NTN bearings in the rolling bearing inspection items have sound, vibration, temperature, lubrication status, etc., as follows:
1 bearing rolling sound Use the sound of the size and sound quality of the audio equipment to check the operation of the rolling bearing, even if the bearing is slightly peeled off and other damage, the abnormal tone and the sound emitted by the irregular measuring device will be distinguished from the sound measurement.
2 bearing vibration bearing vibration is very sensitive to bearing damage, such as spalling, indentation, rust, crack, wear, etc. will be reflected in the bearing vibration measurement, therefore, by using special bearing vibration measurement (frequency analyzer, etc.), measuring vibration Size, frequency analysis, can be inferred through unusual situations. The measured values ​​of the position where the sensor is used or mounted under bearing conditions are different, so each machine requires analysis and comparison of previously determined standard measured values.
3 bearing temperature The temperature of the bearing, generally the temperature outside the bearing room, can be inferred, if the hole can be used to directly measure the bearing outer ring temperature, it is more appropriate. Normally, the bearing temperature rises for 1-2 hours and slowly reaches a steady state. The heat capacity of the bearing is normal for the machine, the heat capacity is large, the speed and load are varied. If the NTN bearing is operated for inspection and troubleshooting, and the appropriate part is installed, the temperature rise of the bearing will be abrupt, and the operation will stop when abnormally high temperature occurs, taking necessary precautions.
After the demolition, the NTN bearing damage is checked, and the damaged bearing is used to determine the cause of the bearing failure and damage.
1. Metal foil on the raceway surface Under the cyclic pulse load function, the roller bearing and the outer ring raceway surface cause periodic changes in contact stress. When the stress cycle reaches a certain value, or when rolling, the outer ring raceway working surface is fatigued and peeled off. If the bearing load is too large, this fatigue is worse. In addition, the bearings are not installed correctly, the shaft is bent, and there is also a raceway peeling off. Runway fatigue spalling operations reduce the accuracy of the shaft and cause vibration and noise in the body.
2. Bearing Burns The Burns bearing's raceway, rolling temper color. The reason is usually insufficient lubrication of the burn, the quality of the oil does not meet the requirements or deterioration, and the bearing assembly is too tight.
3. Plastic deformation The crater of the contact surface of the bearing raceway and the roller is uneven, indicating the plastic deformation of the bearing. The reason is a large static load-bearing or impact load, and the yielding local stress of the working surface material exceeds the limit, which generally occurs in bearings that rotate at low speeds.
4. Bearing ring cracking The bearing ring crack may be due to tight, loose bearing outer ring or inner ring bearing, bearing tolerance deformation, mounting bearing and surface finish.
5. Cage debris The reason is insufficient lubrication, ball crushing, seat skew and so on.
6. Stick to the rolling iron cage The reason is that the human body may stay in the rolling cage or insufficient lubrication.
7. The seat race is seriously worn. The seat may fall into foreign countries, and the oil or lubricant grade is less appropriate.
NTN bearing damage, the main factors are: under load conditions, lubrication, assembly conditions, environmental conditions and materials or manufacturing accuracy