| 主权项 |
1. An automatic transmission comprising:
an input shaft to which power generated by a power source is input; first and second planetary gear sets of a single pinion type; frictional engagement elements including first and second brakes; and an output, wherein the first planetary gear set has:
a first sun gear to which the power from the power source is input via the input shaft;a first ring gear engaged with the first brake; anda first carrier, the second planetary gear set has:
a second ring gear always engaged with the first carrier;a second sun gear engaged with the second brake; anda second carrier engaged with the output, the automatic transmission is configured to engage the first and second brakes in a first gear to allow the power from the power source to be transmitted to the output via the input shaft and the first and second planetary gear sets, the automatic transmission further comprises:
a third planetary gear set of a double pinion type having a third sun gear, a third carrier, and a third ring gear; anda fourth planetary gear set of the single pinion type having a fourth sun gear, a fourth carrier, and a fourth ring gear, the input shaft and the fourth carrier are always engaged with each other, the first sun gear and the third carrier are always engaged with each other, the third sun gear and the fourth ring gear are always engaged with each other, the second sun gear and the fourth sun gear are always engaged with each other, and the frictional engagement elements further include:
a first clutch engaging and disengaging the second carrier with and from the third ring gear;a second clutch engaging and disengaging the input shaft with and from the first sun gear and the third carrier; and a third clutch engaging and disengaging the third sun gear with and from the third ring gear, or the third carrier with and from the third ring gear, or the third sun gear with and from the third carrier. |
