Planetary gear shafts can reduce the contact stress of individual gears, which is reflected in the following aspects:
1. Multi gear load sharing
In a planetary gear system, multiple planetary gears simultaneously mesh with the sun gear and ring gear, allowing the transmitted load to be evenly distributed across multiple gears, reducing the bearing pressure and contact stress of a single gear.

2. Uniform mechanical distribution
The planetary gear shaft connects multiple planetary gears, and through the support of the shaft, the gear meshing is more stable and uniform, avoiding local force concentration and reducing the peak contact stress on the gear surface.

3. Improve gear life
Due to the reduced contact stress borne by a single gear, the speed of gear wear and fatigue slows down, extending the service life of the gear and the entire transmission system.

4. Reduce the risk of tooth surface damage
The reduction of contact stress effectively reduces the risk of damage such as pitting and microcracks on the tooth surface, and improves the reliability of the transmission system.

5. Improve transmission efficiency
Reducing contact stress means a smoother meshing process, reduced friction losses, and is beneficial for improving the efficiency and stability of the entire transmission system.