Machining measures for reducing motor bearing noise

With the continuous improvement of people's living standards, the noise control of motors has become an indispensable and important technology, especially for motors operating in residential environments.

1. Solve the mechanical imbalance of the rotor to effectively control the noise. The unbalance of the rotor should be minimized, otherwise the balance accuracy will be low. The balance accuracy is related to the specifications, properties and service conditions of the motor. The greater the ratio of the diameter to the length of the rotor core, the greater the centrifugal force, and the higher the balance accuracy. The higher the rotor speed is, the higher the balance accuracy is required. The basic condition of the motor in use, such as poor rigidity of bearings and supporting parts, requires high balancing accuracy.

2. The bearing noise reduction method can be mainly started from the following aspects

(1) Pay attention to the selection of bearings. During the operation of most motor bearings, the vibration degree of the bearing will increase with the increase of the inner diameter of the bearing. The vibration will increase by 1~2dB for every 5mm diameter increase.

(2) Pay attention to the size of the bearing radial clearance. Too large radial clearance will cause low frequency noise to increase, on the contrary, too small clearance will cause high frequency noise to increase. In order to reduce the vibration and noise when the bearing rotates, the radial working clearance of the bearing shall be controlled within 1~9 μ M interval

(3) Pressurize the bearing moderately. The purpose is to eliminate the axial clearance of the rotor. Generally, wave spring washer or three-point elastic washer can be selected and placed at the shaft extension end.

(4) For motors with high noise requirements, silent bearings should be selected. When the load is small, oil-bearing sliding bearing can be selected, and its noise is generally about 10dB less than that of rolling bearings of the same size.