Planetary gear train of automatic transmission for vehicle

The present application claims priority of Korean Patent Application Number 10-2013-0124730 filed Oct. 18, 2013, the entire contents of which application is incorporated herein for all purposes by this reference.

1. Field of Invention

The present invention relates to an automatic transmission for a vehicle. More particularly, the present invention relates to a planetary gear train of an automatic transmission for a vehicle which can improve power delivery performance and fuel economy.

2. Description of Related Art

Typically, multi-shifts mechanism of an automatic transmission is achieved by combining a plurality of planetary gear sets.

The planetary gear sets receive torque from a torque converter and change and transmit the torque to an output shaft.

It is well known that when a transmission realizes a greater number of shift speeds, speed ratios of the transmission can be more optimally designed, and therefore a vehicle can have economical fuel mileage and better performance. For that reason, an automatic transmission that is able to realize more shift speeds is under continuous investigation.

Though achieving the same number of speeds, the planetary gear train has a different operating mechanism according to a connection between rotational elements (i.e., sun gear, planet carrier, and ring gear).

In addition, the planetary gear train has different features such a durability, power delivery efficiency, and size depend on the layout thereof. Therefore, designs for a combining structure of a gear train are also under continuous investigation.

Currently, four-speed and five-speed automatic transmissions are most often found on the market. However, six-speed automatic transmissions have also been realized for enhancement of performance of power transmission and for enhanced fuel mileage of a vehicle. In addition, eight-speed automatic transmissions and tenth-speed automatic transmissions have been developed at a good pace.

The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

Various aspects of the present invention have been made in an effort to provide a planetary gear train of an automatic transmission for a vehicle having advantages of achieving eleven forward speeds and one reverse speed by combining a plurality of planetary gear sets and a plurality of friction members, and improving power delivery performance and fuel economy by operating three friction members and minimum number of planetary gear sets at each speed.

Various aspects of the present invention provide for a planetary gear train of an automatic transmission for a vehicle that may include: an input shaft receiving torque of an engine; an output shaft outputting changed torque; a first compound planetary gear set having five rotation shafts by combining first and second planetary gear sets and firstly changing torque input through one input path and two variable input paths into six speeds; a second compound planetary gear set having four rotation shaft by combining third and fourth planetary gear sets, secondly changing the six speeds input from the first compound planetary gear set and a rotation speed of the input shaft input through one variable input path into eleven forward speeds and reverse speed, and finally outputting the changed rotation speed, wherein any one rotation shaft of the first compound planetary gear set is directly connected to any one rotation shaft of the second compound planetary gear set; and friction members including clutches interposed between any two rotation shafts or between any one rotation shaft and the input shaft, and brakes interposed between any one rotation shaft and a transmission housing.

The first compound planetary gear set may be formed by combining a first planetary gear set being a single pinion planetary gear set and including a first sun gear, a first planet carrier and a first ring gear, and a second planetary gear set being a double pinion planetary gear set and including a second sun gear, a second planet carrier and a second ring gear, and may include a first rotation shaft including the first sun gear and selectively connected to the input shaft or the transmission housing, a second rotation shaft including the first planet carrier and the second planet carrier, and selectively connected to the input shaft or the transmission housing, a third rotation shaft including the first ring gear and forming an intermediate output path, a fourth rotation shaft including the second ring gear and selectively connected to the third rotation shaft, and a fifth rotation shaft including the second sun gear and directly connected to the input shaft so as to be always operated as an input element.

The second compound planetary gear set may be formed by combining a third planetary gear set being a single pinion planetary gear set and including a third sun gear, a third planet carrier and a third ring gear, and a fourth planetary gear set being a single pinion planetary gear set and including a fourth sun gear, a fourth planet carrier and a fourth ring gear, and may include a sixth rotation shaft including the third ring gear and selectively connected to the transmission housing, a seventh rotation shaft including the third planet carrier and the fourth ring gear and operated as a final output element, and an eighth rotation shaft including the fourth planet carrier and selectively connected to the input shaft, wherein the third rotation shaft further includes the third and fourth sun gear.

