The selection of small gears for slewing bearings

When designing the small gear teeth, one of the important parameters is the modulus. The gnawing of the gears produces a gnawing pulsation,which is due to elastic morphing of the deformation of the gear teeth. As one of the basic parameters in designing the gears, modulus of the gears, if very large, (this is to say, the gear has very large size) have relatively big loading capacity.  Modulus , as a parameter, is inversely proportional to the bending degree of gear teeth. If we need increase the modulus, it means we have to increase the stiffness of the gear teeth. This can ensure that the elastic deformation of the gear teeth not get too large when gnawing driving. This greatly reduces the impact of the gear teeth. From this point of view, it’s better increase the modulus appropriately.

However, in manufacturing the gear teeth, the errors are also positively related to the modulus. If the modulus increase, the error of teeth shape and teeth spacing can also become large. At the moment, the gnawing noise also becomes large.

Thus when choosing the modulus, we must take into consideration the specific circumstance. The diameter of the gear is proportional to the number of teeth when the modulus is constant, so the change of the number of teeth will also change the bending amount and elastic stiffness of the gear teeth: The noise generated by the sound source is not only related to the energy of the vibration source, but also has something to do with the size of the radiation area, if the radiation area is increased, the radiation power will also increase.

Thus increase the diameter of the gear teeth will also increase the radiation area of the noise. This will greatly influence the effective control of the gear teeth noise. Therefore, when designing , we should keep the teeth number and the modulus as small as possible, provided the gear teeth stiffness is within the permitted range. We can also choose the materials reasonably and combine it with special heat treatment, in order to increase the gear teeth strength. By this way, we can lower the diameter of the gear teeth and reduce the gear teeth noise.