A sound meter is used to check the size and sound quality of the rolling sound of the bearing in operation. Even if the bearing is slightly damaged such as peeling, it will emit abnormal and irregular sounds, which can be distinguished by the sound meter.

　　It is a very common method to use hearing to recognize irregular movements. For example, using an electronic stethoscope to detect abnormal noise of a certain part is often a method used by experienced operators.

　　 If the bearing is in a good continuous rotation state, it will make a low whine sound. If there is a sharp hiss, squeak and other irregular sounds, it often indicates that the bearing is in a poor continuous rotation condition.

　　 The sharp squeaking noise may be caused by improper lubrication. Inappropriate bearing clearance can also cause metallic noise. The dents of the concave track on the bearing outer ring track will cause vibration and cause a smooth and crisp sound. If it is caused by knocking scars during installation, noise will also be generated, and this noise will vary with the speed of the bearing.

If there is intermittent noise, it means that the rolling parts may be damaged. This sound occurs when the damaged surface is rolled over, if there are contaminants in the bearing, it will often cause a hissing sound. Severe co-carrying damage will produce irregular and loud noise.

　　A. For rough washing, use a brush to remove grease or adhesions in oil. If the bearing is rotated in oil at this time, be careful that the rolling surface may be damaged by foreign matter.

　　B. The cleaning of the bearing is divided into rough cleaning and fine cleaning. The bearing can be placed on the bottom of the container with a metal grid.

　　C. During fine washing, slowly rotate the bearing in oil and perform it carefully.

　　The cleaning agent usually used is neutral water-free diesel or kerosene, and sometimes warm lye etc. are used as needed. No matter what kind of cleaning agent is used, it must be filtered frequently to keep it clean.

　　 After cleaning, immediately apply anti-rust oil or anti-rust grease on the bearing.

　　 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, mating surface, raceway surface, cage, and sealing ring.

　　 Regarding the inspection results, it can be judged by those who use inertial bearings or those who are proficient in bearings.

　　Bearing judgment standards vary according to mechanical performance and importance, inspection cycle, etc. If the following damage occurs, the bearing must not be reused and must be replaced.

　　A, the peeling of the rolling surface of the raceway surface.

　　B. Fractures and defects of bearing parts.