The friction members may include: a first clutch selectively connecting the third rotation shaft with the fourth rotation shaft; a second clutch selectively connecting the input shaft with the second rotation shaft; a third clutch selectively connecting the input shaft with the eighth rotation shaft; a fourth clutch selectively connecting the input shaft with the first rotation shaft; a first brake selectively connecting the second rotation shaft with the transmission housing; a second brake selectively connecting the first rotation shaft with the transmission housing; and a third brake selectively connecting the sixth rotation shaft with the transmission housing.

The first clutch and the first and third brakes may be operated at a first forward speed, the first clutch and the second and third brakes may be operated at a second forward speed, the first and second clutches and the third brake may be operated at a third forward speed, the second clutch and the second and third brakes may be operated at a fourth forward speed, the second and third clutches and the third brake may be operated at a fifth forward speed, the second and third clutches and the second brake may be operated at a sixth forward speed, the first, second, and third clutches may be operated at a seventh forward speed, the first and third clutches and the second brake may be operated at an eighth forward speed, the first and third clutches and the first brake may be operated at a ninth forward speed, the third clutch and the first and second brakes may be operated at a tenth forward speed, the third and fourth clutches and the first brake may be operated at an eleventh forward speed, and the fourth clutch and the first and third brakes may be operated at a reverse speed.

Various aspects of the present invention provide for a planetary gear train of an automatic transmission for a vehicle that may include: an input shaft receiving torque of an engine; an output shaft outputting changed torque; a first compound planetary gear set formed by combining a first planetary gear set being a single pinion planetary gear set and a second planetary gear set being a double pinion planetary gear set; a second compound planetary gear set formed by combining third and fourth planetary gear sets being single pinion planetary gear sets; a first rotation shaft including a first sun gear and selectively connected to the input shaft or the transmission housing; a second rotation shaft including a first planet carrier and a second planet carrier, and selectively connected to the input shaft or the transmission housing; a third rotation shaft including a first ring gear, a third sun gear and a fourth sun gear; a fourth rotation shaft including a second ring gear and selectively connected to the third rotation shaft; a fifth rotation shaft including a second sun gear and directly connected to the input shaft so as to be always operated as an input element; a sixth rotation shaft including the third ring gear and selectively connected to the transmission housing; a seventh rotation shaft including a third planet carrier and a fourth ring gear and operated as a final output element; an eighth rotation shaft including a fourth planet carrier and selectively connected to the input shaft; and friction members including clutches interposed between any two rotation shafts or between any one rotation shaft and the input shaft, and brakes interposed between any one rotation shaft and a transmission housing.

The friction members may include: a first clutch selectively connecting the third rotation shaft with the fourth rotation shaft; a second clutch selectively connecting the input shaft with the second rotation shaft; a third clutch selectively connecting the input shaft with the eighth rotation shaft; a fourth clutch selectively connecting the input shaft with the first rotation shaft; a first brake selectively connecting the second rotation shaft with the transmission housing; a second brake selectively connecting the first rotation shaft with the transmission housing; and a third brake selectively connecting the sixth rotation shaft with the transmission housing.

The first clutch and the first and third brakes may be operated at a first forward speed, the first clutch and the second and third brakes may be operated at a second forward speed, the first and second clutches and the third brake may be operated at a third forward speed, the second clutch and the second and third brakes may be operated at a fourth forward speed, the second and third clutches and the third brake may be operated at a fifth forward speed, the second and third clutches and the second brake may be operated at a sixth forward speed, the first, second, and third clutches may be operated at a seventh forward speed, the first and third clutches and the second brake may be operated at an eighth forward speed, the first and third clutches and the first brake may be operated at a ninth forward speed, the third clutch and the first and second brakes may be operated at a tenth forward speed, the third and fourth clutches and the first brake may be operated at an eleventh forward speed, and the fourth clutch and the first and third brakes may be operated at a reverse speed.

The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description, which together serve to explain certain principles of the present invention.

FIG. 1 is a schematic diagram of an exemplary planetary gear train according to the present invention.

FIG. 2 is an operational chart of friction members at each shift-speed applied to an exemplary planetary gear train according to the present invention.

FIG. 3 is a lever diagram for an exemplary planetary gear train according to the present invention.

Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims.

Description of components that are not necessary for explaining the various embodiments will be omitted, and the same constituent elements are denoted by the same reference numerals in this specification.

In the detailed description, ordinal numbers are used for distinguishing constituent elements having the same terms, and have no specific meanings

FIG. 1 is a schematic diagram of a planetary gear train according to various embodiments of the present invention.

