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Planetary Gearset
Planetary Gearset
Planetary Gearset • A simple simple planeta planetary ry or epicycl epicyclic ic gearset gearset can provi provide de – overdrive, – reverse, – forward reduction, – neutral, and – direct drive ratios.
Planetary Gearset • 3 main main Comp Compon onent ents s – Sun gear with external gear teeth – Carrier
with planetary pinion gears mounted to it
– An internally toothed ring gear or annulus
Planetary gear configuration
Maximum forward reduction
Maximum forward reduction • greatest torque, • lowest speed is produced with the sun gear as input, the ring gear stationary, and the carrier as the output.
Maximum Overdrive
Maximum overdrive • lowest torque, • greatest speed is produced with the carrier as input, the ring gear stationary, and the sun gear as output.
Minimum forward reduction
Minimum forward reduction • good torque • low speed is produced with the ring gear as input, the sun gear stationary, and the carrier as the output
Slow Overdrive
Slow overdrive • lower torque • greater speed is produced with the carrier as input, the sun gear stationary, and the ring gear as output.
Slow Reverse
Slow reverse • opposite output direction • greatest torque • lowest speed is produced with the sun gear as input, the planetary carrier stationary, and the ring gear as output.
Fast Reverse
Fast reverse • opposite output direction • greater torque • low speed is produced with the ring gear as input, the carrier stationary, and the sun gear as output.
Direct Drive
Direct Drive • Direct drive is produced if any two gearset members are locked together.
Neutral Condition
Neutral Condition • With no held or stationary member, there can be no output. The result is a neutral condition.
Planetary Gearset • An automatic transmission does not require a conventional flywheel because the weight of the torque converter provides enough mass to dampen engine vibrations.
Planetary Gearset
Planetary Gearset
Planetary Gearset
Planetary Gearset
SIMPSON GEAR TRAIN • One of the most popular compound planetary design is the Simpson gear set. • Named for its inventor, Howard Woodworth Simpson (1892–1963), an American automotive engineer, the Simpson gear set consists of two simple planetary gear sets that share a common sun gear. • This combination is capable of providing three forward gears, as well as neutral and reverse.
Shift Modes
Shift Modes : P • The engine will only start if the selector is in either the park or neutral position. • In park, the drive shaft is locked so that the drive wheels cannot move.
Shift Modes : R • The reverse gear selector position is used to move the vehicle in reverse. • Reverse usually uses a lower gear ratio than any of the forward gears.
Shift Modes : N •
In the neutral position no torque is being transmitted through the automatic transmission/transaxle.
Shift Modes
: D
• For ordinary driving, the driver moves the selector to the ‘drive’ position. • The transmission starts out in the lowest gear and automatically shifts into higher gears as the car picks up speed.
Shift Modes
: 2
•
The second position is used for slowing the vehicle while descending long grades.
•
In this gear selection, the vehicle speed is controlled and the engine speed is increased to provide engine compression braking.
• This gear selection is used for the gentle grades at a moderate vehicle speed.
Shift Modes •
: L
The first (or low) position is used for slowing the vehicle while descending long grades.
• In this gear selection, the vehicle speed is controlled and the engine speed is increased to provide engine compression breaking. • This gear selection is used for the steepest grades at the lowest possible speed.
Clutch Application Chart
Schematic
Schematic
D 1
Schematic
D 1
Powerflow
D 1
Schematic
D 2
Schematic
D 2
Powerflow
D 2
Schematic
D 3
Schematic
D 3
Powerflow
D 3
Powerflow
D 3
Schematic
R
