Advantages
The planetary gear box offers a set of advantages which makes it an interesting alternative to traditional gear types such as helical and parallel shafts gear boxes.
Especially in applications requiring...
- High Reduction Ratios
Given the same number of teeth Z1 and Z2 the planetary gear offers a higher ratio than the parallel shaft gear.
This makes it possible to obtain...
- Higher ratios with a smaller number of stages
- Stronger dimensions and thereby higher torque handling capacity
- Compact & Light Weight with High Torque Transmission
In a planetary gear the number of teeth in contact is higher than in a spur gear. Therefore, the planetary gear has a superior relation between torque handling capacity and dimensions
- High Radial Loads on Output Shaft
In the planetary gear the internal forces are balanced, i.e. the resulting force is zero. The input and output shafts, therefore, are only transmitting torque.
In a parallel shaft gear, however, the internal forces are not balanced and the shafts must, therefore, support the internal loads.
With the planetary gear it is, therefore, possible to have higher external radial loads on the shafts.
Additional Advantages
- Low Noise Level
Despite the higher number of engaged teeth the noise level remains low as on traditional gear types because the smaller dimensions give lower peripheral velocity on the pitch diameter.
Using input stages with grinded teeth on pinions and satellites combined with nitrided ring gears makes it possible to minimize the noise level of an in-line gearbox (80-85 db at 1 meter).
- High Efficiency
Despite the higher number of engaged teeth the smaller tooth size makes it possible to obtain high efficiencies - typically 0.98 per gear stage.
- Flexible Ratio
The ratio of a planetary stage can easily be modified by changing the sun gear and the reduction group.
The ratio of a multistage gear can easily be adjusted by changing the ration of one or more stages.
