Wind Turbine Part I: Planetary Gear

This example studies a basic planetary gear consisting of three elements: sun gear, planet gears and ring gear. It is also the first part of a wind turbine studied in the WindTurbineGearBox example.

The sun gear is located at the center. The planet gears are mounted on a carrier and are revolving around the sun gear. Both systems are located inside the ring gear. The sun and planet gears are outer gears, with external teeth, and the ring gear is an inner gear, with internal teeth.

The theory concerning planetary gears can be found in [1].

Figure 1: Planetary gear.

Figure 1 shows the animation of the model with the naming of the wheels. The power is applied to the carrier, while keeping the ring wheel locked. The output is on the sun wheel. Gear geometries and material properties are specified in the parameters tab. 

Figure 2: Rotational speeds of sun and planet gears.

Figure 2 reveals that the transmission ratio is 5.31 and that there are some vibrations in the sun gear. The possible cause of these vibrations is simultaneous three-gear backlash. Even if the backlashes are minor in single-gear mesh (ring-planetary gears), their magnitudes are multiplied by the transmission ratio. The ripples at the start of the sun gear's motion are also likely caused by backlash, as the gap between the gears initially prevents them from moving in unison with the planet gears.

References

[1]  Wikipedia. "Epicyclic Gearing." :https://en.wikipedia.org/wiki/Epicyclic_gearing.