Referring to FIG. 1 , a planetary gear train according to various embodiments of the present invention includes first, second, third and fourth planetary gear sets PG 1 , PG 2 , PG 3 and PG 4 disposed on the same axis, an input shaft IS, an output shaft OS, eight rotation shafts TM 1 -TM 8 directly connecting rotation elements of the first, second, third and fourth planetary gear sets PG 1 , PG 2 , PG 3 and PG 4 , seven friction members C 1 -C 4 and B 1 -B 3 and a transmission housing H.

A torque input from the input shaft IS is changed by the first, second, third and fourth planetary gear sets PG 1 , PG 2 , PG 3 and PG 4 , and the changed torque is output through the output shaft OS.

In addition, the planetary gear sets are disposed in a sequence of the first, second, third and fourth planetary gear sets PG 1 , PG 2 , PG 3 and PG 4 from a front portion close to an engine to a rear portion.

The input shaft IS is an input member, and torque from a crankshaft of the engine is changed through a torque converter and is input to the input shaft IS.

The output shaft OS is an output member and drives a driving wheel through a differential apparatus.

The first planetary gear set PG 1 is a single pinion planetary gear set, and includes a first sun gear S 1 , a first planet carrier PC 1 rotatably supporting a first pinion P 1 externally meshed with the first sun gear S 1 , and a first ring gear R 1 internally meshed with the first pinion P 1 as rotation elements thereof.

The second planetary gear set PG 2 is a double pinion planetary gear set, and includes a second sun gear S 2 , a second planet carrier PC 2 rotatably supporting a second pinion P 2 externally meshed with the second sun gear S 2 , and a second ring gear R 2 internally meshed with the second pinion P 2 as rotation elements thereof.

The third planetary gear set PG 3 is a single pinion planetary gear set, and includes a third sun gear S 3 , a third planet carrier PC 3 rotatably supporting a third pinion P 3 externally meshed with the third sun gear S 3 , and a third ring gear R 3 internally meshed with the third pinion P 3 .

The fourth planetary gear set PG 4 is a single pinion planetary gear set, and includes a fourth sun gear S 4 , a fourth planet carrier PC 4 rotatably supporting a fourth pinion P 4 externally meshed with the fourth sun gear S 4 , and a fourth ring gear R 4 internally meshed with the fourth pinion P 4 as rotation elements thereof.

The first, second, third and fourth planetary gear sets PG 1 , PG 2 , PG 3 and PG 4 are combined as two compound planetary gear sets CPG 1 and CPG 2 , and changes a rotation speed of the input shaft IS into eleven forward speeds.

The first compound planetary gear set CPG 1 is formed by combining the first and second planetary gear sets PG 1 and PG 2 , and the second compound planetary gear set CPG 2 is formed by combining the third and fourth planetary gear sets PG 3 and PG 4 .

The first compound planetary gear set CPG 1 has five rotation elements by connecting the first planet carrier PC 1 with the second planet carrier PC 2 .

In addition, the second compound planetary gear set CPG 2 has four rotation elements by directly connecting the third sun gear S 3 with the fourth sun gear S 4 and directly connecting the third planet carrier PC 3 with the fourth ring gear R 4 .

In addition, one rotation element of the first compound planetary gear set CPG 1 is directly connected to one rotation element of the second compound planetary gear set CPG 2 such that the planetary gear train has eight rotation shafts TM 1 -TM 8 .

The first rotation shaft TM 1 includes the first sun gear S 1 and is selectively connected to the input shaft IS and the transmission housing H.

The second rotation shaft TM 2 includes the first planet carrier PC 1 and the second planet carrier PC 2 , and is selectively connected to the input shaft IS and the transmission housing H.

The third rotation shaft TM 3 includes the first ring gear R 1 and the third and fourth sun gears S 3 and S 4 .

The fourth rotation shaft TM 4 includes the second ring gear R 2 and is selectively connected to the third rotation shaft TM 3 .

The fifth rotation shaft TM 5 includes the second sun gear S 2 and is directly connected to the input shaft IS.

The sixth rotation shaft TM 6 includes the third ring gear R 3 and is selectively connected to the transmission housing H.

The seventh rotation shaft TM 7 includes the third planet carrier PC 3 and the fourth ring gear R 4 , and is directly connected to the output shaft OS.

