Planetary gear train of automatic transmission for vehicles

This application claims priority to and the benefit of Korean Patent Application No. 10-2017-0052120, filed on Apr. 24, 2017, which is incorporated herein by reference in its entirety.

The present disclosure relates to an automatic transmission for a vehicle.

The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

Recently, increases of oil price has triggered more competition for enhancing fuel efficiency of a vehicle.

In this regard, research on an automatic transmission has been conducted as well to provide better drivability and improve fuel efficiency by achieving more shift stages.

In order to achieve more shift stages for an automatic transmission, the number of parts is typically increased, which may negatively affect installability, production cost, weight and/or power flow efficiency.

As an effort to increase fuel efficiency of an automatic transmission by more shift stages with reduced number of parts, an eight-speed automatic transmission has been recently introduced, and a planetary gear train for an automatic transmission enabling more shift stages has been developed.

An automatic transmission of eight or more shift-stages typically includes three to four planetary gear sets and five to six control elements (frictional elements), and may easily become lengthy, thereby deteriorating installability.

In this regard, disposing planetary gear sets in parallel or employing dog clutches instead of wet-type control elements is sometimes attempted. However, such an arrangement may not be widely applicable, and using dog clutches may easily deteriorate shift-feel.

In addition, we have discovered that a recent eight-speed automatic transmission typically shows a gear ratio span in a level of 6.5 to 7.5, and improvement for better fuel consumption is limited.

The present disclosure provides a planetary gear train of an automatic transmission for a vehicle having advantages of realizing at least eight forward speeds and at least one reverse speed by a combination of four planetary gear sets, two external gears and five control elements, thereby providing improvement of power delivery performance and fuel consumption as well as improving installability by reducing a total length of the transmission.

In addition, a wide available range of gear teeth of transfer gears enables easily obtaining optimum gear ratios for respective vehicles, thereby improving power delivery performance and fuel consumption.

A planetary gear train of an automatic transmission for a vehicle according to an exemplary form of the present disclosure may include: a first planetary gear set having first, second, and third rotational elements; a second planetary gear set having fourth, fifth, and sixth rotational elements; a third planetary gear set having seventh, eighth, and ninth rotational elements; a fourth planetary gear set having tenth, eleventh, and twelfth rotational elements; an input shaft mounted with the first, second, and third planetary gear sets at an external circumference of the input shaft; and an output shaft disposed in parallel with the input shaft and mounted with the fourth planetary gear set on external circumference of the output shaft; a first shaft fixedly connected with the first rotational element; a second shaft fixedly connected with the second rotational element and the fifth rotational element; a third shaft fixedly connected with the third rotational element and the input shaft; a fourth shaft fixedly connected with the fourth rotational element and the seventh rotational element; a fifth shaft fixedly connected with the sixth rotational element; a sixth shaft fixedly connected with the eighth rotational element; a seventh shaft fixedly connected with the ninth rotational element; an eighth shaft fixedly connected with the tenth rotational element and externally engaged with the first shaft; a ninth shaft fixedly connected with the eleventh rotational element and the output shaft; a tenth shaft fixedly connected with the twelfth rotational element and externally engaged with the sixth shaft; and two transfer gears externally gear-meshed with the first and sixth shafts, respectively.

The fourth shaft may selectively act as a fixed element, the fifth shaft may be selectively connected with the first shaft, the sixth shaft may be selectively connected with the fifth shaft, and the seventh shaft may selectively act as a fixed element.

The first planetary gear set may include a first sun gear as the first rotational element, a first ring gear as the second rotational element, and a first planet carrier as the third rotational element; the second planetary gear set comprises a second sun gear as the fourth rotational element, a second planet carrier as the fifth rotational element, and a second ring gear as the sixth rotational element; the third planetary gear set comprises a third sun gear as the seventh rotational element, a third planet carrier as the eighth rotational element, and a third ring gear as the ninth rotational element; and the fourth planetary gear set comprises a fourth sun gear as the tenth rotational element, a fourth planet carrier as the eleventh rotational element, and a fourth ring gear as the twelfth rotational element.

The first, second, third planetary gear sets may be arranged on the input shaft in the order of the first, second, and third planetary gear sets.

The two transfer gears may include a first transfer gear arranged between the first shaft and the eighth shaft; and a second transfer gear arranged between the sixth shaft and the tenth shaft.

