A sound detector is used to check the size and sound quality of the rolling sound of the running bearing. Even if the bearing has slight peeling and other damage, it will emit abnormal sound and irregular sound, which can be distinguished by the sound detector.

The use of hearing to identify irregular movements is a very common method. For example, using an electronic stethoscope to detect abnormal noise of a part is often the method used by experienced operators.
If the bearing is in a good continuous rotation state, it will emit a low whine sound. Sharp hissing, squeaking and other irregular sounds often indicate that the bearing is in poor continuous rotation.

High-pitched creaking noises can be caused by improper lubrication. Improper bearing clearance can also cause metallic noise. Indentations in the concave track on the bearing outer raceway can cause vibration and cause a smooth, crisp sound. If it is caused by knocking scars during installation, noise will also be generated, and the noise will vary with the speed of the bearing speed.

Intermittent noise may indicate damage to the rolling elements. This sound occurs when the damaged surface is rolled over, and contamination in the bearing often causes a hissing sound. Severe bearing damage will produce irregular and loud noises.

a. The cleaning of the bearing is divided into rough cleaning and fine cleaning, and the bearing can be placed on a metal mesh frame at the bottom of the container used.
b. During rough cleaning, use a brush in the oil to remove grease or adhesions. At this time, if the bearing is rotated in oil, be careful that the rolling surface may be damaged by foreign matter or the like.
c. During fine cleaning, slowly rotate the bearing in the oil, which must be done carefully.

The commonly used cleaning agent is neutral non-water diesel oil or kerosene, and sometimes warm lye is also used as needed. Whatever cleaning agent is used, it should be filtered frequently to keep it clean.
After cleaning, apply anti-rust oil or anti-rust grease to the bearing immediately.

2. Inspection and judgment:
In order to judge whether the removed bearing can be reused, the bearing should focus on checking its dimensional accuracy, rotation accuracy, internal clearance, as well as the mating surface, raceway surface, cage and sealing ring.

The inspection results can be judged by those who use inertia bearings or those who are proficient in bearings.

The criteria for judging bearings vary according to mechanical properties and importance, inspection cycles, etc. In case of the following damage, the bearing shall not be reused and must be replaced.
a. Fractures and defects of bearing parts.
b. Peeling of the rolling surface of the raceway surface.