Whether the installation of the bearing is correct or not has a direct impact on the life of the bearing and the precision of the main engine. If the installation is not proper, the bearing has not only the vibration, the noise, the accuracy and the temperature rise, but also the risk of being burnt out. Otherwise, the installation will not only guarantee accuracy, but also prolong the life. Therefore, after the bearing is installed, the inspection must be carried out.
The key inspection items are as follows:
1. inspection installation position
Miniature bearings after installation, the first test of moving parts and fixed parts are touching, lubricating oil can smoothly flow into the bearing sealing device, and axial fastening device installation is correct.
2. test radial clearance
The radial clearance should be inspected except for the needle bearing with pre - interference. Deep groove ball bearings can be tested by hand rotation to be smooth and flexible, no vibration, no swing to right and left. Cylindrical roller and roller bearings can be inserted into the feeler feeler inspection, and roller bearing rings between the feeler insertion depth should be greater than the length of the roller 1/2. When the bearing radial clearance cannot be measured with a feeler, can measure the bearing in the axial displacement, radial clearance reduction instead. Usually, if the inner ring of the bearing is a conical hole, the axial movement on the conical surface is about 15 times that of the radial clearance.
Radial needle roller bearings, some unqualified after the installation can be adjusted, such as angular contact ball bearings, tapered roller bearings; some are in accordance with the standard provisions of manufacture has been adjusted, after the installation of unqualified cannot adjust, such as deep groove ball bearings, self-aligning ball bearings, cylindrical roller bearings, spherical roller bearing etc.. If this kind of bearing is not qualified after installation, and the radial assembly clearance is too small, the selection of the bearing is improper, or the assembly part is not properly processed. At this time, it is necessary to unload the bearing, find out the cause, and then reinstall it after it is eliminated. Of course, the bearing clearance is too large.
3. inspection of the tightness of the bearing and shoulder of the needle roller
In general, tight fitting bearings must be tightened on the shoulder. Test methods: (1) lighting method. The lamp alignment bearing and shaft shoulder, see light leakage judgement. If no light leakage, installation is correct; if the light evenly along the axis around the shoulder, it indicates that the bearing and shaft shoulder not tight, pressure to close to the bearing; if there is some light, it indicates that the bearing installation tilt, available hammer, brass or percussion sleeve bearing inner ring, ANN is slowly. (2) test feeler. The thickness of the feeler shall be 0. 03mm begins. Test, test plug in several bearing inner ring end face and shoulder the entire circumference, if there is a gap and very uniform, it indicates that the bearing is not installed in place to close the pressure bearing inner ring shaft; if the increase pressure on tight, that shaft corner fillet is too large, the bearing stuck, should be trimmed to the crankpin fillet, make it smaller; if it is found that the bearing inner ring end face and shoulder feeler bearing individual parts can not at this time must be removed, repaired, re install.