The eighth rotation shaft TM 8 includes the fourth planet carrier PC 4 and is selectively connected to the input shaft IS.

Four clutches C 1 , C 2 , C 3 , and C 4 are disposed between rotation shafts or between rotation shafts and the input shaft IS.

In addition, three brakes B 1 , B 2 , and B 3 is disposed between rotation shafts and the transmission housing H.

The first clutch C 1 is interposed between the third rotation shaft TM 3 and the fourth rotation shaft TM 4 , and selectively causes the third and fourth rotation shafts TM 3 and TM 4 to rotate integrally.

The second clutch C 2 is interposed between the input shaft IS and the second rotation shaft TM 2 , and selectively operates the second rotation shaft TM 2 as an input element.

The third clutch C 3 is interposed between the input shaft IS and the eighth rotation shaft TM 8 , and selectively operates the eighth rotation shaft TM 8 as an input element.

The fourth clutch C 4 is interposed between the input shaft IS and the first rotation shaft TM 1 , and selectively operates the first rotation shaft TM 1 as an input element.

The first brake B 1 is interposed between the second rotation shaft TM 2 and the transmission housing H, and selectively operates the second rotation shaft TM 2 as a fixed element.

The second brake B 2 is interposed between the first rotation shaft TM 1 and the transmission housing H, and selectively operates the first rotation shaft TM 1 as a fixed element.

The third brake B 3 is interposed between the sixth rotation shaft TM 6 and the transmission housing H, and selectively operates the sixth rotation shaft TM 6 as a fixed element.

In addition, a one-way clutch F 1 disposed in parallel with the first brake B 1 between the second rotation shaft TM 2 and the transmission housing H is further included.

The first, second, and third clutches C 1 , C 2 , and C 3 and the first and second brakes B 1 and B 2 are applied to the first compound planetary gear set CPG 1 .

Therefore, the first compound planetary gear set CPG 1 changes torque input through an input path IP and first and second variable input paths VIP 1 and VIP 2 into six speeds by operation of the first and second brakes B 1 and B 2 and the first clutch C 1 and transmits the six speeds to the second compound planetary gear set CPG 2 through an intermediate output path MOP.

At this time, the six speeds include two reduced speeds, speed of 0, speed of 1 the same as the input shaft IS, one increased speed, and one inverse speed.

In addition, the third clutch C 3 and the third brake B 3 are applied to the second compound planetary gear set CPG 2 .

Therefore, the second compound planetary gear set CPG 2 changes torque input through an intermediate input path MIP and a third variable input path VIP 3 into eleven forward speeds and one reverse speed by operation of the third brake B 3 , and outputs the changed torque through a final output path OP.

The friction members consisting of first, second, third, and fourth clutches C 1 , C 2 , C 3 , and C 4 and the first, second, and third brakes B 1 , B 2 , and B 3 are conventional multi-plate friction members of wet type that are operated by hydraulic pressure

FIG. 2 is an operational chart of friction members at each shift-speed applied to a planetary gear train according to various embodiments of the present invention.

Referring to FIG. 2 , three friction members are operated at each speed in the planetary gear train according to various embodiments of the present invention.

The first clutch C 1 , the first brake B 1 , and the third brake B 3 are operated at a first forward speed D 1 .

The first clutch C 1 , the second brake B 2 , and the third brake B 3 are operated at a second forward speed D 2 .

The first clutch C 1 , the second clutch C 2 , and the third brake B 3 are operated at a third forward speed D 3 .

The second clutch C 2 , the second brake B 2 , and the third brake B 3 are operated at a fourth forward speed D 4 .

The second clutch C 2 , the third clutch C 3 , and the third brake B 2 are operated at a fifth forward speed D 5 .

The second clutch C 2 , the third clutch C 3 , and the second brake B 2 are operated at a sixth forward speed D 6 .

The first clutch C 1 , the second clutch C 2 , and the third clutch C 3 are operated at a seventh forward speed D 7 .

The first clutch C 1 , the third clutch C 3 , and the second brake B 2 are operated at an eighth forward speed D 8 .

The first clutch C 1 , the third clutch C 3 , and the first brake B 1 are operated at a ninth forward speed D 9 .

The third clutch C 3 , the first brake B 1 , and the second brake B 2 are operated at a tenth forward speed D 10 .

