Patent ID: 8152681
Filing Date: 2012-04-10
Classification: F16H

Abstract:
1. A gear train of an automatic transmission for vehicles, comprising: a first planetary gear set being a first simple planetary gear set having three rotational elements, and forming a first input pathway that receives a rotational speed input from an input shaft and outputs an increased rotational speed; a second planetary gear set formed by combining second, third, and fourth simple planetary gear sets such that one rotational element of the second simple planetary gear set is connected to one rotational element of the third simple planetary gear set, another rotational element of the third simple planetary gear set is connected to one rotational element of the fourth simple planetary gear set, and another rotational element of the fourth simple planetary gear set is connected to another rotational element of the second simple planetary gear set to have six rotational elements, and outputting a target speed by using a reduced rotational speed selectively input from the first planetary gear set and the rotational speed of the input shaft input through a second input pathway and first and second variable input pathways; and a plurality of friction members including first, second, and third clutches that are disposed on the first and second variable input pathways, and first, second, and third brakes that selectively connect selected rotational elements of the first and second planetary gear sets to a transmission housing, wherein the second planetary gear set comprises the second simple planetary gear set that is a single pinion planetary gear set and has a second sun gear, a second ring gear, and a second planet carrier as rotational elements thereof, the third simple planetary gear set that is a single pinion planetary gear set and has a third sun gear, a third ring gear, and a third planet carrier as rotational elements thereof, and the fourth simple planetary gear set that is a double pinion planetary gear set and has a fourth sun gear, a fourth ring gear, and a fourth planet carrier as rotational elements thereof, wherein the second planet carrier is connected to the third ring gear, the third planet carrier is connected to the fourth planet carrier, and the fourth ring gear is connected to the second ring gear such that the third sun gear is operated as a fourth rotational element, the second sun gear is operated as a fifth rotational element, the third and fourth planet carriers are operated as a sixth rotational element, the second planet carrier and the third ring gear are operated as a seventh rotational element, the second ring gear and the fourth ring gear are operated as an eighth rotational element, and the fourth sun gear is operated as a ninth rotational element, and wherein the fourth rotational element is selectively connected to the input shaft and the second rotational element through the first variable input pathway and is selectively connected to the transmission housing, the fifth rotational element is selectively connected to the transmission housing, the sixth rotational element is selectively connected to the transmission housing and is selectively connected to the input shaft through the second variable input pathway, the seventh rotational element is connected to an output gear through an output pathway, the eighth rotational element is operated as an idle element, and the ninth rotational element is directly connected to the input shaft through the second input pathway.