According to incomplete statistics, the highest failure rate of abnormal vibration of fan is 58.6% Due to the vibration, the operation of the fan will be unbalanced, and improper adjustment of the bearing sleeve will lead to abnormal temperature rise and vibration of the bearing.
Too small internal clearance of the bearing or poor design and manufacturing accuracy of the parts are the main reasons for the high operating temperature of the fan bearing. In order to facilitate the installation, disassembly, repair and maintenance of the fan equipment, bearing pedestal bearings with tight sleeve bearing cone bore inner ring are generally used in the design. However, problems are also likely to occur due to negligence in the installation procedure, especially the adjustment of the appropriate clearance. The internal clearance of the bearing is too small The operating temperature rises rapidly: the taper hole of the inner ring of the bearing is too loose to fit the locking sleeve, and the bearing is easy to be burnt due to the looseness of the mating surface in a short time.
If fan impeller is replaced during equipment maintenance. Both sides of the impeller are fixed and matched with the bearing of the bearing seat with a set sleeve. The failure of high temperature rise and high vibration value of free end bearing occurs after re test, and the bearing pedestal is disassembled_ I Several covers, manual slow rotation fan, found that the bearing roller at a specific position of the shaft also rolls in the non load area, so it can be determined that the bearing running clearance changes too high and the installation clearance may be insufficient. According to the measurement, the internal clearance of the bearing is only 0.04mm, and the eccentricity of the bearing is 0.08mm; Due to the large span of left and right bearings, it is difficult to avoid shaft deflection or bearing installation angle error. Therefore, large fans use f 1f spherical surface for automatic centering adjustment
Roller bearing. However, when the internal clearance of the bearing is insufficient Due to the limitation of the movement space, the automatic centering function of the rolling element inside the bearing is affected, and the vibration value will increase instead. The internal clearance of the bearing decreases with the increase of the fit tightness, and it is impossible to form a lubricating curved film. When the running clearance of the bearing decreases to zero due to the temperature rise, if the heat generated by the bearing operation is still in the dissipated heat, the bearing temperature will climb rapidly. At this time, if the machine is not stopped in time, the bearing will eventually burn out. The tight fit between the inner ring of the bearing and the shaft is the reason for the abnormal high temperature of the bearing operation in the wooden example.
During treatment, remove the locking sleeve, readjust the fit tightness of the shaft and inner ring, and take 0.1 Ommo as the clearance after bearing replacement. After reinstallation, start the fan, and the bearing vibration value and operating temperature will return to normal.
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