Analysis and maintenance of abnormal noise in motor bearings

1、The motor bearing retainer emits a strange sound of "sigh, sigh, sigh..."

Cause analysis:

It can be generated by the vibration and collision between the retainer and the rolling element, regardless of the type of lubricating grease, and is more likely to occur when subjected to torque, load, or large radial clearance.

Solution:

A. Improve the precision of the retainer;

B. Select bearings with small clearance or apply preload to the bearings;

C. Reduce torque load and installation errors;

D. Choose good fats and oils.

2、The motor bearings emit a continuous buzzing sound "buzzing..."

Cause analysis:

The no-load operation of the motor produces a sound similar to a buzzing sound, and the motor experiences abnormal axial vibration, with a buzzing sound when turned on or off.

Specific features:

The lubrication condition is not good, and in winter, motors with ball bearings at both ends are prone to unstable vibration caused by axial vibration when the shaft alignment performance is poor.

Solution:

A. Use grease with good lubrication performance;

B. Add preload to reduce installation errors;

C. Select bearings with small radial clearance;

D. Improve the rigidity of the motor bearing seat;

E. Strengthen the centering of bearings.

Note: Point 5 has a fundamental improvement effect, using 02 small groove curvature and 01 large groove curvature.

3、Paint rust on motor bearings

Cause analysis:

Due to the drying of the motor bearing casing paint oil, the volatile chemical components corrode the end face, outer groove, and groove of the bearing, causing abnormal noise in the groove after corrosion.

Specific features:

After corrosion, the surface of the bearing rusts more severely than the first surface.

Solution:

A. Assemble the rotor, casing, and air dry or dry them;

B. Reduce motor temperature;

C. Select the appropriate paint model;

D. Improve the ambient temperature for placing motor bearings;

E. Using suitable fats and oils, grease causes less rusting, while silicone oil and mineral oil are the most likely to cause it;

F. Adopting vacuum impregnation paint process.

4、The motor bearings emit impurity sounds

Cause analysis:

An irregular abnormal sound is emitted due to the cleanliness of bearings or grease.

Specific features:

The sound is occasional and irregular, with varying amplitudes and amplitudes, and is more frequent on high-speed motors.

Solution:

A. Choose good fats and oils;

B. Improve the cleanliness before grease injection;

C. Strengthen the sealing performance of bearings;

D. Improve the cleanliness of the installation environment.

5、The motor bearings emit high-frequency, vibrating sounds such as "da da..."

Specific features:

The frequency of sound varies with the speed of the bearing, and the surface waviness of the parts is the main cause of noise.

Solution:

A. Improve the surface machining quality of bearing raceways and reduce the amplitude of corrugation;

B. Reduce collisions and injuries;

C. Correct the clearance preload and fit, check the operation of the free end bearing, and improve the accuracy installation method of the shaft and bearing seat.

6、Motor bearings overheat due to temperature rise

Specific features:

After the bearing is running, the temperature exceeds the required range.

Cause analysis:

A. Excessive lubricating grease increases the resistance of the lubricant;

B. Excessive internal load caused by small clearance;

C. Installation error;

D. Friction of sealing equipment;

E. Crawling of bearings.

Solution:

A. Choose the correct oil and use it in an appropriate amount;

B. Correct the clearance preload and fit, and check the running condition of the free end bearing;

C. Improve the accuracy and installation method of bearing seats;

D. Improve the sealing form.

7、Poor hand feel of motor bearings

Specific features:

When holding the bearing and rotating the rotor, feel impurities and blockages inside the bearing.

Cause analysis:

A. Excessive clearance;

B. Improper fit between inner diameter and shaft;

C. Canal damage.

Solution:

A. Keep the clearance as small as possible;

B. Selection of tolerance zones;

C. Improve accuracy and reduce damage to channels;

D. Oil selection.