At least two rotational elements among the first, the second, and the third rotational element of the first planetary gear set may be selectively connected to each other such that all rotational elements of the first planetary gear set may integrally rotate.

The planetary gear train may further include a first clutch arranged between the first shaft and the third shaft; a second clutch arranged between the first shaft and the fifth shaft; a third clutch arranged between the fifth shaft and the sixth shaft; a first brake arranged between the fourth shaft and a transmission housing; and a second brake arranged between the seventh shaft and the transmission housing.

The planetary gear train may further include a first clutch arranged between the first shaft and the second shaft; a second clutch arranged between the first shaft and the fifth shaft; a third clutch arranged between the fifth shaft and the sixth shaft; a first brake arranged between the fourth shaft and the transmission housing; and a second brake arranged between the seventh shaft and the transmission housing.

The planetary gear train may further include a second clutch arranged between the first shaft the fifth shaft; a third clutch arranged between the fifth shaft and the sixth shaft; a first brake arranged between the fourth shaft and the transmission housing; and a second brake arranged between the seventh shaft and the transmission housing.

According to a planetary gear train according to an exemplary form of the present disclosure, planetary gear sets are dividedly arranged on input and output shafts disposed in parallel, thereby reducing a length and improving installability.

According to a planetary gear train according to an exemplary form of the present disclosure, at least eight forward speeds and at least one reverse speed may be realized by employing two transfer gears in addition to a combination of planetary gear sets, thereby providing a wide range of varying gear teeth so as to easily achieve desired gear ratio and to easily comply with desired performance for respective vehicles.

In addition, according to a planetary gear train according to an exemplary form of the present disclosure, a gear ratio span of more than 8.8 may be achieved while realizing eight forward speeds and one reverse speed, thereby increasing an engine driving efficiency.

In addition, the linearity of step ratios of shift stages is secured while multi-staging the shift stage with high efficiency, thereby making it possible to improve drivability such as acceleration before and after a shift, an engine speed rhythmic sense, and the like.

In addition, five control elements are applied to the planetary gear train according to an exemplary form of the present disclosure, thereby making it possible to reduce material cost due to reduction of constituent components, and reduce non-controlled control elements so as to reduce a drag torque, and improve a power transmission efficiency so as to reduce fuel consumption.

Further, effects that can be obtained or expected from exemplary forms of the present disclosure are directly or suggestively described in the following detailed description. That is, various effects expected from exemplary forms of the present disclosure will be described in the following detailed description.

Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which:

FIG. 1 is a schematic diagram of a planetary gear train according to a first exemplary form of the present disclosure;

FIG. 2 is an operation chart for respective control elements at respective shift-stages in a planetary gear train according to an exemplary form of the present disclosure;

FIG. 3 is a schematic diagram of a planetary gear train according to a second exemplary form of the present disclosure; and

FIG. 4 is a schematic diagram of a planetary gear train according to a third exemplary form of the present disclosure.

The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

The present disclosure will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary forms of the present disclosure are shown. As those skilled in the art would realize, the described forms may be modified in various different ways, all without departing from the spirit or scope of the present disclosure.

The drawings and description are to be regarded as illustrative in nature and not restrictive, and like reference numerals designate like elements throughout the specification.

In the following description, dividing names of components into first, second and the like is to divide the names because the names of the components are the same as each other and an order thereof is not particularly limited.

Further, as used herein, description of elements being “fixedly” connected or interconnected includes elements that are directly connected, i.e. one element directly connected to another element for rotation therewith.

FIG. 1 is a schematic diagram of a planetary gear train according to a first exemplary form of the present disclosure.

Referring to FIG. 1 , a planetary gear train according to a first exemplary form of the present disclosure includes: an input shaft IS; an output shaft OS; first, second, third, and fourth planetary gear sets PG 1 , PG 2 , PG 3 , and PG 4 ; two transfer gears TF 1 and TF 2 ; and control elements including three clutches C 1 , C 2 , and C 3 and two brakes B 1 , and B 2 .

The input shaft IS is an input member and the torque from a crankshaft of an engine is input into the input shaft IS, after being torque-converted through a torque converter.

The output shaft OS is an output member, which is arranged in parallel with the input shaft IS, outputs a shifted driving torque to a drive shaft through a differential apparatus.

