Planetary Gear Set
The planetary gear set enables the transmission to provide a drive torque in two directions, forward and reverse, to the drive shafts. Engine torque always enters the transmission through the planet carrier via the input shaft. This carrier can be directly connected to the sun-wheel by the forward multi-plate clutches. When it does, the epicyclic gear set rotates as one unit, and engine torque is transmitted directly to the primary pulley. The planet gears do not transmit any torque, therefore no mechanical loss will occur in the planetary gear set and the primary pulley will rotate in the same direction as the engine. This is the forward drive mode.
In reverse mode, the annulus of the planetary gear set is held stationary by the reverse multi-plate clutches. Three pairs of planet gears are driven by the planet carrier, forcing the sun-wheel to rotate in the opposite direction.