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US 8,574,112 B2Granted
Gear train of automatic transmission for vehicles
AssigneeHyundai Motor Company
InventorWoo-Yeol Kim
Life of this patent
Estimating the term…
Abstract
A gear train of an automatic transmission for vehicles realizes at least eight forward speeds and two reverse speeds by combining three simple planetary gear sets with four clutches and two brakes. In addition, two friction elements are operated at each shift-speed. Therefore, the gear train has advantages of simplifying structures of the automatic transmission and improving power delivery performance and fuel economy.
Claims16
A gear train of an automatic transmission for vehicles, comprising:
- a first planetary gear set having a first sun gear, a first planet carrier, and a first ring gear as rotation elements of the first planetary gear set;
- a second planetary gear set having a second sun gear, a second planet carrier, and a second ring gear as rotation elements of the second planetary gear set;
- a third planetary gear set having a third sun gear, a third planet carrier, and a third ring gear as rotation elements of the third planetary gear set;
- and
- frictional elements including a plurality of clutches and a plurality of brakes, each of the plurality of clutches connecting at least a rotation element of the first, second, and third planetary gear sets to another rotation element of the first, second, and third planetary gear sets or to an input shaft, and each of the plurality of brakes connecting at least a rotation element of the first, second, and third planetary gear sets to a transmission housing,
- wherein the rotation elements of the first planetary gear set are operated as first, second and third rotation elements of the gear train, with the first rotation element always operated as a fixed element, the second rotation element forming a first intermediate output path through which a reduced rotational speed is output, the third rotation element connected to an input shaft thereby forming an input path and the third rotation element forming a second intermediate output path through which a rotational speed of the input shaft is output,
- wherein a rotation element in the rotation elements of the second planetary gear set is fixedly connected to a rotation element in the rotation elements of the third planetary gear set and another rotation element in the rotation elements of the second planetary gear set is selectively connected to another rotation element in the rotation elements of the third planetary gear set such that the second and third planetary gear sets operate as a compound planetary gear set having four rotation elements, and
- wherein the four rotation elements of the operating compound planetary gear set are operated as fourth, fifth, sixth and seventh rotation elements of the gear train, with the fourth rotation element selectively connected to the first or second intermediate output paths and selectively connected to the transmission housing thereby forming a first variable input path so as to be operated as a selective fixed element, the fifth rotation element selectively connected to the input shaft or selectively connected to the transmission housing thereby forming a second variable input path so as to be operated as a selective fixed element, the sixth rotation element connected to an output gear and forming a final output path, and the seventh rotation element fixedly connected to the first intermediate output path thereby forming an intermediate input path,
- wherein each of the first, second and third planetary gear sets is a simple planetary gear set including one sun gear, one planet carrier and one ring gear.
6 more elements
A gear train of an automatic transmission for vehicles comprising:
- a first planetary gear set being a double pinion planetary gear set and having a first sun gear, a first planet carrier, and a first ring gear as rotation elements of the first planetary gear set;
- a second planetary gear set being a double pinion planetary gear set and having a second sun gear, a second planet carrier, and a second ring gear as rotation elements of the second planetary gear set;
- and
- a third planetary gear set being a single pinion planetary gear set and having a third sun gear, a third planet carrier, and a third ring gear as rotation elements of the third planetary gear set, four clutches including first, second, third, and fourth clutches, and two brakes including first and second brakes,
- wherein the first planet carrier is fixedly connected to an input shaft, the first ring gear is fixedly connected to the third sun gear, the second and third ring gears are fixedly connected to each other, the first sun gear is fixedly connected to a transmission housing, and the second planet carrier is fixedly connected to an output gear, and
- wherein the first clutch selectively connects the second planet carrier to the third planet carrier, the second clutch selectively connects the first ring gear to the second sun gear, the third clutch selectively connects the first planet carrier to the second sun gear, the fourth clutch selectively connects the input shaft to the third ring gear, the first brake selectively connects the third ring gear to the transmission housing, and the second brake selectively connects the second sun gear to the transmission housing.
3 more elements
A gear train of an automatic transmission for vehicles comprising:
- a first planetary gear set being a double pinion planetary gear set and having a first sun gear, a first planet carrier, and a first ring gear as rotation elements of the first planetary gear set;
- a second planetary gear set being a single pinion planetary gear set and having a second sun gear, a second planet carrier, and a second ring gear as rotation elements of the second planetary gear set;
- and
- a third planetary gear set being a double pinion planetary gear set and having a third sun gear, a third planet carrier, and a third ring gear as rotation elements of the third planetary gear set, four clutches including first, second, third, and fourth clutches, and two brakes including first and second brakes,
- wherein the first planet carrier is fixedly connected to an input shaft, the first ring gear is fixedly connected to the third sun gear, the second and third planet carriers are fixedly connected to each other, the first sun gear is fixedly connected to a transmission housing, and the second ring gear is fixedly connected to an output gear, and
- wherein the first clutch selectively connects the second ring gear to the third ring gear, the second clutch selectively connects the first ring gear to the second sun gear, the third clutch selectively connects the first planet carrier to the second sun gear, the fourth clutch selectively connects the input shaft to the third planet carrier, the first brake selectively connects the second planet carrier to the transmission housing, and the second brake selectively connects the second sun gear to the transmission housing.
3 more elements
Dependencies are inferred from the claim text.