Selection principles of fan bearings

I suggest you first look for the cause in terms of bearing assembly and lubrication. Generally speaking, there are very few errors in the original design. Is there a lot of vibration during operation? If there is vibration, please check whether there is scale on the impeller? Have you ensured that there is enough clearance between the bearing glands at both ends of the bearing box and the bearing outer ring to ensure the amount of axial movement of thermal expansion? If there is no problem, then check whether the bearing quality is not up to standard. Attachment: The assembly method and precautions for rolling bearings are as follows. (1) Bearings that are originally hot-sleeved must still use hot-sleeve fit during assembly. Do not change the cold-sleeve fit. Otherwise, the bearing will produce noise and heat during operation and shorten its service life. (2) Before assembling the rolling bearing, check the matching tolerance of the bearing inner ring and the journal inner ring as well as the matching tolerance of the bearing outer ring and the end cover bearing seat. At the same time, check the smoothness of the mating surfaces of the bearing, journal, and end cover bearing seat. (3) The fit between the inner ring of the bearing and the journal is a base hole system, and the fit between the outer ring of the bearing and the bearing chamber of the end cover is a base shaft system. Therefore, when the fit size does not meet the requirements, the dimensions of the journal and the end cover bearing seat can only be corrected. (4) When assembling rolling bearings, first grease the inner bearing cap and insert it into the shaft, and then assemble the bearing. Apply a thin layer of engine oil to the journal and start assembling the bearing. (5) When copper rods are used to drive bearings, due to uneven stress on the inner ring of the bearing, the assembly quality is not high. According to statistics, 35% of bearing failures (you ask me) are caused by improper maintenance operations. Therefore, in principle, this method is not allowed. (6) Use the method of driving the sleeve into the bearing to ensure that the bearing is stressed evenly. The sleeve can be made of soft metal or copper tube, its inner diameter should be 2~3mm larger than the journal, and its thickness should be smaller than the thickness of the bearing inner ring. The contact between the sleeve and the end face of the inner ring of the bearing should be tight. The sleeve is required to be wiped clean in advance to remove burrs and dirt. Otherwise, dirt and burrs will fall into the bearing when the sleeve is struck. (7) Before hot-sleeving, you must first carefully check the matching dimensions of the bearing and journal. Because hot-sleeving is different from cold-sleeving, it is not easy to detect whether the fit tolerance and interference degree of the journal are appropriate during the hot-sleeving process. In the cold-sleeving process, you can indirectly judge whether the fit interference is appropriate based on the pressing force during the insertion process. (8) Heat the bearing to about 100°C before hot-sleeving. Unsealed bearings can be boiled in engine oil for about 5 minutes. When the inner ring swells, quickly insert the bearing onto the journal. After the bearing cools and shrinks, the inner ring of the bearing will be tightly fixed on the journal. For sealed bearings. Since the inside is filled with grease, do not use oil to heat it. You can use electric heating to evenly heat the bearing and insert it into the shaft. (9) When assembling the bearing, the side of the bearing with the model number should face outward to facilitate maintenance and replacement. (10) The bearing should be filled with grease. The grease should be squeezed in from one end of the bearing and squeezed out from the other end of the bearing so that the grease is filled in the bearing. The amount of oil applied to the inner cavity of the bearing cover should account for 1/3~2/3 of the total volume of the bearing cover. This post was last edited by lth on 2008-2-26 20:17 ]