Overview of gear noise, analysis and causes

1. Overview

Gear noise should be accurately referred to as gear transmission noise, refers to the meshing of gear pairs or gear sets in the transmission, due to the mutual collision or friction provoked by the gear body vibration and radiation out of the noise.

2. Gear noise analysis and causes

Gear noise analysis

In order to reduce the noise of the gear transmission system from the design point of view, we should first analyse the type of gear system noise and the mechanism of occurrence.

In the gear system, according to the different mechanisms, the noise can be divided into two kinds of acceleration noise and self-noise. On the one hand, when the gear teeth mesh, due to the impact of the gear to produce a large acceleration and will cause a disturbance in the surrounding media, the sound radiation generated by this disturbance is known as the acceleration noise of the gear. On the other hand, in the gear dynamic meshing force, the system of the parts will produce vibration, these vibrations generated by the sound radiation is called self-talk noise.

For open gear transmission, acceleration noise is directly radiated from the impact of the gear teeth, and the self-tone noise is radiated from the wheel body, drive shaft, etc. For closed gear transmission, acceleration noise is first radiated to the air and lubricant in the gearbox, and then radiated through the gearbox. Self-echoing noise is caused by the vibration of the gear body through the drive shaft to cause vibration of the support, and thus through the vibration of the gear box wall and radiation out. Generally speaking, self-chirping noise is the main source of sound in closed gear drives. Therefore, the noise intensity of the gear system is not only related to the dynamic excitation force of the gear teeth meshing, but also with the wheel body, drive shaft. Bearings and boxes and other structural forms, dynamic characteristics and dynamic meshing forces in the transmission characteristics between them.

The causes of gear noise

Gear design. Improper selection of parameters, overlap is too small, improperly shaped tooth profile or no shaping, unreasonable gearbox structure, etc. Gear processing error and tooth shape error is too large, tooth side clearance is too large, surface roughness is too large, etc. Gear system and gear box. Eccentricity of assembly, low contact accuracy, poor parallelism of shaft, insufficient stiffness of shaft, bearing and support, poor rotary accuracy of bearing and improper clearance, etc. Other aspects of input torque. Fluctuations in load torque, torsional vibration of the shaft system, balance of the motor and other drive pairs, etc.