Reducing Gear Drive Noise
Noise is one of the most challenging aspects of engineering. To reduce the risk of noise-induced hearing damage and to improve the potential of hearing protection, engineers are continuously looking for ways to limit the amount of noise created by gear drives. This paper will discuss the sources of gear noise and provide potential engineering solutions to reduce the amount of noise generated.
The noise created by a gear drive is largely composed of vibration and structure-borne noise. Vibration-induced noise occurs because of the relative motion between different components and is caused by the varying velocity and acceleration of the tooth contact pattern. This phenomenon results in air-borne noise such as clatter and shake. Structure-borne noise is created by the input and output torques that interact with the transmission components, resulting in the excitation of not only the driven components but also the mounting structure. This structure-borne noise also reflects internally through the transmission, causing additional air-borne noise to be produced.
Since the source of noise is created through vibrations and displacement, a logical approach to reduce the noise produced by any gear drive is to reduce the vibration levels. Firstly, it is important to select the right components when designing a system. This includes selecting components made of materials with higher damping characteristics. In addition, by optimizing the operating parameters, such as lubrication, contact ratio and mesh alignment, the transition between tooth contact movement will be smoother and therefore more silent. Since increased contact between components increases the transmission’s damping, modifying the shape of the tooth surface by chamfering or adding serrations can also reduce the excitations that cause the noise.
In order to reduce the amount of structure-borne noise, the following approaches should be taken into consideration. Shock mountings and bellows are some of the oratorical methods used to minimize the noise generated by the transmission components. If possible, it is also recommended to reduce the excitation by damping the torque input and output. This can be done by adding dampers to the drive shaft or by correcting the base plate design so it can absorb potentially harmful resonances. Another option is to increase the stiffness of the transmission components and by doing so, diffusing the energy throughout the transmission.
In summary reducing the amount of noise generated by a gear drive can be achieved in a variety of ways. The main focus of this reduction should be on the vibration produced by the drive. This can be done by selecting components with higher damping characteristics, properly aligning the mesh structure and optimizing the operating parameters. In addition, structure-borne noise can be minimized by introducing shock mountings and damping elements. With the proper design and application engineering, significant noise reduction can be achieved from any gear drive system.
