment, civilized installation process, etc., to reduce the motor Both vibration and noise have significant effects. At present, in large motors or fractional horsepower and the following micromotors, sliding bearings are generally used, especially micromotors, most of which require low noise, and high precision rolling bearings are too expensive. The powder metallurgy oil-impregnated bearings developed in recent years can ensure that the bearing noise is no more than 40dB, even reaching 30dB.


For rolling bearings, the following measures can be taken to reduce its noise:

  1. The use of a spring ring (such as a corrugated spring) to apply axial pre-stress to the bearing can reduce the vibration caused by the unconstrained movement of the rolling element. However, the corrugated spring must have sufficient thrust to track the excitation of the axial vibration, not too hard, the force acting on the outer ring of the bearing should be relatively uniform, etc., otherwise it may have the opposite effect or no effect. The optimum value of the axial preload can be determined experimentally. Experimental data shows that when the axial preload is 196-490 N, the vibration speed is low.

  2.  Add an elastic damper to the support device. Typically, this helps to reduce vibration and noise at frequencies above a few hundred Hz.

  3.  Use bearings with retainers made of synthetic plastic or sturdy mechanical retainers that are quieter at high speeds.

  4. Use bearings with shrouds or gaskets to prevent dirt or foreign objects from entering the bearings.

  5.  The natural frequency of the bearing outer ring should be detuned from the natural frequency of the support member.

  6.  Choose the right working clearance. From the noise point of view, the working clearance is less important than the bearing's waviness, roughness, motor machining accuracy, fit tolerances and installation process, but it should have a relative optimum range.

Reprinted from the network