1. Poor lubrication (accounting for about 50%)

     According to the survey, poor lubrication is one of the main reasons for the premature damage of imported bearings. The main reasons include: improper selection of lubricant or lubricating oil, not filling lubricant or lubricating oil in time; not filling lubricant or lubricating oil in place; and so on.

Suggestion: Choose the correct lubricant or lubricating oil, use the correct lubrication and filling method, and maintain the bearing regularly.

     2. Improper installation (about 16%)

1. Use brute force during installation. Hitting the imported bearing directly with a hammer will cause the most damage to the bearing; it is the main cause of deformation.

2. The installation is not in place, the installation is deviated or not installed in the bearing position, resulting in too small bearing clearance. The inner and outer rings are not at the same rotation center, resulting in non-concentricity.

     Suggestion: choose appropriate or professional bearing installation tools, and use special instruments to detect after installation.

     3. Fatigue (about 34%)

      Common causes of fatigue damage may be: long-term overloading of bearings; failure to maintain in time, or improper maintenance; equipment aging, etc.

     4. Pollution (about 14%)

Pollution will also lead to premature damage to imported bearings. Pollution refers to the entry of dust, metal filings, etc. into the bearing. The main reasons include: opening the bearing package prematurely before use, causing pollution; the working environment is not clean during installation, causing pollution; impurities enter the NTN bearing and cannot work normally.

    The length of service life of the bearing is generally affected by the two factors of material and process.

    The material of the bearing determines the service life of the bearing to a large extent. The metallurgical quality of the bearing used to be the main reason for the early failure of the rolling bearing. The impact of bearing material on service life has been greatly improved in metallurgical technology, and after the emergence of bearing steel and other materials, it has been greatly improved.

    In the failure analysis of bearings, the proportion of bearing failures caused by raw materials has dropped significantly, but materials are still an important cause of bearing failures, and are the main constraints on bearing service life.

The manufacturing process of bearings is complicated, and the finished product can only be obtained after many processes. Among them, the technical capabilities and completion quality of forging, heat treatment, turning and grinding processes will affect the service life and application effect of bearings, especially heat treatment and The grinding process is the direct cause of many bearing failures and needs to be highly valued by manufacturers.

    After the bearing is installed, in order to check whether the installation is correct, it is necessary to carry out a running inspection. Small machinery can be rotated by hand to determine whether the rotation is smooth. The inspection items include poor operation caused by foreign objects, scars, and indentations, unstable torque due to poor installation and poor processing of the mounting seat, excessive torque caused by too small clearance, installation errors, and seal friction, etc. wait. If there is no abnormality, the power operation can be started.

    Large machines cannot be rotated by hand, so cut off the power immediately after starting without load, run the machine idly, check whether there is vibration, noise, whether there is contact with the rotating parts, etc. After confirming that there is no abnormality, enter the power operation.

Power operation starts from no-load and low speed, and gradually increases to the rated operation of the predetermined premise. The inspection items during the test run are whether there is abnormal sound, temperature change of NTN bearing, leakage or discoloration of lubricant, etc. If an abnormality is found, stop the operation immediately, check the machine, and remove the bearing for inspection if necessary.

    The bearing temperature can usually be inferred from the external temperature of the bearing seat. However, it is more accurate to directly measure the temperature of the outer ring of the bearing by using the oil hole. The bearing temperature gradually rises from the start of operation, and usually stabilizes after 1 to 2 hours. If the bearing is installed poorly, the temperature will rise sharply, resulting in abnormally high temperature. The reasons are, for example, too much lubricant, too small bearing clearance, poor installation, excessive friction of the sealing device, etc. In the case of high-speed rotation, the wrong choice of bearing structure and lubrication method is also the reason.

    The rotation sound of bearings is checked with a stethoscope, etc., and there are strong metal noises, abnormal sounds, and irregular sounds, which indicate abnormalities. The reasons are poor lubrication, poor precision of the shaft or bearing seat, bearing damage, foreign matter ingress, etc.