Analysis and Solution to Electric Machine Bearing Abnormal Sound

1. Holder sounds "xili xili…":

Analysis of cause: generated by vibrating and dashing of the holder and rolling element. No matter which kind of grease it is, the sound can be produced. It is easily produced when the holder is subject to great moment and load or the radial windage is large.

Solutions:

A, enhance holder precision

B, choose bearing with small windage or exert preload on bearing

C, lower moment load, reduce alignment error

D, choose good grease

2, Continuous bumming "buzz…"

Analysis of cause: motor can produce sound like bumming when it operates without load, and axial abnormal vibration happens on the motor. There is buzz when starting up or shutting down.

Definite characteristics: easy to happen when lubricating condition is not good, and it is also easy to happen when the two ends use ball bearings in winter. When the shaft self-aligning capability is not good, an unstable vibration will be produced under the effect of axial vibration.

Solutions:

A, use grease with good lubricating property

B, add preload and reduce aligning error.

C, choose bearing with small radial windage

D, enhance the rigidity of motor bearing support

E, strengthen self-aligning capacity of bearings

Note: the fifth item functions as fundamental improvement, adopt 01 minor groove curvature and 01 large groove curvature.

3. Paint rust

Analysis of cause: after the paint on the electric machine bearing casing dries, chemical composition volatilizes from the paint erodes the end surface, the outer race and the raceway of the bearing, and makes the eroded raceway produce abnormal sound.

Definite characteristics: the eroded bearing surface rusts much severe.

Solutions:

A, assemble the rotor and casing after they are dried or parched.

B, lower motor temperature

C, choose model number of suitable paint

D, improve ambient temperature of places where electric machine bearing is positioned.

E, use adaptive oil, fatty oil causes little rust, while silicon oil and petrolatum are the easiest to cause rust.

F, adopt vacuum paint dipping technology.

4. Stray noise:

Analysis of cause: Caused by cleanliness of bearing or grease, a type of irregular abnormal sound is produced.

Definite characteristics: the sound is irregular, sometimes it appears, and sometimes it disappears; sometimes it is loud, and sometimes it is low. The sound usually appears on high-speed electric machine.

Solutions:

A, choose good grease

B, enhance the cleanliness before filling grease.

C, strengthen the sealability of bearings

D, enhance cleanliness of mounting environment.

5, High frequency vibration sound " clatter ..."

Definite characteristics: the sound frequency changes with bearing rotate speed. Waveness of the parts surface is the main cause to noise.

Solutions:

A, improve process quality of bearing raceway surface, lower waveness amplitude.

B, reduce contusion

C, modify windage preload and matching, check operation of free end bearing, and improve precision mounting method of shaft and bearing support.

6. Temperature rise:

Definite characteristics: after bearings operate, the temperature overcomes required range.

Analysis of cause:

A, too much grease make the resistance of lubricant increase.

B, too small windage causes too large inner load.

C, alignment error;

D, friction of sealing device

E, bearing crawl

Solutions:

A, choose correct grease proper dosage.

B, modify windage preload and matching, check the operating circumstance of free end bearings

C, improve the bearing support precision and mounting methods

D, improve sealing form.

7. Bearing hand touch is not good:

Definite characteristics: when holds bearing rotator by hand, a feel of impurity and block in the bearing is felt.

Analysis of cause:

A, too large windage

B, the matching of inner diameter and shaft is not proper.

C, raceway damage

Solutions:

A, the windage should be as small as possible

B, tolerance zone choice

C, enhance precision, reduce raceway damage

D, grease choice