Seven forward speeds and three reverse speeds are realized by combining two compound planetary gear sets using three clutches and four brakes, and each shift speed is realized by operating two frictional elements, thereby reducing a capacity of a hydraulic pump and enhancing an efficiency of a hydraulic pressure control by realizing each shift speed by operating two frictional elements. A first shift portion and a second shift portion are disposed on the same shaft axis. The first shift portion includes a first planetary gear set formed as a double pinion planetary gear set and a second planetary gear set formed as a single pinion planetary gear set, and the second shift portion includes a third planetary gear set formed as a single pinion planetary gear set and a fourth planetary gear set formed as a single pinion planetary gear set. The first shift portion is combined by two clutches and two brakes, and the second shift portion is combined by one clutch and two brakes.
A power train of an automatic transmission that realizes seven forward speeds and two reverse speeds includes a first planetary gear set a second planetary gear set; a third planetary gear set an input shaft; an output gear; and a transmission case. A third planet carrier is fixedly connected to a first ring gear, a second ring gear is fixedly connected to the a planet carrier, a long-pinion-side ring gear acts as an input element by being fixedly connected to the input shaft, and a second planet carrier acts as an output element by being fixedly connected to the output gear. Also, a second ring gear is variably connected to the input shaft via a first clutch, a first sun gear is variably connected to the first planet carrier via a second clutch, the second sun gear is variably connected to the first sun gear via a third clutch, and the short-pinion-side ring gear is variably connected to the transmission case via a first brake.
A power train of an automatic transmission realizing seven forward speeds and three reverse speeds includes an input shaft, a transmission case, a speed reduction unit including an output unit, a first clutch, a second clutch, a second brake, a third brake, and a fourth brake. The output unit generates seven forward speeds and three reverse speeds at the shift speed output member by operations of the first and second variable input members and third and fourth variably stopped members in response to operation of the clutches and brakes.
A power train of an automatic transmission realizing seven forward speeds and three reverse speeds includes an input shaft, an output gear, a transmission case, a speed reduction unit, an output unit, a first clutch, a second clutch, a third clutch, a fourth clutch, a first brake, and a second brake.The output unit includes variable input members and variably stopped members. the variable input members and variably stopped members are controlled by the clutches to realize seven forward speed and three reverse speeds at the output unit.
An automatic transmission includes a planetary gear train of first, second, third and fourth planetary gears; an input rotation member connected with a ring gear of the second planetary gear; and a first connection member connecting a carrier of the second planetary gear and a ring gear of the fourth planetary gear. A first rotation sensor senses the rotation speed of the first connection member. A second rotation sensor senses the rotation speed of one rotating element of the first and second planetary gears. A processing section calculates an input speed of the automatic transmission from the rotation speeds sensed by the first and second rotation sensors.
