According to the bearing knowledge, the clearance of the bearing affects the noise of the motor bearing. The clearance of the bearing has a great influence on the operation of the bearing. The clearance of the bearing is also called the internal clearance of the bearing. It refers to the moving distance of the other ring relative to the fixed ring when one ring of the bearing is fixed. The radial movement distance of this movement is called the radial clearance, and the axial movement distance is called the axial clearance. The clearance of the most commonly used deep groove ball bearings, cylindrical roller bearings, etc. in industrial motors generally refers to radial clearance, while angular contact ball bearings refer to axial clearance.
Due to the influence of working conditions, the clearance of the motor bearing during normal operation is different from the factory clearance. Among them, the motor bearing is affected by the tolerance of the front and rear of the installation, which will produce a change in the clearance. Generally, the fit between the inner ring and the shaft of the horizontal internal rotation motor bearing is tighter than that of the outer ring of the bearing and the bearing chamber, and the inner ring of the bearing will expand outward, so that the clearance of the bearing is reduced. On the other hand, the motor generates heat during operation, which also affects the clearance of the bearing. Usually, the inner ring temperature of the bearing is 5°~15° higher than the outer ring temperature of the bearing. This temperature difference causes the thermal expansion of the inner and outer rings of the bearing to be different, and the inner ring expands to increase, which reduces the clearance of the bearing. Thus, the working clearance of the bearing has the following relationship with the initial clearance of the bearing. C work = C initial - ΔT-ΔF (1) where: C work --- work clearance; C initial --- initial clearance; ΔT --- clearance reduction due to temperature changes; ΔF― -- The amount of clearance reduction due to tolerance fit.