How to check whether the cylindrical roller bearing is invalid?

In order to keep the proper performance of cylindrical roller bearings under good conditions and use them for a long time, it is necessary to inspect and maintain cylindrical roller bearings, which is very important to prevent failures. During operation, the rolling sound, vibration, temperature and lubricant of cylindrical roller bearings should be mainly checked.

When the performance index of cylindrical roller bearing is lower than the use requirement and cannot work normally, cylindrical roller bearing will fail or even fail. Once the cylindrical roller bearing fails and other unexpected situations occur, the machinery and equipment will stop running and lose their functions. Therefore, it is necessary to find out the reasons in a short time and take corresponding measures.

Rolling sound of cylindrical roller bearings.

One kind of noise of cylindrical roller bearing is produced by cylindrical roller bearing itself, that is, the inherent noise of cylindrical roller bearing; The other is the noise generated after the installation of cylindrical roller bearings, which has nothing to do with the noise of cylindrical roller bearings themselves. Some problems can be analyzed by listening to the sound.

A) Noise related to the manufacture of cylindrical roller bearings: including cage noise and vibration. Cage noise mainly occurs in spherical cylindrical roller bearings and tapered roller bearings. When the cylindrical roller bearing rotates, the vibration of the cage and the collision between the cage and the roller will make a sound, which is periodic. Tremolo is a kind of sound with a certain frequency, which is caused by the large waviness of raceway surface.

B) Inherent noise: raceway sound: raceway sound is generated by the elastic characteristics of the roller when it contacts the raceway. When the cylindrical roller bearing rotates, the roller rolls on the raceway and makes a continuous and smooth sound; Abnormal rolling friction sound can make uncomfortable abnormal metal friction sound such as "squeak, squeak", but it will not make such sound when it is well lubricated. Therefore, it is not a problem under normal circumstances, and you need to pay attention after the noise increases.

C) Noise caused by improper use: all kinds of cylindrical roller bearings are available. When the raceway surface or roller surface of cylindrical roller bearing is scratched, pitted and rusted, it will produce noise and vibration for a certain period. When dust invades the running cylindrical roller bearing, it will produce dirt noise, which is aperiodic and accompanied by vibration, and its sound level is not fixed, sometimes it is not.

2. Vibration of cylindrical roller bearing

The vibration of cylindrical roller bearing has obvious influence on the failure of cylindrical roller bearing. For example, peeling, indentation, corrosion, cracks, wear and so on. Will be reflected in the vibration detection of cylindrical roller bearings, so the vibration can be measured by a special vibrometer for cylindrical roller bearings, and the specific situation of abnormal vibration can be inferred from the frequency distribution. Because the use conditions of cylindrical roller bearings or the installation position of sensors are different, the measured values are different, so it is necessary to analyze and compare the measured values of each machine in advance to determine the judgment standard.

3. Temperature of cylindrical roller bearing

Usually, the temperature of cylindrical roller bearings rises slowly with the start of operation, and reaches a stable state after 1 ~ 2 hours. The normal temperature of cylindrical roller bearings varies with the heat capacity, heat dissipation, speed and load of the machine. If lubrication and installation are improper, the temperature of cylindrical roller bearings will rise sharply, resulting in abnormal high temperature. At this point, the machine must be stopped and necessary preventive measures must be taken.

4. Lubricants

Lubrication has an important influence on friction and wear, temperature rise and vibration of rolling cylindrical roller bearings. Without normal lubrication, cylindrical roller bearings cannot work. The analysis of the damage causes of cylindrical roller bearings shows that about 40% of the damage of cylindrical roller bearings is related to poor lubrication, so good lubrication of cylindrical roller bearings is an effective measure to reduce the friction and wear of cylindrical roller bearings. In addition, the lubrication of cylindrical roller bearings also plays the role of heat dissipation, rust prevention, sealing and impact reduction. It must be ensured that the lubricant will not expire and the selection should be correct.