Planetary gear train of automatic transmission for vehicles

The present application claims priority of Korean Patent Application Number 10-2011-0037384 filed in the Korean Intellectual Property Office on Apr. 21, 2011, the entire contents of which application are incorporated herein for all purposes by this reference.

1. Field of Invention

The present invention relates to an automatic transmission for vehicles. More particularly, the present invention relates to a planetary gear train of an automatic transmission for vehicles which improves power delivery performance and reduces fuel consumption.

2. Description of Related Art

Typically, a planetary gear train is realized by combining a plurality of planetary gear sets, and the planetary gear train including the plurality of planetary gear sets receives torque from a torque converter and changes and transmits 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, the planetary gear train 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 rotation elements (i.e., sun gear, planet carrier, and ring gear).

In addition, the planetary gear train has different features such durability, power delivery efficiency, and size depending 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 ten-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 are directed to provide a planetary gear train of an automatic transmission for vehicles having advantages of improving power delivery performance by combining a plurality of planetary gear sets with a plurality of friction members so as to firstly shift torque of an input shaft to two reduced speed ratio, a direct-coupling speed ratio, and an increased speed ratio, and to achieve final shift-speeds including at least ten forward speeds and four reverse speeds by using firstly shifted torque and the torque of the input shaft input through other path.

Exemplary planetary gear trains of an automatic transmission for vehicles according to the present invention may include: an input shaft configured to receive an engine torque; an output shaft configured to output a shifted torque; a first compound planetary gear set including a first simple planetary gear set having a first sun gear, a first planet carrier, and a first ring gear as rotation elements thereof and a second simple planetary gear set having a second sun gear, a second planet carrier, and a second ring gear as rotation elements thereof; a second compound planetary gear set including a third simple planetary gear set having a third sun gear, a third planet carrier, and a third ring gear as rotation elements thereof and a fourth simple planetary gear set having a fourth sun gear, a fourth planet carrier, and a fourth ring gear as rotation elements thereof; seven rotational shafts, connecting at least two rotation elements among the rotation elements of the first and second compound planetary gear sets or connected to one rotation element; and seven friction members including three clutches interposed between a rotational shaft selected among the rotational shafts and the input shaft so as to control the torque and four brakes selectively connecting a rotational shaft selected among the rotational shafts to a transmission housing.

Exemplary first compound planetary gear set according to the present invention may include four rotational shafts among the seven rotational shafts and may be adapted to receive the torque of the input shaft through two paths and to output four speed ratios. The four speed ratios may include two reduced speed ratios, a direct-coupling speed ratio, and an increased speed ratio.

In exemplary planetary gear trains according to the present invention, the first and second simple planetary gear sets of the first compound planetary gear set may be single pinion planetary gear sets. The first planet carrier may be directly connected to the second ring gear and the first ring gear may be directly connected to the second planet carrier in the first compound planetary gear set.

Exemplary second compound planetary gear set according to the present invention may be connected to one rotational shaft included in the first compound planetary gear set, may include three other rotational shafts not connected to the first compound planetary gear set among the seven rotational shafts, and be adapted to receive the torque input from the first compound planetary gear set and the torque of the input shaft through one path and to output ten forward speeds and four reverse speeds.

In exemplary planetary gear trains according to the present invention, the third and fourth simple planetary gear sets of the second compound planetary gear set may be single pinion planetary gear sets. The third planet carrier may be directly connected to the fourth ring gear, the third ring gear may be directly connected to the fourth planet carrier, and the third sun gear may be directly connected to the second planet carrier in the second compound planetary gear set.

