Patent ID: 6802795
Filing Date: 2004-10-12
Classification: F16H

Abstract:
An automatic transmission of a motor vehicle, comprising:an input member; an output member; an auxiliary power transmitting portion including a planetary gear set having three rotating elements, wherein when one of the three rotating elements is coupled to and rotated with the input member, and another one of the rotating elements is fixed to be inhibited from rotating, the remaining rotating element serving as an intermediate rotating element is rotated at a reduced speed as compared with that of the input member, the auxiliary power transmitting portion further including an intermediate rotation output friction device that is operable, when engaged, to permit the intermediate rotating element to output rotary power at the reduced speed; and a main power transmitting portion including a plurality of planetary gear sets including sun gears, carriers and ring gears, parts of which are coupled to each other to provide a first rotating element, a second rotating element, a third rotating element, a fourth rotating element and a fifth rotating element, which are arranged in the order of description from one end to the other end in a nomogram in which speeds of rotation of the first, second, third, fourth and fifth rotating elements are represented by straight lines, the main power transmitting portion further including a first brake, a second brake, a first clutch and a second clutch, wherein the first rotating element is selectively coupled to the input member via the second clutch and is selectively inhibited from rotating by the second brake, the second rotating element is selectively inhibited from rotating by the first brake, the third rotating element is selectively coupled to the input member via the first clutch, the fifth rotating element is coupled to or selectively coupled to the intermediate output member, and the fourth rotating element is coupled to the output member so as to output rotary power from the main power transmitting portion, wherein a first-speed gear stage having the largest gear ratio is established when the intermediate rotation output friction device and the first brake are engaged, a second-speed gear stage having a smaller gear ratio than that of the first-speed gear stage is established when the intermediate rotation output friction device and the second brake are engaged, a third-speed gear stage having a smaller gear ratio than that of the second-speed gear stage is established when the second clutch and the intermediate rotation output friction device are engaged, a fourth-speed gear stage having a smaller gear ratio than that of the third-speed gear stage is established when the first clutch and the intermediate rotation output friction device are engaged, a fifth-speed gear stage having a smaller gear ratio than that of the fourth-speed gear stage is established when the first clutch and the second clutch are engaged, a sixth-speed gear stage having a smaller gear ratio than that of the fifth-speed gear stage is established when the first clutch and the second brake are engaged, and a seventh-speed gear stage having a smaller gear ratio than that of the sixth-speed gear stage is established when the first clutch and the first brake are engaged.