The speed reducer used in Roots fan is generally composed of a pair of cylindrical spur or helical gears with different diameters. Reducer in operation, such as the production of a lot of noise or a sudden increase in the sound, sometimes irregular banging sound, gear box body vibration, bearing temperature increases, premature wear of gears and other phenomena, there may be the following reasons.

1. The center of the gear shaft is installed incorrectly, the reducer large gear shaft and blower shaft, reducer pinion and motor shaft are not concentric, or the two gears are installed in a non-parallel, will cause vibration of the reducer. If the deviation from the concentricity is large, it will make the gear operation unstable and produce violent vibration, and, it will make the tooth surface suffer serious wear. If the two gears are not parallel, gear operation, it will produce local “crappy” parts, and when serious, the teeth will break. When the above phenomenon is found, the parallelism of the two gears and the contact surface of the inspection, and should be carried out to level the coupling and find the right.
2. There is incorrect clearance in various parts of the gear, which includes bearing clearance, side clearance where the two gears mesh, and inter-top clearance. These clearances must be adjusted to the required range. The correct clearance adjustment will make the gear in the operation of smooth, no noise; if the clearance is too large, it will occur gear shaking, banging, especially at the start, this phenomenon is particularly obvious; clearance is too small will make the operation of the sound noise, bearing temperature is high, the operation is not stable.
3. Poor lubrication is also one of the reasons for premature gear wear. The amount of lubricant is too low, the gear can not throw on the oil, will wear the tooth surface, noise; Conversely, the amount of lubricant is too much, will make the bearing temperature increase. If the impurities in the lubricating oil, especially hard substances such as iron filings, etc., will occur research bad teeth or make the gear broken and other phenomena. Therefore, the lubricating oil should be kept clean and changed regularly.
4. Poor casting or forging quality of the tooth shaft, improper heat treatment, rough machining quality, and insufficient stability of the blower in operation can reduce gear strength or cause premature gear wear.