In addition, in exemplary planetary gear trains according to the present invention, the seven rotational shafts may include: a first rotational shaft including the first sun gear and selectively connected to the transmission housing through a first friction member; a second rotational shaft including the first planet carrier and the second ring gear, selectively connected to the input shaft through a second friction member, and selectively connected to the transmission housing through a third friction member; a third rotational shaft including the first ring gear, the second planet carrier, and the third sun gear; a fourth rotational shaft including the second sun gear and selectively connected to the input shaft through a fourth friction member; a fifth rotational shaft including the third planet carrier and the fourth ring gear, selectively connected to the input shaft through a fifth friction member, and selectively connected to the transmission housing through a sixth friction member; a sixth rotational shaft including the third ring gear and the fourth planet carrier and connected the output shaft; and a seventh rotational shaft including the fourth sun gear and selectively connected to the transmission housing through a seventh friction member.

Moreover, in exemplary planetary gear trains according to the present invention, the friction members may include: a first clutch interposed between the input shaft and the fourth rotational shaft; a second clutch interposed between the input shaft and the second rotational shaft; a third clutch interposed between the input shaft and the fifth rotational shaft; a first brake interposed between the second rotational shaft and the transmission housing; a second brake interposed between the first rotational shaft and the transmission housing; a third brake interposed between the fifth rotational shaft and the transmission housing; and a fourth brake interposed between the seventh rotational shaft and the transmission housing.

Exemplary planetary gear trains according to the present invention may further include a one-way clutch disposed in parallel with the first brake.

Furthermore, in exemplary planetary gear trains according to the present invention, the first clutch and the first and fourth brakes are operated at a first forward speed, the first clutch and the second and fourth brakes are operated at a second forward speed, the first and second clutches and the fourth brake are operated at a third forward speed, the second clutch and the second and fourth brakes are operated at a fourth forward speed, the third clutch and the second and fourth brakes are operated at a fifth forward speed, the second and third clutches and the second brake are operated at a sixth forward speed, the first, second, and third clutches are operated at a seventh forward speed, the first and third clutches and the second brake are operate at an eighth forward speed, the first and third clutches and the first brake are operated at a ninth forward speed, the third clutch and the first and second brakes are operated at a tenth forward speed, the first clutch and the first and third brakes are operated at a first reverse speed, the first clutch and the second and third brakes are operated at a second reverse speed, the first and second clutches and the third brake are operated at a third reverse speed, and the second clutch and the second and third brakes are operated at a fourth 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 shows connections in an exemplary planetary gear train according to the present invention.

FIG. 3 is an operational chart of friction members at each shift-speed applied to an exemplary planetary gear train according to the present invention.

FIG. 4 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 present exemplary embodiment will be omitted, and the same constituent elements are denoted by the same reference numerals in this specification. In the detailed description, numerals are used for distinguishing constituent elements having the same terms, and have no specific meanings or indicate any orders.

Referring to FIG. 1 , exemplary planetary gear trains according to the present invention may include first, second, third, and fourth simple planetary gear sets PG 1 , PG 2 , PG 3 , and PG 4 disposed on the same axis, clutch means including three clutches C 1 , C 2 , and C 3 , and brake means including four brakes B 1 , B 2 , B 3 , and B 4 .

A rotation speed 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 is output through the output shaft OS.

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

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 delivers driving torque so as to run driving wheels through a differential apparatus.

The first simple 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 , and a first ring gear R 1 as rotation elements thereof.

Herein, the first planet carrier PC 1 rotatably supports a plurality of first pinion gears P 1 engaged to the first sun gear S 1 and the first ring gear R 1 .

The second simple planetary gear set PG 2 is a single pinion planetary gear set, and includes a second sun gear S 2 , a second planet carrier PC 2 , and a second ring gear R 2 as rotation elements thereof.

Herein, the second planet carrier PC 2 rotatably supports a plurality of second pinion gears P 2 engaged to the second sun gear S 2 and the second ring gear R 2 .

The third simple 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 , and a third ring gear R 3 as rotation elements thereof.

Herein, the third planet carrier PC 3 rotatably supports a plurality of third pinion gears P 3 engaged to the third sun gear S 3 and the third ring gear R 3 .

The fourth simple 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 , and a fourth ring gear R 4 as rotation elements thereof.

Herein, the fourth planet carrier PC 4 rotatably supports a plurality of fourth pinion gears P 4 engaged to the fourth sun gear S 4 and the fourth ring gear R 4 .

