Patent ID: 7988589
Filing Date: 2011-08-02
Classification: F16H

Abstract:
1. A gear train of an automatic transmission for a vehicle, comprising: a first planetary gear set that is a simple planetary gear set and comprises a first rotational element that is connected to a transmission housing and operated as a fixed element, a second rotational element that forms an intermediate output path outputting a reduced rotational speed of an input shaft, and a third rotational element that is directly connected with the input shaft and forms an input path; a second planetary gear set that is formed by combining first and second simple planetary gear sets, has four rotational elements, and comprises: a plurality of friction members including clutches and brakes that selectively connect the rotational elements of the first and second planetary gear sets to each other or to the transmission housing; wherein the first planetary gear set is a single pinion planetary gear set, the first rotational element is a first sun gear, the second rotational element is a first planet carrier, and the third rotational element is a first ring gear; the first simple planetary gear set of the second planetary gear set is a single pinion planetary gear set comprising a second sun gear, a second planetary carrier, and a second ring gear, and the second simple planetary gear set of the second planetary gear set is a double pinion planetary gear set comprising a third sun gear, a third planetary carrier, and a third ring gear; and the fourth rotational element is the third sun gear, the fifth rotational element is the second ring gear, the sixth rotational element is the second planet carrier and the third ring gear, and the seventh rotational element is the second sun gear and the third planet carrier.