HF1816 needle roller bearings

The two sides of the impeller are fixedly matched with the bearing seat using adapter sleeves. After re-testing, the free-end bearing had a high temperature and high vibration value. I disassembled the upper cover of the bearing turns and manually rotated the fan at a slow speed. It was found that the bearing roller at a specific position of the rotating shaft also rolled in the non-load area. This confirms that the needle roller bearing running clearance changes on the high side and the installation clearance may be insufficient. After measurement, it was found that the internal clearance of Timken bearings is only 0.04mm, and the eccentricity of the rotating uranium reaches 0.08mm. Due to the large span of the left and right bearings, it is difficult to avoid deflection of the rotating shaft or errors in the bearing installation angle. Therefore, large fans adopt automatic alignment Center-adjusted spherical roller bearings. However, when the internal clearance of the bearing is insufficient, the rolling parts inside the bearing are limited by the movement space, and their self-centering function is affected, and the vibration value will increase instead. The internal clearance of the bearing decreases as the fit tightness increases, and a lubricating film cannot be formed. When the bearing operating clearance drops to zero due to temperature rise, if the heat generated by the bearing operation is still greater than the heat dissipated, the bearing temperature is It will climb rapidly. At this time, if the machine is not stopped immediately, the bearing will eventually burn out. The tight fit between the inner ring of the bearing and the shaft is the reason why the bearing runs at an abnormally high temperature in this case.