In addition, the first, second, third, and fourth simple planetary gear sets PG 1 , PG 2 , PG 3 , and PG 4 form two compound planetary gear sets CPG 1 and CPG 2 , change the torque transmitted from the input shaft into ten forward speeds, and output the ten forward speeds.

The first compound planetary gear set CPG 1 includes the first and second simple planetary gear sets PG 1 and PG 2 , and the second compound planetary gear set CPG 2 includes the third and fourth simple planetary gear sets PG 3 and PG 4 .

Referring to FIG. 1 and FIG. 2 , the first planet carrier PC 1 is directly connected to the second ring gear R 2 and the first ring gear R 1 is directly connected to the second planet carrier PC 2 in the first compound planetary gear set CPG 1 .

In addition, the third planet carrier PC 3 is directly connected to the fourth ring gear R 4 , the third ring gear R 3 is directly connected to the fourth planet carrier PC 4 , and the third sun gear S 3 is directly connected to the second planet carrier PC 2 in the second compound planetary gear set CPG 2 .

Accordingly, the planetary gear train according to various embodiments includes seven rotational shafts TM 1 -TM 7 .

The first rotational shaft TM 1 includes the first sun gear S 1 and is selectively connected to a transmission housing H.

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

The third rotational shaft TM 3 includes the first ring gear R 1 , the second planet carrier PC 2 , and the third sun gear S 3 .

The fourth rotational shaft TM 4 includes the second sun gear S 2 and is selectively connected to the input shaft IS.

The fifth rotational shaft TM 5 includes the third planet carrier PC 3 and the fourth ring gear R 4 , is selectively connected to the input shaft IS, and is selectively connected to the transmission housing H.

The sixth rotational shaft TM 6 includes the third ring gear R 3 and the fourth planet carrier PC 4 and is directly connected to the output shaft OS.

The seventh rotational shaft TM 7 includes the fourth sun gear S 4 and is selectively connected to the transmission housing H.

In addition, the fourth, second, and fifth rotational shafts TM 4 , TM 2 , and TM 5 among the rotational shafts TM 1 -TM 7 selectively connected to the input shaft IS and operated as a selective input member are connected to the input shaft IS respectively through first, second, and third clutches C 1 , C 2 , and C 3 .

In addition, the second, first, fifth, and seventh rotational shafts TM 2 , TM 1 , TM 5 , and TM 7 among the rotational shafts TM 1 -TM 7 selectively connected to the transmission housing H and operated as a selective fixed member are connected to the transmission housing H through first, second, third, and fourth brakes B 1 , B 2 , B 3 , and B 4 .

That is, the first clutch C 1 is interposed between the input shaft IS and the fourth rotational shaft TM 4 so as to operate the fourth rotational shaft TM 4 as the selective input element.

The second clutch C 2 is interposed between the input shaft IS and the second rotational shaft TM 2 so as to operate the second rotational shaft TM 2 as the selective input element.

The third clutch C 3 is interposed between the input shaft IS and the fifth rotational shaft TM 5 so as to operate the fifth rotational shaft TM 5 as the selective input element.

The first brake B 1 is interposed between the second rotational shaft TM 2 and the transmission housing H so as to operate the second rotational shaft TM 2 as the selective fixed element.

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

The second brake B 2 is interposed between the first rotational shaft TM 1 and the transmission housing H so as to operate the first rotational shaft TM 1 as the selective fixed element.

The third brake B 3 is interposed between the fifth rotational shaft TM 5 and the transmission housing H so as to operate the fifth rotational shaft TM 5 as the selective fixed element.

The fourth brake B 4 is interposed between the seventh rotational shaft TM 7 and the transmission housing H so as to operate the seventh rotational shaft TM 7 as the selective fixed element.

The first and second clutches C 1 and C 2 and the first and second brakes B 1 and B 2 are applied to the first compound planetary gear set CPG 1 , and the torque input through the first and second clutches C 1 and C 2 is changed into four speed ratios according to operations of the first and second brakes B 1 and B 2 .

