Planetary gearboxes are a common type of transmission device, and helical and spur gears are two common types of gears used in planetary gearboxes. They differ in appearance, support structure, precision, noise, and manufacturing.
Firstly, visual difference
In terms of appearance, helical gears are gears placed in a staggered manner on cylindrical gears, while spur gears are not staggered. This visual difference directly affects their working principles and performance.
Secondly, the support structure of the planetary gearbox also differs
The planetary carrier of a helical gear planetary gearbox must use a double support structure to support it, while the planetary carrier of a spur gear planetary gearbox can be single or double supported. However, helical gears have higher precision than spur gears, so the precision of helical gear planetary gearboxes is higher.
Furthermore, noise is also one of their differences
Spur gear planetary gearboxes produce vibrations, leading to higher noise, while the noise of helical gears is slightly lower. This is because spur gears may undergo some regular, once-per-tooth excitation due to some changes in the involute profile of the entire tooth surface at the same time, causing vibration and noise.
In addition, the manufacturing
The manufacturing and assembly of spur gears also present difficulties and economic issues because they need to be manufactured as a single, continuous gear with teeth along the helix, while helical gears are relatively easier to manufacture.
Finally, although helical gears may cause adverse axial forces, the benefits they bring in terms of vibration and strength far outweigh the disadvantages of axial thrust and slightly increased manufacturing costs. Therefore, using helical gears instead of spur gears is more suitable in the manufacturing of gearboxes.
In conclusion, helical and spur gears in planetary gearboxes differ significantly in appearance, support structure, precision, noise, and manufacturing. The choice of the appropriate gear type depends on specific application requirements and performance needs.