HOW EPICYCLIC GEARBOXES WORK

1a Apply rotation to sun gear

Applying rotation to the sun gear in turn rotates the planetary pinions on their carrier, but with the carrier held by a brake band, the annulus ring gear rotates.

1c Direct drive

Inputting rotational power equally to the sun gear and annulus by placing a brake band between them, prevents the planetary pinions from rotating and therefore the planetary carrier turns with them in direct drive.

1b Rotate pinions and carrier

Inputting rotational power to the annulus ring gear while holding the sun gear with a brake band, in turn rotates the planetary pinions and the planetary carrier.

2 Epicyclic gearbox

The line of drive through an epicyclic gearbox is hugely complex but essentially involves brake bands (B1, B2, B3) locking the various gear annulus (I1, I2, I3). Rotational power is driven through the input shaft to the sun gears (S1, S2) turning planetary pinions (P1, P2), which rotates planetary carrier (A), which is connected to the output shaft (D). Engine power goes through sun gear (S2) while power outputs via planet carrier A to the output shaft. The line of drive can be followed through by applying the brake bands, with the top 1:1 ratio applied by sliding splined male cone clutch (G) into female counterpart (F), locking the whole drive together.