At this time, the four speed ratios include two reduced speed ratios, one direct-coupling speed ratio, and one increased speed ratio.

In addition, the third clutch C 3 and the third and fourth brakes B 3 and B 4 are applied to the second compound planetary gear set CPG 2 , and the torque directly input from the input shaft IS through the third clutch C 3 and the torque changed into four speed ratios and input from the first compound planetary gear set CPG 2 are changed into ten forward speeds and four reverse speeds by operations of the third and fourth brakes B 3 and 84 .

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

The numbers of planetary gear sets, forward speeds, reverse speeds, rotational shafts, speed ratios, clutches, brakes and etc. described in the application are exemplary. One skilled in the art would appreciate that the present invention is not limited to these exemplary numbers, and specific number for each group may vary.

FIG. 3 is an operational chart of friction members at each shift-speed applied to an exemplary planetary gear train according to the present invention. Referring to FIG. 3 , seven friction members, including three clutches C 1 , C 2 , and C 3 and four brakes B 1 , B 2 , B 3 , and B 4 , are selectively operated at each shift-speed. According to various embodiments, three friction members are operated at each shift-speed.

At a first forward speed, the first clutch C 1 and the first and fourth brakes B 1 and B 4 are operated.

The first clutch C 1 and the second and fourth brakes B 2 and B 4 are operated at a second forward speed, and the first and second clutches C 1 and C 2 and the fourth brake B 4 are operated at a third forward speed.

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

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

The first and third clutches C 1 and C 3 and the second brake B 2 are operated at an eighth forward speed, and the first and third clutches C 1 and C 3 and the first brake B 1 are operated at a ninth forward speed.

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

The first clutch C 1 and the second and third brakes B 2 and B 3 are operated at a second reverse speed, and the first and second clutches C 1 and C 2 and the third brake B 3 are operated at a third reverse speed. In addition, the second clutch C 2 and the second and third brakes B 2 and B 3 are operated at a fourth reverse speed.

It is explained that the first clutch C 1 and the first and fourth brakes B 1 and B 4 are operated at the first forward speed, but the one-way clutch F 1 instead of the first brake B 1 is operated at a normal driving.

FIG. 4 is a lever diagram for an exemplary planetary gear train according to the present invention and shows shifting processes of the exemplary planetary gear train according to the present invention.

Referring to FIG. 4 , a lower horizontal line represents a rotation speed is “0”, and an upper horizontal line represents a rotation speed is “1.0”, that is, the rotation speed thereof is the same as that of the input shaft IS.

Four vertical lines of the first compound planetary gear set CPG 1 sequentially represent the first, second, third, and fourth rotational shafts TM 1 , TM 2 , TM 3 , and TM 4 from the left to the right.

Herein, distances between the first, second, third, and fourth rotational shafts TM 1 , TM 2 , TM 3 , and TM 4 are set according to gear ratios (teeth number of the sun gear/teeth number of the ring gear) of the first and second simple planetary gear sets PG 1 and PG 2 .

Four vertical lines of the second compound planetary gear set CPG 2 sequentially represent the third, fifth, sixth, and seventh rotational shafts TM 3 , TM 5 , TM 6 , and TM 7 from the left to the right.

Herein, distances between the third, fifth, sixth, and seventh rotational shafts TM 3 , TM 5 , TM 6 , and TM 7 are set according to gear ratios (teeth number of the sun gear/teeth number of the ring gear) of the third and fourth simple planetary gear sets PG 3 and PG 4 .

The reason why the third rotational shaft TM 3 is included in both the first compound planetary gear set CPG 1 and the second compound planetary gear set CPG 2 is that the third rotational shaft TM 3 is integrally formed with the first ring gear R 1 , the second planet carrier PC 2 , and the third sun gear S 3 .

Referring to FIG. 3 and FIG. 4 , shifting processes for each shift-speed in the planetary gear train according to various embodiments will be described.