The third clutch C 3 , the fourth clutch C 4 , and the first brake B 1 are operated at an eleventh forward speed D 11 .

The fourth clutch C 4 , the first brake B 1 , and the third brake B 3 are operated at a reverse speed REV.

It is explained that the first clutch C 1 and the second and third brakes B 2 and B 3 are operated at the first forward speed D 1 , but the one-way clutch F 1 instead of the first brake B 1 is operated at normal driving.

FIG. 3 is a lever diagram for a planetary gear train according to various embodiments of the present invention, and illustrates shift processes of the planetary gear train according to various embodiments of the present invention by lever analysis method.

Referring to FIG. 3 , a lower horizontal line represents a rotation speed of “0”, and an upper horizontal line represents a rotation speed of “1.0”, that is the same rotation speed as the input shaft IS.

Four vertical lies corresponding to the first compound planetary gear set CPG 1 are set as the first rotation shaft TM 1 , the second rotation shaft TM 2 , the third rotation shaft TM 3 or the fourth rotation shaft TM 4 , and the fifth rotation shaft TM 5 from the left to the right in the drawing.

Herein, distances among the first rotation shaft TM 1 , the second rotation shaft TM 2 , the third rotation shaft TM 3 or the fourth rotation shaft TM 4 , and the fifth rotation shaft TM 5 are set according to gear ratios (teeth number of sun gear/teeth number of ring gear) of the first and second planetary gear sets PG 1 and PG 2 .

Since the third rotation shaft TM 3 and the fourth rotation shaft TM 4 are integrally rotated when the first clutch C 1 is operated, the third rotation shaft TM 3 and the fourth rotation shaft TM 4 are disposed on one vertical line.

In addition, four vertical lines corresponding to the second compound planetary gear set CPG 2 are set as the sixth rotation shaft TM 6 , the seventh rotation shaft TM 7 , the eighth rotation shaft TM 8 , and the third rotation shaft TM 3 from the left to the right in the drawing.

Herein, distances among the sixth rotation shaft TM 6 , the seventh rotation shaft TM 7 , the eighth rotation shaft TM 8 , and the third rotation shaft TM 3 are set according to gear ratios (teeth number of sun gear/teeth number of ring gear) of the third and fourth planetary gear sets PG 3 and PG 4 .

Hereinafter, referring to FIG. 2 and FIG. 3 , each speed of the planetary gear train according to various embodiments of the present invention will be described in detail.

First Forward Speed

The first clutch C 1 and the first and third brakes B 1 and B 3 are operated at the first forward speed D 1 .

As shown in FIG. 3 , the rotation speed of the input shaft IS is input to the fifth rotation shaft TM 5 , and the second rotation shaft TM 2 is operated as the fixed element by operation of the first brake B 1 .

Therefore, the rotation elements of the first compound planetary gear set CPG 1 form a first speed line T 1 and a first speed is output through the third rotation shaft TM 3 .

In a state that the first speed is input to the third rotation shaft TM 3 , the sixth rotation shaft TM 6 is operated as the fixed element by operation of the third brake B 3 . Therefore, the rotation elements of the second compound planetary gear set CPG 2 form a first shift line SP 1 .

The first shift line SP 1 crosses the vertical line of the seventh rotation shaft TM 7 that is the output element, and D 1 is output.

Second Forward Speed

The first brake B 1 that was operated at the first forward speed D 1 is released and the second brake B 2 is operated at the second forward speed D 2 .

As shown in FIG. 3 , the rotation speed of the input shaft IS is input to the fifth rotation shaft TM 5 , and the first rotation shaft TM 1 is operated as the fixed element by operation of the second brake B 2 .

Therefore, the rotation elements of the first compound planetary gear set CPG 1 form a second speed line T 2 and a second speed is output through the third rotation shaft TM 3 .

In a state that the second speed is input to the third rotation shaft TM 3 , the sixth rotation shaft TM 6 is operated as the fixed element by operation of the third brake B 3 . Therefore, the rotation elements of the second compound planetary gear set CPG 2 form a second shift line SP 2 .

The second shift line SP 2 crosses the vertical line of the seventh rotation shaft TM 7 that is the output element, and D 2 is output.

Third Forward Speed

The second brake B 2 that was operated at the second forward speed D 2 is released and the second clutch C 2 is operated at the third forward speed D 3 .

