COMPOUND PLANETARY GEAR SET AND GEAR TRAIN HAVING COMPOUND PLANETARY GEAR SET

摘要

PURPOSE: A compound planetary gear set and a gear train having the compound planetary gear set are provided to change the power of an engine into the output of forward 4-speed and reverse 1-speed by integrating first and second planetary gears having different diameters, to keep the ratio of gear levels almost same, and to control the compound planetary gear set with only at least four friction elements. CONSTITUTION: A compound planetary gear set(200) and a gear train having the compound planetary gear set are composed of a single planetary gear part(210), a double planetary gear part(220), and a planet carrier(230). The single planetary gear part includes a first sun gear(211); a plurality of first planetary gears(213) circumscribed and engaged with the first sun gear; and a first ring gear(217) inscribed and engaged with the first planetary gears. The double planetary gear part comprises a second sun gear(221); a plurality of second planetary gears(223) circumscribed and engaged to the second sun gear and directly connected to the first planetary gears with a diameter shorter than the first planetary gear; a plurality of third planetary gears(225) circumscribed and engaged to the second planetary gears; and a second ring gear(227) inscribed and engaged to the third planetary gears. The planet carrier rotatively supports the first, second, and third planetary gears.