What are the reasons for the high noise level of construction hoists?

　　As construction machinery, building hoists inevitably produce some noise. However, if the noise level is excessively high, it can significantly disturb nearby residents and even pose a serious nuisance and harm to the operators themselves—this is something that deserves our attention. So, what exactly are the main causes of the loud noise generated by building hoists?

　　I. Chassis

　　We believe that the design and manufacturing of the chassis may contribute to noise generation: The chassis adopts a box-shaped structure, and not all weld seams are continuous. Each weld seam on the chassis varies in length and height, and there are significant individual differences in terms of rigidity. If even slight vibrations occur, these vibrations will be amplified. The chassis is welded from steel plates and lacks any inherent shock-absorbing or noise-damping capabilities. Moreover, if its natural frequency closely matches the meshing frequency of the gears, some machines could experience substantial resonance triggered by minor gear vibrations, leading to an increase in noise levels.

　　II. Bearing Clearance

　　Some people believe that the noise, which accompanies the drum assembly and transmission components, may be caused by the clearance between the sliding bearings of the drum. We have carefully selected the fitting clearances for the drum components to ensure that the clearance between the bearing bore and the main shaft meets the requirements specified in the drawings. After assembly, we conduct tests. During these tests, we use a variable-frequency motor to adjust the speed and observe the impact of speed on the noise level.

　　III. Gear Quality

　　After inspecting the tolerances for the common normal length of the gears, the tolerance for variations in the common normal length, the radial runout of the gear ring, the coaxiality of the holes associated with the roller, and the runout of the spindle journal—all these parameters were found to be within the specified standard ranges. However, further inspection of the gears revealed that the tooth profile errors exceeded the allowable limits. The root cause was identified as improper sharpening of the hobbing cutter. Since this is a large-module tool, the material being cut requires reworking, resulting in significant cutting resistance during hobbing. Consequently, the cutting edges tend to become dull quickly, and it may be necessary to resharpen the cutter once or twice during the machining process of the same batch of parts. If the rake angle of the hobbing cutter is not properly controlled during grinding, the tooth profile can easily deform. As a result, the machined tooth profile will no longer conform to the standard involute curve, leading to instantaneous acceleration during operation. Such unstable motion inevitably causes vibrations and noise.

　　The above is an introduction to the causes of noise from construction hoists. We hope you find it helpful.