Patent ID: 6905434
Filing Date: 2005-06-14
Classification: F16H

Abstract:
1. A speed change mechanism of an automatic transmission for achieving 6-forward speed positions and one reverse position, comprising: an input shaft adapted to be driven by a power source; an output shaft coaxially arranged with the input shaft; a first planetary gear unit which converts an input rotation from the input shaft to an output rotation whose speed is lower than that of the input rotation; and a first unit including second and third planetary gear units and arranged between the first planetary gear unit and the output shaft, the first unit being arranged to provide, by managing the output rotation from the first planetary gear unit, the output shaft with seven types of rotation which respectively correspond to the 6-forward speed positions and one reverse positions, the third planetary gear unit including a pinion carrier connected to a ring gear of the second planetary gear unit, wherein one of the second and third planetary gear units is of a double ring type which comprises a sun gear powered by the first planetary gear unit, inside and outside ring gears concentrically disposed around the sun gear, pinions each being meshed with the sun gear and the inside and outside ring gears, and a pinion carrier carrying the pinions, the pinion carrier being connected to the output shaft to rotate therewith; and a second unit arranged between the first planetary gear unit and the first unit to manage a power transmission therebetween.