Noise analysis and treatment methods of planetary gearbox

The noise analysis and treatment method of planetary gearbox is a complex problem involving mechanical design, manufacturing and maintenance. The following is a detailed analysis of the noise of planetary gearbox and the corresponding treatment method:

A. Noise analysis of planetary gearbox

1. Gear system and gearbox

Assembly eccentricity: If there is eccentricity during the assembly process, it will cause poor gear meshing, resulting in noise.

Low contact accuracy: Insufficient contact accuracy of gears will affect the meshing effect of gears and increase noise.

Poor parallelism of shafts: The non-parallelism of shafts will cause additional vibration and noise during the meshing process of gears.

Insufficient stiffness: Insufficient stiffness of shafts, bearings, and supports will cause deformation when subjected to force, thereby causing noise.

Bearing problems: Low rotation accuracy of bearings and improper clearance will also cause noise.

2. Gear design

Improper parameter selection: Improper selection of parameters such as the number of teeth and module will affect the meshing performance of gears.

Small overlap: Small overlap will cause impact of gears during meshing and increase noise.
Improper tooth profile modification: Tooth profile modification is to improve the meshing performance of gears, and improper modification will be counterproductive.
Unreasonable gearbox structure: Unreasonable structure will affect the support and positioning of gears, resulting in increased noise.

3. Gear processing
Base pitch error and tooth profile error: These errors will affect the meshing accuracy of gears and cause noise.
Too large tooth side clearance: Too large tooth side clearance will cause the gear to produce knocking sound during meshing.
Excessive surface roughness: Rough tooth surface will increase friction and vibration, thereby generating noise.

4. Machine maintenance
Poor lubrication: Insufficient lubrication or poor lubricant cleanliness will accelerate gear wear and increase noise.
Load torque fluctuation: Fluctuation of load torque will cause torsional vibration of the shaft system, thereby generating noise.
Balance problems of motors and other transmission pairs: Poor balance will cause vibration and noise.

5. Other factors
Meshing impact between planetary gears and sun gears, gear rings, etc.: Forced vibration generated during meshing will cause noise.
Eccentric unbalanced force: The eccentric unbalanced force during the rotation of the planetary carrier will produce low-frequency vibration and noise.
External exciting force: When the gear is subjected to external exciting force, if its natural frequency is transient free vibration, noise will be generated.

B. Noise treatment method for planetary gearbox

1. Improve assembly quality
Ensure the alignment and parallelism of the gears during assembly.
Increase the stiffness of bearings and supports and reduce deformation.
Check and adjust the bearing clearance regularly to ensure that it is within a reasonable range.

2. Optimize gear design
Reasonably select gear parameters such as the number of teeth, module, etc.
Increase gear overlap and reduce meshing impact.
Appropriately modify the tooth profile to improve meshing performance.
Optimize the gearbox structure to improve support and positioning accuracy.

3. Improve processing accuracy
Strictly control the base pitch error and tooth shape error.
Reduce the tooth side clearance to avoid the generation of impact sound.
Reduce the tooth surface roughness to reduce friction and vibration.

4. Strengthen the maintenance of the whole machine
Regularly check and replace the lubricating oil to ensure that the lubrication is sufficient and clean.
Balance the load torque and reduce the torsional vibration of the shaft system.
Balance the motor and other transmission pairs to reduce vibration and noise.

5. Adopt noise reduction measures
Install a soundproof cover or silencer on the outside of the gearbox.
Wrap or fill the gearbox with silencer material.
Add shock-absorbing elements such as shock pads and shock absorbers to the transmission system.

6. Regular inspection and adjustment
Regularly inspect and maintain the planetary gearbox to detect and deal with potential problems in time.
Adjust the working parameters and status of the gearbox according to the usage to maintain its optimal performance.