First Forward Speed

Referring to FIG. 3 , the first clutch C 1 and the first and fourth brakes B 1 and B 4 are operated at the first forward speed.

As shown in FIG. 4 , in a state that the rotation speed of the input shaft IS is input to the fourth rotational shaft TM 4 by operation of the first clutch C 1 , the second rotational shaft TM 2 is operated as the fixed element by operation of the first brake B 1 in the first compound planetary gear set CPG 1 .

Accordingly, the first compound planetary gear set CPG 1 forms a first reduced speed line T 1 and a first reduced speed is output through the third rotational shaft TM 3 .

In addition, in a state that the rotation speed of the third rotational shaft TM 3 is input to the second compound planetary gear set CPG 2 , the seventh rotational shaft TM 7 is operated as the fixed element by operation of the fourth brake B 4 such that a first shift line SP 1 is formed.

The first shift line SP 1 crosses a vertical line of the sixth rotational shaft TM 6 that is the output element such that D 1 is output.

Second Forward Speed

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

In a state that the rotation speed of the input shaft IS is input to the fourth rotational shaft TM 4 by operation of the first clutch C 1 , the first rotational shaft TM 1 is operated as the fixed element by operation of the second brake B 2 in the first compound planetary gear set CPG 1 .

Accordingly, the first compound planetary gear set CPG 1 forms a second reduced speed line T 2 and a second reduced speed is output through the third rotational shaft TM 3 .

In addition, in a state that the rotation speed of the third rotational shaft TM 3 is input to the second compound planetary gear set CPG 2 , the seventh rotational shaft TM 7 is operated as the fixed element by operation of the fourth brake B 4 such that a second shift line SP 2 is formed.

The second shift line SP 2 crosses the vertical line of the sixth rotational shaft TM 6 that is the output element such that D 2 is output.

Third Forward Speed

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

The rotation speed of the input shaft IS is simultaneously input to the second and fourth rotational shafts TM 2 and TM 4 by operations of the first and second clutches C 1 and C 2 in the first compound planetary gear set CPG 1 , and the first compound planetary gear set CPG 1 becomes a direct-coupling state. Therefore, the first compound planetary gear set CPG 1 forms a direct-coupling speed line T 3 and the rotation speed of the input shaft IS is output through the third rotational shaft TM 3 .

In addition, in a state that the rotation speed of the third rotational shaft TM 3 is input to the second compound planetary gear set CPG 2 , the seventh rotational shaft TM 7 is operated as the fixed element by operation of the fourth brake B 4 such that a third shift line SP 3 is formed.

The third shift line SP 3 crosses the vertical line of the sixth rotational shaft TM 6 that is the output element such that D 3 is output.

Fourth Forward Speed

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

In a state that the rotation speed of the input shaft IS is input to the second rotational shaft TM 2 by operation of the second clutch C 2 , the first rotational shaft TM 1 is operated as the fixed element by operation of the second brake B 2 in the first compound planetary gear set CPG 1 .

Accordingly, the first compound planetary gear set CPG 1 forms an increased speed line T 4 and an increased speed is output through the third rotational shaft TM 3 .

In addition, in a state that the rotation speed of the third rotational shaft TM 3 is input to the second compound planetary gear set CPG 2 , the seventh rotational shaft TM 7 is operated as the fixed element by operation of the fourth brake B 4 such that a fourth shift line SP 4 is formed.

The fourth shift line SP 4 crosses the vertical line of the sixth rotational shaft TM 6 that is the output element such that D 4 is output.

Fifth Forward Speed

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

Since the first and second clutches C 1 and C 2 are not operated, the first compound planetary gear set CPG 1 does not influence on the shifting.

In a state that the rotation speed of the input shaft IS is input to the second compound planetary gear set CPG 2 through the fifth rotational shaft TM 5 by operation of the third clutch C 3 , the seventh rotational shaft TM 7 is operated as the fixed element by operation of the fourth brake B 4 such that a fifth shift line SP 5 is formed.

