Originally Posted by
FE Hoppy
There is a difference between calling it a "planetary gear-set" and referring to the star gears as planets.
By doing so the poster is incorrectly describing the way the gearing works as planets orbit the sun gear whereas stars do not.
I only corrected the poster as he incorrectly described the gear system while glibly saying "C'mon guys, it's a straightforward Epicyclic sun & planet gear train".
I think we've just got to the stage where we're arguing about definitions, which is rarely productive.
I'd favour this one (my emphases):
"An epicylic gear is a
planetary gear arrangement consisting of
one or more planet (epicyclic) gears meshed and rotating round a central sun gear. The planet gears are also meshed and rotate within an internal ring gear. The planet gears are fixed to a planet carrier-crank arm designed to rotate on the same centre as the sun gear. Only one planet-carrier/crank arm is used in a single epicyclic gear train. This complicated arrangement has a number of modes of operation depending on which members are locked."
The three possible modes of operation are then described as:
Planetary arrangement: The ring gear is fixed
Star arrangement: The planetary arm is fixed
Sun arrangement: The sun gear is fixed
Epicyclic Gears
So it looks like we're all correct.