As shown in FIG. 3 , the rotation speed of the input shaft IS is input to the fifth rotation shaft TM 5 , and the rotation speed of the input shaft IS is also input to the second rotation shaft TM 2 by operation of the second clutch C 2 . Therefore, the first compound planetary gear set CPG 1 becomes a direct-coupling state and the rotation elements of the first compound planetary gear set CPG 1 form a third speed line T 3 . Therefore, a third speed that is the same as the rotation speed of the input shaft IS is output through the third rotation shaft TM 3 .

In addition, in a state that the third speed in input to the third rotation shaft TM 3 , the sixth rotation shaft TM 6 is operated as the fixed element by operation of the third brake B 3 . Therefore, the rotation elements of the second compound planetary gear set CPG 2 form a third shift line SP 3 .

The third shift line SP 3 crosses the vertical line of the seventh rotation shaft TM 7 that is the output element, and D 3 is output.

Fourth Forward Speed

The first clutch C 1 that was operated at the third forward speed D 3 is released and the second brake B 2 is operated at the fourth forward speed D 4 .

As shown in FIG. 3 , the rotation speed of the input shaft IS is input to the fifth rotation shaft TM 5 , and the rotation speed of the input shaft IS is also input to the second rotation shaft TM 2 by operation of the second clutch C 2 .

At this time, the rotation speed of the input shaft IS is input to the second rotation shaft TM 2 and the first rotation shaft TM 1 is operated as the fixed element by operation of the second brake B 2 in a state that the first clutch C 1 is released. Therefore, the rotation elements of the first compound planetary gear set CPG 1 form a fourth speed line T 4 , and a fourth speed is output through the third rotation shaft TM 3 .

In a state that the fourth speed is input to the third rotation shaft TM 3 , the sixth rotation shaft TM 6 is operated as the fixed element by operation of the third brake B 3 . Therefore, the rotation elements of the second compound planetary gear set CPG 2 form a fourth shift line SP 4 .

The fourth shift line SP 4 crosses the vertical line of the seventh rotation shaft TM 7 that is the output element, and D 4 is output.

Fifth Forward Speed

The second brake B 2 that was operated at the fourth forward speed D 4 is released and the third clutch C 3 is operated at the fifth forward speed D 5 .

As shown in FIG. 3 , the rotation speed of the input shaft IS is input to the fifth rotation shaft TM 5 , and the rotation speed of the input shaft IS is also input to the second rotation shaft TM 2 by operation of the second clutch C 2 .

At this time, the first compound planetary gear set CPG 1 does not affect on shifting since the first and second brakes B 1 and B 2 are not operated.

However, the rotation speed of the input shaft IS is input to the eighth rotation shaft TM 8 by operation of the third clutch C 3 , and the sixth rotation shaft TM 6 is operated as the fixed element by operation of the third brake B 3 . Therefore, the rotation elements of the second compound planetary gear set CPG 2 form a fifth shift line SP 5 .

The fifth shift line SP 5 crosses the vertical line of the seventh rotation shaft TM 7 that is the output element, and D 5 is output.

Sixth Forward Speed

The third brake B 3 that was operated at the fifth forward speed D 5 is released and the second brake B 2 is operated at the sixth forward speed D 6 .

As shown in FIG. 3 , the rotation speed of the input shaft IS is input to the fifth rotation shaft TM 5 , and the rotation speed of the input shaft IS is also input to the second rotation shaft TM 2 by operation of the second clutch C 2 .

At this time, the rotation speed of the input shaft IS is input to the second rotation shaft TM 2 and the first rotation shaft TM 1 is operated as the fixed element by operation of the second brake B 2 in a state that the first clutch C 1 is released. Therefore, the rotation elements of the first compound planetary gear set CPG 1 form the fourth speed line T 4 , and the fourth speed is output through the third rotation shaft TM 3 .

In a state that the fourth speed is input to the third rotation shaft TM 3 , the rotation speed of the input shaft IS is input to the eighth rotation shaft TM 8 by operation of the third clutch C 3 . Therefore, the rotation elements of the second compound planetary gear set CPG 2 form a sixth shift line SP 6 .

The sixth shift line SP 6 crosses the vertical line of the seventh rotation shaft TM 7 that is the output element, and D 6 is output.

