Automatic transmission for a vehicle

Abstract

A multi-speed automatic transmission improves transmission efficiency by reducing drag loss due to high speed rotation of a freely rotating element of a planetary gear set. An automatic transmission for a vehicle includes: an input path T1 of a first speed ratio; an input path T2 which has a larger speed ratio than this input path T1; a planetary gear set of four elements, wherein the four elements are a first element, a second element, a third element, and a fourth element following an order of elements on a speed diagram; a clutch C-2 transmitting a rotation of the input path T2 to the first element S3; a clutch C-1 transmitting the rotation from the input path T2 to the fourth element S2; a clutch C-4 transmitting a rotation from the input path T1 to the first element; a clutch C-3 transmitting the rotation from the input path T1 to the second element C3; a brake B-1 engaging the fourth element; a brake B-2 engaging the second element; and an output member coupled with the third element R3. Accordingly, drag resistance is prevented from increasing because no extremely high speed rotation of the freely rotating element is generated, even when a speed is achieved using any combination of the engagement elements.

Dependencies are inferred from the claim text.