The fifth shift line SP 5 crosses the vertical line of the sixth rotational shaft TM 6 that is the output element such that D 5 is output.

Sixth Forward Speed

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

In a state that the rotation speed of the input shaft IS is input to the second rotational shaft TM 2 by operation of the second clutch C 2 , the first rotational shaft TM 1 is operated as the fixed element by operation of the second brake B 2 in the first compound planetary gear set CPG 1 .

Accordingly, the first compound planetary gear set CPG 1 forms an increased speed line T 4 and an increased speed is output through the third rotational shaft TM 3 .

In addition, in a state that the rotation speed of the third rotational shaft TM 3 is input to the second compound planetary gear set CPG 2 , the rotation speed of the input shaft IS is input to the fifth rotational shaft TM 5 by operation of the third clutch C 3 such that a sixth shift line SP 6 is formed.

The sixth shift line SP 6 crosses the vertical line of the sixth rotational shaft TM 6 that is the output element such that D 6 is output.

Seventh Forward Speed

The second brake B 2 that was operated at the sixth forward speed is released and the first clutch C 1 is operated at the seventh forward speed.

The rotation speed of the input shaft IS is simultaneously input to the second and fourth rotational shafts TM 2 and TM 4 by operations of the first and second clutches C 1 and C 2 in the first compound planetary gear set CPG 1 , and the first compound planetary gear set CPG 1 becomes a direct-coupling state.

Therefore, the first compound planetary gear set CPG 1 forms a direct-coupling speed line T 3 and the rotation speed of the input shaft IS is output through the third rotational shaft TM 3 .

In addition, in a state that the rotation speed of the third rotational shaft TM 3 is input to the second compound planetary gear set CPG 2 , the rotation speed of the input shaft IS is input to the fifth rotational shaft TM 5 by operation of the third clutch C 3 such that the second compound planetary gear set CPG 2 becomes the direct-coupling state and a seventh shift line SP 7 is formed.

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

Eighth Forward Speed

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

In a state that the rotation speed of the input shaft IS is input to the fourth rotational shaft TM 4 by operation of the first clutch C 1 , the first rotational shaft TM 1 is operated as the fixed element by operation of the second brake B 2 in the first compound planetary gear set CPG 1 .

Accordingly, the first compound planetary gear set CPG 1 forms a second reduced speed line T 2 and a second reduced speed is output through the third rotational shaft TM 3 .

In addition, in a state that the rotation speed of the third rotational shaft TM 3 is input to the second compound planetary gear set CPG 2 , the rotation speed of the input shaft IS is input to the fifth rotational shaft TM 5 by operation of the third clutch C 3 such that an eighth shift line SP 8 is formed.

The eighth shift line SP 8 crosses the vertical line of the sixth rotational shaft TM 6 that is the output element such that D 8 is output.

Ninth Forward Speed

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

In a state that the rotation speed of the input shaft IS is input to the fourth rotational shaft TM 4 by operation of the first clutch C 1 , the second rotational shaft TM 2 is operated as the fixed element by operation of the first brake B 1 in the first compound planetary gear set CPG 1 .

Accordingly, the first compound planetary gear set CPG 1 forms a first reduced speed line T 1 and a first reduced speed is output through the third rotational shaft TM 3 .

In addition, in a state that the rotation speed of the third rotational shaft TM 3 is input to the second compound planetary gear set CPG 2 , the rotation speed of the input shaft IS is input to the fifth rotational shaft TM 5 by operation of the third clutch C 3 such that a ninth shift line SP 9 is formed.

The ninth shift line SP 9 crosses the vertical line of the sixth rotational shaft TM 6 that is the output element such that D 9 is output.

Tenth Forward Speed

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

The first compound planetary gear set CPG 1 is stopped because the first and second brakes B 1 and B 2 are operated in a state that the first and second clutches C 1 and C 2 are not operated.

In a state that the rotation speed of the input shaft IS is input to the second compound planetary gear set CPG 2 through the fifth rotational shaft TM 5 by operation of the third clutch C 3 , the third rotational shaft TM 3 is operated as the fixed element by the stopping state of the first compound planetary gear set CPG 1 such that a tenth shift line SP 10 is formed.

