What are the three allowable items of bearing during installation and disassembly? Analysis of inspection items after bearing operation

After the bearing is installed, in order to check whether the installation is correct, an operation inspection shall be carried out. Small machines can be rotated by hand to confirm whether they rotate smoothly. The inspection items include poor operation caused by foreign matters, scars and indentation, unstable torque caused by poor installation and poor processing of mounting base, excessive torque caused by too small clearance, installation error and sealing friction, etc. If there is no abnormality, power operation can be started.
Large machinery cannot be rotated manually, so the power shall be cut off immediately after no-load start, and the machinery idles. Check whether there is vibration, noise, contact of rotating parts, etc. after confirming that there is no abnormality, enter the power operation. Power operation, starting from no-load low speed, slowly increase to the rated operation under the specified conditions. During the test run, the inspection items are whether there is abnormal sound, bearing temperature change, lubricant leakage or discoloration, etc. If any abnormality is found, stop the operation immediately, check the machinery, and remove the bearing for inspection if necessary.
The bearing temperature can generally be inferred from the external temperature of the bearing seat. However, it is more accurate to directly measure the temperature of the bearing outer ring by using the oil hole. The bearing temperature rises gradually from the beginning of operation, and the temperature is usually stable after 1 ~ 2 hours. If the bearing is not installed properly, the temperature will rise sharply, resulting in abnormal high temperature. The reasons are too much lubricant, too small bearing clearance, poor installation, excessive friction of sealing device, etc. In the case of high-speed rotation, the wrong selection of bearing structure and lubrication mode is also the reason. The rotating sound of the bearing is checked with a stethoscope, and there are strong metal noise, abnormal sound, irregular sound and other abnormalities. The reasons include poor lubrication, poor accuracy of shaft or bearing seat, bearing damage, foreign matter intrusion, etc.