Seventh Forward Speed

The second brake B that was operated at the sixth forward speed D 6 is released and the first clutch C 1 is operated at the seventh forward speed D 7 .

As shown in FIG. 3 , the rotation speed of the input shaft IS is input to the fifth rotation shaft TM 5 , and the rotation speed of the input shaft IS is also input to the second rotation shaft TM 2 by operation of the second clutch C 2 . Therefore, the first compound planetary gear set CPG 1 becomes a direct-coupling state and the rotation elements of the first compound planetary gear set CPG 1 form the third speed line T 3 . Therefore, the third speed is output through the third rotation shaft TM 3 .

In addition, in a state that the third speed in input to the third rotation shaft TM 3 , the rotation speed of the input shaft IS is input to the eighth rotation shaft TM 8 by operation of the third clutch C 3 . Therefore, the second compound planetary gear set CPG 2 becomes a direct-coupling state and the rotation elements of the second compound planetary gear set CPG 2 form a seventh shift line SP 7 . Therefore, D 7 is output.

Eighth Forward Speed

The second clutch C 2 that was operated at the seventh forward speed D 7 is released and the second brake B 2 is operated at the eighth forward speed D 8 .

As shown in FIG. 3 , the rotation speed of the input shaft IS is input to the fifth rotation shaft TM 5 , and the first rotation shaft TM 1 is operated as the fixed element by operation of the second brake B 2 .

Therefore, the rotation elements of the first compound planetary gear set CPG 1 form the second speed line T 2 and the second speed is output through the third rotation shaft TM 3 .

In a state that the second speed is input to the third rotation shaft TM 3 , the rotation speed of the input shaft IS is input to the eighth rotation shaft TM 8 by operation of the third clutch C 3 . Therefore, the rotation elements of the second compound planetary gear set CPG 2 form an eighth shift line SP 8 .

The eighth shift line SP 8 crosses the vertical line of the seventh rotation shaft TM 7 that is the output element, and D 8 is output.

Ninth Forward Speed

The second brake B 2 that was operated at the eighth forward speed D 8 is released and the first brake B 1 is operated at the ninth forward speed D 9 .

As shown in FIG. 3 , the rotation speed of the input shaft IS is input to the fifth rotation shaft TM 5 , and the second rotation shaft TM 2 is operated as the fixed element by operation of the first brake B 1 .

Therefore, the rotation elements of the first compound planetary gear set CPG 1 form the first speed line T 1 and the first speed is output through the third rotation shaft TM 3 .

In a state that the first speed is input to the third rotation shaft TM 3 , the rotation speed of the input shaft IS is input to the eighth rotation shaft TM 8 by operation of the third clutch C 3 . Therefore, the rotation elements of the second compound planetary gear set CPG 2 form a ninth shift line SP 9 .

The ninth shift line SP 9 crosses the vertical line of the seventh rotation shaft TM 7 that is the output element, and D 9 is output.

Tenth Forward Speed

The first clutch C 1 that was operated at the ninth forward speed D 9 is released and the second brake B 2 is operated at the tenth forward speed D 10 .

As shown in FIG. 3 , the rotation speed of the input shaft IS is input to the fifth rotation shaft TM 5 , and the third rotation shaft TM 3 is stopped by operation of the first and second brakes B 1 and B 2 .

In a state that the rotation speed of the input shaft IS is input to the eighth rotation shaft TM 8 by operation of the third clutch C 3 , the third rotation shaft TM 3 is stopped. Therefore, the rotation elements of the second compound planetary gear set CPG 2 form a tenth shift line SP 10 .

The tenth shift line SP 10 crosses the vertical line of the seventh rotation shaft TM 7 that is the output element, and D 10 is output.

Eleventh Forward Speed

The second brake B 2 that was operated at the tenth forward speed D 10 is released and the fourth clutch C 4 is operated at the eleventh forward speed D 11 .

As shown in FIG. 3 , the rotation speed of the input shaft IS is input to the fifth rotation shaft TM 5 , and the rotation speed of the input shaft IS is also input to the first rotation shaft TM 1 by operation of the fourth clutch C 4 .

However, the input through the fifth rotation shaft TM 5 does not affect on the shifting, and the input through the first rotation shaft TM 1 affects on the shifting. In addition, the second rotation shaft TM 2 is stopped by operation of the first brake B 1 . Therefore, the rotation elements of the first compound planetary gear set CPG 1 form a fifth speed line T 5 and a fifth speed is output through the third rotation shaft TM 3 .

