Patent ID: 7128683

Claim:
A power transmission mechanism comprising: a first planetary gear including a first sun gear, a first ring gear, and a first planet-pinion carrier carrying a first planet pinion in mesh with the first sun gear, and with the first ring gear; a second planetary gear including a second sun gear, a second ring gear, and a second planet-pinion carrier carrying a second planet pinion in mesh with the second sun gear, and with the second ring gear; a third planetary gear including a third sun gear, a third ring gear, and a third planet-pinion carrier carrying a third planet pinion in mesh with the third sun gear, and with the third ring gear; a fourth planetary gear including a fourth sun gear, a fourth ring gear, and a fourth planet-pinion carrier carrying a fourth planet pinion in mesh with the fourth sun gear, and with the fourth ring gear; a first connection member rigidly coupling the first ring gear, the second planet-pinion carrier, and the fourth ring gear; a second connection member rigidly coupling the third ring gear and the fourth planet-pinion carrier; a third connection member rigidly coupling the first sun gear and the second sun gear; a first clutch selectively connectable between the second ring gear and the third ring gear; a second clutch selectively connectable between the fourth planet-pinion carrier and the fourth sun gear; a third clutch selectively connectable between the third sun gear and the fourth sun gear; a first brake operable to hold selectively against rotation the first planet-pinion carrier; a second brake operable to hold selectively against rotation the third sun gear; a third brake operable to hold selectively against rotation the third connection member; a fourth brake operable to hold selectively against rotation the second connection member; an input shaft connected to the second ring gear; and an output shaft connected to the third planet-pinion carrier.