The Ravigneaux gear train,
like the Simpson gear train, provides gear reductions, overdrives,
direct drive, and reverse combination. It offers the following
advantages:
- Torque loading capacity
is increased due to greater tooth contact area.
- It is very compact unit
in comparison to the Simpson gear train.
- It can have the large
sun gear, planetary carrier, or ring gear as the output member.
The Ragvineaux gear train
uses two sun gears, one small and one large, and two sets of planetary
pinion gears, three long pinions and three short pinions. The planetary
pinion gears rotate on their own shafts, which are fastened to a common
planetary carrier. The small sun gear is meshed with the short planetary
pinion gears. These short pinions act as idler gears to drive the long
planetary pinion gears. The long planetary pinion gears mesh with the
large sun gear and the ring gear. A single ring gear surrounds the
complete assembly.