The reason for the loud noise in the gearbox

There are four main reasons for high gearbox noise:
1. Internal tooth surface hardness of the reducer
With the development of gear hard tooth surface technology, its characteristics of large load-bearing capacity, small volume, light weight, and high transmission accuracy have made its application fields increasingly widespread. However, the carburization hardening used to obtain hard tooth surfaces causes deformation of the gears, resulting in increased transmission noise and shortened lifespan. To reduce noise, it is necessary to perform precision machining on the tooth surface. At present, in addition to using traditional gear grinding methods, a hard tooth surface scraping method has been developed. By correcting the tooth top and root, or reducing the tooth shape of the driving and passive wheels, the impact of gear meshing and meshing can be reduced, thereby reducing gear transmission noise.

2. The influence of internal gear error on the reducer
The tooth profile error, base pitch deviation, tooth orientation error, and ring gear radial runout error in the gear manufacturing process are the main errors that cause transmission noise in planetary reducers. It is also a problem point in controlling the transmission efficiency of planetary reducers. Here is a brief explanation of tooth profile error and tooth orientation error.

Gears with small tooth profile errors and small tooth surface roughness, under the same test conditions, have a noise level 10 dB lower than ordinary gears. Gears with small pitch errors, under the same test conditions, have a noise level 6 to 12 dB lower than ordinary gears. But if there is tooth pitch error, the impact of load on gear noise will be reduced.

Tooth alignment error will result in transmission power not being transmitted across the full tooth width, and the contact area will turn towards the end face or that end face of the tooth, causing an increase in tooth deflection due to local stress, resulting in an increase in noise level. But under high loads, tooth deformation can partially compensate for tooth alignment errors.

3. Calibration of reducer system indicators
The machining accuracy of components before assembly and the selection method for components (complete exchange, group selection, single piece selection, etc.) will affect the accuracy level of the system after assembly, and its noise level is also within the affected range. Therefore, it is crucial to verify (or calibrate) various indicators of the system after assembly to control system noise.

4. Assembly concentricity and dynamic balance
Inconsistent assembly will lead to imbalanced operation of the shaft system, and due to loose and tight meshing on both sides of the tooth theory, the noise will intensify. The imbalance during the assembly of high-precision gear transmission will seriously affect the accuracy of the transmission system.