In a state that the fifth speed is input to the third rotation shaft TM 3 , the rotation speed of the input shaft IS is input to the eighth rotation shaft TM 8 by operation of the third clutch C 3 . Therefore, the rotation elements of the second compound planetary gear set CPG 2 form an eleventh shift line SP 11 .

The eleventh shift line SP 11 crosses the vertical line of the seventh rotation shaft TM 7 that is the output element, and D 9 is output.

Reverse Speed

The fourth clutch C 4 and the first and third brakes B 1 and B 3 are operated at the reverse speed REV.

As shown in FIG. 3 , the rotation speed of the input shaft IS is input to the fifth rotation shaft TM 5 , and the rotation speed of the input shaft IS is also input to the first rotation shaft TM 1 by operation of the fourth clutch C 4 .

However, the input through the fifth rotation shaft TM 5 does not affect on the shifting, and the input through the first rotation shaft TM 1 affects on the shifting. In addition, the second rotation shaft TM 2 is stopped by operation of the first brake B 1 . Therefore, the rotation elements of the first compound planetary gear set CPG 1 form the fifth speed line T 5 and the fifth speed is output through the third rotation shaft TM 3 .

In a state that the fifth speed is input to the third rotation shaft TM 3 , the sixth rotation shaft TM 6 is operated as the fixed element by operation of the third brake B 3 . Therefore, the rotation elements of the second compound planetary gear set CPG 2 form a revere shift line SR.

The reverse shift line SR crosses the vertical line of the seventh rotation shaft TM 7 that is the output element, and REV is output.

According to various embodiments of the present invention, eleven forward speeds and one reverse speed may be achieved by combining four planetary gear sets PG 1 , PG 2 , PG 3 , and PG 4 into two compound planetary gear sets CPG 1 and CPG 2 and controlling four clutches C 1 , C 2 , C 3 , and C 4 and three brakes B 1 , B 2 , and B 3 .

That is, the first compound planetary gear set CPG 1 firstly changes the rotation speed of the input shaft IS into two reduced speed, speed of 0, speed of 1 the same as the input shaft IS, one increased speed, and one inverse speed, and the second compound planetary gear set CPG 2 secondary changes the output of the first compound planetary gear set CPG 1 and the rotation speed of the input shaft IS into eleven forward speeds and one reverse speed.

The planetary gear train according to various embodiments of the present invention may improve power delivery efficiency and fuel economy by achieving multiple-speeds of the automatic transmission.

Since at least three friction members are operated at each speed, the number of the friction members that are not operated can be reduced. Therefore, drag loss may be reduced and power delivery efficiency and fuel economy may be further improved.

In addition, all the four planetary gear sets PG 1 , PG 2 , PG 3 , and PG 4 are not involved in each speed, but one to four planetary gear sets are involved in each speed in the planetary gear train according to various embodiments of the present invention.

That is, the second and third planetary gear sets PG 2 and PG 3 are involved in the first forward speed, the first, second, and third planetary gear sets PG 1 , PG 2 , and PG 3 are involved in the second forward speed, the third planetary gear set PG 3 is involved in the third forward speed, and the first and third planetary gear sets PG 1 and PG 3 are involved in the fourth forward speed.

In addition, the third and fourth planetary gear sets PG 3 and PG 4 are involved in the fifth forward speed, the first and fourth planetary gear sets PG 1 and PG 4 are involved in the sixth forward speed, and the first, second, third and fourth planetary gear sets PG 1 , PG 2 , PG 3 and PG 4 are involved in the seventh forward speed.

In addition, the first, second, and fourth planetary gear sets PG 1 , PG 2 , and PG 4 are involved in the eighth forward speed, the second and fourth planetary gear sets PG 2 and PG 4 are involved in the ninth forward speed, the fourth planetary gear set PG 4 is involved in the tenth forward speed, and the first and fourth planetary gear sets PG 1 and PG 4 are involved in the eleventh forward speed.

In addition, the first and third planetary gear sets PG 1 and PG 3 are involved in the reverse speed.

Since the number of the planetary gear sets involved in each speed is minimized, power loss may be also minimized.

For convenience in explanation and accurate definition in the appended claims, the terms upper or lower, front or rear, and etc. are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.