Six-speed powertrain of automatic transmission

A six-speed powertrain of an automatic transmission formed by combining a first simple planetary gear set including a first sun gear, a first ring gear, and a first planet carrier as operational elements thereof, a second simple planetary gear set including a second sun gear, a second ring gear, and a second planet carrier as operational elements thereof, and a third simple planetary gear set including a third sun gear, a third ring gear, and a third planet carrier as operational elements thereof,

• wherein the first, the second, and the third simple planetary gear sets are disposed in a sequence of the first simple planetary gear set, the third simple planetary gear set, and the second simple planetary gear set from an engine side connected to the input shaft,
• the first and second simple planetary gear sets are formed as single pinion planetary gear sets,
• the third simple planetary gear set is formed as a double pinion planetary gear set,
• the first sun gear is fixedly connected to a transmission case so as to always act as a fixed element,
• the first ring gear is fixedly connected to an input shaft so as to always act as an input element,
• the second sun gear is fixedly connected to the first planet carrier,
• a second planetary gear is connected with a third planetary gear by a common planet carrier so as to rotate separately with the third planetary gear,
• the third sun gear is variably connected to the transmission case through the second brake,
• the third planet carrier acts as an output element, the third ring gear is variably connected to the second ring gear through the first clutch,
• the third sun gear of the double pinion planetary gear set with the second sun gear is variably connected to the first planet carrier of the first single pinion planetary gear set through the second clutch, and
• the third ring gear is variably connected to the input shaft through the third clutch so as to act as a variable input element and is variably connected to the transmission case through the first brake and the one-way clutch disposed in parallel with each other.

A six-speed powertrain of an automatic transmission formed by combining a first simple planetary gear set including a first sun gear, a first ring gear, and a first planet carrier as operational elements thereof, a second simple planetary gear set including a second sun gear, a second ring gear, and a second planet carrier as operational elements thereof, and a third simple planetary gear set including a third sun gear, a third ring gear, and a third planet carrier as operational elements thereof,

• wherein the first, the second, and the third simple planetary gear sets are disposed in a sequence of the first simple planetary gear set, the third simple planetary gear set, and the second simple planetary gear set from an engine side connected to the input shaft,
• the first and third simple planetary gear sets are formed as first and second double pinion planetary gear sets,
• the second simple planetary gear set is formed as a single pinion planetary gear set,
• the first sun gear is fixedly connected to a transmission case so as to always act as a fixed element,
• the first planet carrier is fixedly connected to an input shaft so as to always act as an input element,
• the second sun gear is fixedly connected to the first ring gear,
• a second planetary gear of the single pinion planetary gear set is connected with a third planetary gear by a common planet carrier so as to rotate separately with the third planetary gear,
• the third sun gear is variably connected to the transmission case through the second brake,
• the third planet carrier acts as an output element,
• the third ring gear is variably connected to the second ring gear through the first clutch, is variably connected to the first ring gear through the second clutch with the second sun gear, is variably connected to the input shaft through the third clutch, acts as a variable input element, and is variably connected to the transmission case through the first brake and the one-way clutch disposed in parallel with each other.