The tenth shift line SP 10 crosses the vertical line of the sixth rotational shaft TM 6 that is the output element such that D 10 is output.

First Reverse Speed

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

In a state that the rotation speed of the input shaft IS is input to the fourth rotational shaft TM 4 by operation of the first clutch C 1 , the second rotational shaft TM 2 is operated as the fixed element by operation of the first brake B 1 in the first compound planetary gear set CPG 1 .

Accordingly, the first compound planetary gear set CPG 1 forms a first reduced speed line T 1 and a first reduced speed is output through the third rotational shaft TM 3 .

In addition, in a state that the rotation speed of the third rotational shaft TM 3 is input to the second compound planetary gear set CPG 2 , the fifth rotational shaft TM 5 is operated as the fixed element by operation of the third brake B 3 such that a first reverse shift line SR 1 is formed.

The first reverse shift line SRI crosses the vertical line of the sixth rotational shaft TM 6 that is the output element such that REV 1 is output.

Second Reverse Speed

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

In a state that the rotation speed of the input shaft IS is input to the fourth rotational shaft TM 4 by operation of the first clutch C 1 , the first rotational shaft TM 1 is operated as the fixed element by operation of the second brake B 2 in the first compound planetary gear set CPG 1 .

Accordingly, the first compound planetary gear set CPG 1 forms a second reduced speed line T 2 and a second reduced speed is output through the third rotational shaft TM 3 .

In addition, in a state that the rotation speed of the third rotational shaft TM 3 is input to the second compound planetary gear set CPG 2 , the fifth rotational shaft TM 5 is operated as the fixed element by operation of the third brake B 3 such that a second reverse shift line SR 2 is formed.

The second reverse shift line SR 2 crosses the vertical line of the sixth rotational shaft TM 6 that is the output element such that a REV 2 is output.

Third Reverse Speed

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

The rotation speed of the input shaft IS is simultaneously input to the second and fourth rotational shafts TM 2 and TM 4 by operations of the first and second clutches C 1 and C 2 in the first compound planetary gear set CPG 1 , and the first compound planetary gear set CPG 1 becomes a direct-coupling state. Therefore, the first compound planetary gear set CPG 1 forms a direct-coupling speed line T 3 and the rotation speed of the input shaft IS is output through the third rotational shaft TM 3 .

In addition, in a state that the rotation speed of the third rotational shaft TM 3 is input to the second compound planetary gear set CPG 2 , the fifth rotational shaft TM 5 is operated as the fixed element by operation of the third brake B 3 such that a third reverse shift line SR 3 is formed.

The third reverse shift line SR 3 crosses the vertical line of the sixth rotational shaft TM 6 that is the output element such that a REV 3 is output.

Fourth Reverse Speed

In a state that the rotation speed of the input shaft IS is input to the second rotational shaft TM 2 by operation of the second clutch C 2 , the first rotational shaft TM 1 is operated as the fixed element by operation of the second brake B 2 in the first compound planetary gear set CPG 1 .

Accordingly, the first compound planetary gear set CPG 1 forms an increased speed line T 4 and an increased speed is output through the third rotational shaft TM 3 .

In addition, in a state that the rotation speed of the third rotational shaft TM 3 is input to the second compound planetary gear set CPG 2 , the fifth rotational shaft TM 5 is operated as the fixed element by operation of the third brake B 3 such that a fourth reverse shift line SR 4 is formed.

The fourth reverse shift line SR 4 crosses the vertical line of the sixth rotational shaft TM 6 that is the output element such that a REV 4 is output.

Since four simple planetary gear sets is combined with seven friction members and three friction members are operated at each shift-speed according various embodiments of the present invention, ten forward speeds are achieved. Therefore, power delivery performance and fuel economy may be improved.

In addition, since four reverse speeds are achieved, reverse speed performance may be improved.

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.