Differential Planetary Gears

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Differential Planetary Gears

Differential Gear-Trains

Differential Schematic

Differential Schematic

These are more complex to model because they have two degrees-of-freedom.

Differential Gears use two independent input drives to rotate a single output shaft.


There are two standard variations:

1.Sun and the Carrier are Driving Gears. The Annulus is the Output Gear.  

2.Annulus and the Carrier are Driving Gears. The Sun is the Output Gear.

If you take one as the input and one as the output, the effective gear ratio between them depends on the speed of the third gear.


Differential Gears are frequently used:

to shift the phase of the output shaft relative to the input shaft

to modulate the output speed

where you need a wide gear ratio

QST14-5-1A

tog_minusVARIATION 1: Carrier (C) and Sun (S) as Drivings; Driven Annulus (A)