How to check the operation force of imported bearings

After installing the imported bearings, in order to verify whether the installation is correct, a running inspection should be carried out. Small machinery can be rotated by hand to confirm whether the imported bearings rotate smoothly. The inspection items include poor operation caused by foreign objects, scratches, and indentations, unstable torque due to poor installation and processing of the mounting seat, excessive torque caused by small clearance, installation errors, and sealing friction, etc. If there are no abnormalities at this point, the imported bearings can be started to operate with power.

(1) The resultant force of the applied force should pass through the axis of the bearing as much as possible, which requires the application point to be uniform, symmetrical, and smooth, and applied through a sphere or parallel to the axis.

(2) The magnitude of the applied force should be smooth and uniform, without any impact. This requires the use of oil pressure or tools that can apply stable tension or pressure. If hammering is necessary, it should also be buffered by softer and less debris free metals such as copper sleeves, and the impact force should be as light and gentle as possible. It is recommended to use a copper rod or hammer for hammering.

(3) To avoid applying force through rolling elements, it is required to apply force through the inner ring (shaft ring) when installing and removing the inner ring, and apply force through the outer ring when installing and removing the outer ring.

(4) The drag force should continue to the appropriate level, for example, when installing the bearing, the force should be stopped when the bearing is just installed in the correct position, ensuring that the end face of the ring (washer) is against the seat hole or the shoulder end face of the shaft, neither too tight nor not installed in place.

Large machinery cannot be manually rotated, so the power is immediately cut off after starting with no load, and the machinery runs idle. Check for vibration, noise, and contact between rotating parts, and confirm that there are no abnormalities before entering power operation. Power operation starts from no-load low speed and gradually increases to the rated operation under the specified conditions. The inspection items during the trial operation include whether there are any abnormal sounds, changes in bearing temperature, leakage or discoloration of lubricants, etc. If any abnormalities are found, the operation should be immediately stopped, the machinery should be inspected, and if necessary, the bearings should be removed for inspection.

The temperature of imported bearings can generally be inferred based on the external temperature of the bearing seat. But using oil holes to directly measure the temperature of the outer ring of the bearing is more accurate. The temperature of the bearing gradually increases from the beginning of operation and usually stabilizes after 1-2 hours. If the bearing is not installed properly, the temperature will rise sharply, resulting in abnormal high temperatures. The reasons for this include excessive lubricant, small bearing clearance, poor installation, and excessive friction in the sealing device. In high-speed rotating situations, errors in the selection of the structure and lubrication method of the self-aligning ball bearing are also reasons.

The rotation sound of imported bearings was checked with a stethoscope, and strong metal noise, abnormal sound, irregular sound, etc. indicated abnormalities. The reasons for this include poor lubrication, poor accuracy of the shaft or bearing seat, damage to the self-aligning ball bearing, and intrusion of foreign objects.