How to reduce the noise of gears?

How to reduce the noise of gears?
When the gear is working, especially under high load and high speed, the noise and vibration caused by the gear rotation are considered to be a great problem. However, the occurrence of noise problems is often caused by multiple reasons. Therefore, it is difficult to find the crux of the problem. Next, it will reveal the key points of how to reduce noise when the gear system is designed.
1. Use high-precision gears
Reduce pitch error, tooth profile error, runout error and lead error. Grinding gear teeth not only improves accuracy, but also improves surface finish.
2. Use gears with better surface finish
Grinding, grinding, honing the tooth surface, or immersing the gear in oil for a period of time can also improve the smoothness of the tooth surface and reduce noise.
3. Ensure the correct contact of the teeth

Convex machining and tooth tip thinning will prevent edge contact. Proper tooth profile modification is also effective.
4. There is enough backlash
Smaller backlash will produce pulse transmission. Overall, a larger backlash will cause fewer problems.
5. Increase the horizontal contact ratio
A greater contact rate will reduce noise. Reducing the pressure angle or increasing the tooth depth will increase the greater contact ratio.
6. Increase the overlap rate
Increasing the overlap rate will reduce noise. Because of this relationship, helical gears are quieter than spur gears. The spiral bevel gear is quieter than the straight bevel gear.
7. Eliminate the interference of tooth profile
For smooth meshing, cut off the top right angle or modify the tooth profile. Smooth meshing without interference will know low noise.
8. Use gears with fewer teeth
Use a gear with a smaller module and a larger number of gear teeth.
9. Use rigid gears
Increasing the tooth surface width will increase rigidity, and this will reduce noise. Strengthening the shell and shaft will increase the stiffness.
10. Use resin materials
Under low load and low speed, plastic gears are quieter. Backlash needs to be considered, because at high temperatures, it will increase due to temperature absorption.
11. Use high shock absorption materials
Compared with rigid gears, cast iron gears have lower noise. Gears with cast iron hubs are also effective.
12. Use proper lubrication
Under hydrodynamic lubrication, sufficient lubrication gear will ensure that the surface is covered with a lubricating film. High viscosity lubrication tends to reduce noise.
13. Lower load and speed
The lowest possible rotation speed and load will reduce gear noise.
14. Use gears without dents
Gears with dents on the tooth surface or tip will produce periodic and irregular noise.
15. Avoid too sparse web
Lightweight gears with thin mesh thickness will produce high-frequency noise. This needs attention