The first, second, and third planetary gear sets PG 1 , PG 2 , and PG 3 are arranged at external circumference of the input shaft IS and form a main shifting portion. The first, second, third planetary gear sets PG 1 , PG 2 , and PG 3 are arranged on the input shaft IS in the order of first, second, and third planetary gear sets PG 1 , PG 2 , and PG 3 .

The fourth planetary gear set PG 4 is arranged at external circumference of the output shaft OS disposed in parallel with the input shaft IS and forms an auxiliary shifting portion.

The first planetary gear set PG 1 is a double pinion planetary gear set, and includes a first sun gear S 1 , a first ring gear R 1 that is externally engaged with a first pinion P 1 externally engaged with the first sun gear S 1 , and a first planet carrier PC 1 supporting the first pinion P 1 . The first sun gear S 1 acts as a first rotational element N 1 , the first ring gear R 1 acts as a second rotational element N 2 , and first planet carrier PC 1 acts as a third rotational element N 3 .

The second 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 that supports the second pinion P 2 externally engaged with the second sun gear S 2 , and a second ring gear R 2 that is internally engaged with the second pinion P 2 . The second sun gear S 2 acts as a fourth rotational element N 4 , the second planet carrier PC 2 acts as a fifth rotational element N 5 , and the second ring gear R 2 acts as a sixth rotational element N 6 .

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 that supports the third pinion P 3 externally engaged with a third sun gear S 3 , and a third ring gear R 3 that is internally engaged with the third pinion P. The third sun gear S 3 acts as a seventh rotational element N 7 , the third planet carrier PC 3 acts as a eighth rotational element N 8 , and the third ring gear R 3 acts as a ninth rotational element N 9 .

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 that supports the fourth pinion P 4 externally engaged with the fourth sun gear S 4 , and a fourth ring gear R 4 that is internally engaged with the fourth pinion P 4 . The fourth sun gear S 4 acts as a tenth rotational element N 10 , the fourth planet carrier PC 4 acts as an eleventh rotational element N 11 , and the fourth ring gear R 4 acts as a twelfth rotational element N 12 .

In the arrangement of the first, second, and third planetary gear sets PG 1 , PG 2 , and PG 3 , the second rotational element N 2 is fixedly connected with the fifth rotational element N 5 , and the fourth rotational element N 4 is fixedly connected with the seventh rotational element N 7 , by a corresponding shaft selected from seven shafts TM 1 to TM 7 .

Three shafts TM 8 to TM 10 are fixedly connected to the fourth planetary gear set PG 4 .

The ten shafts TM 1 to TM 10 are hereinafter described in detail.

Each of the ten shafts TM 1 -TM 10 may be a rotational member that fixedly interconnects the input and output shafts and rotational elements of the planetary gear set PG 1 , PG 2 , PG 3 , and PG 4 , may be a rotational member that selectively interconnect the rotational element and the transmission housing H, or may be a fixed member that fixedly connect the rotational element to the transmission housing H.

The first shaft TM 1 is fixedly connected with the first rotational element N 1 (first sun gear S 1 ).

The second shaft TM 2 is fixedly connected with the second rotational element N 2 (first ring gear R 1 ) and the fifth rotational element N 5 (second planet carrier PC 2 ).

The third shaft TM 3 is fixedly connected with the third rotational element N 3 (first planet carrier PC 1 ), selectively connected with the first shaft TM 1 , and also fixedly connected with the input shaft IS, thereby always acting as an input element.

The fourth shaft TM 4 fixedly interconnects the fourth rotational element N 4 (second sun gear S 2 ) and the seventh rotational element N 7 (third sun gear S 3 ), and is selectively connected with the transmission housing H.

The fifth shaft TM 5 is fixedly connected with the sixth rotational element N 6 (second ring gear R 2 ), and is selectively connected with the first shaft TM 1 .

The sixth shaft TM 6 is fixedly connected with the eighth rotational element N 8 (third planet carrier PC 3 ), and is selectively connected with the fifth shaft TM 5 .

The seventh shaft TM 7 is fixedly connected with the ninth rotational element N 9 (third ring gear R 3 ), and is selectively connected with the transmission housing H.

The eighth shaft TM 8 is fixedly connected with the tenth rotational element N 10 (fourth sun gear S 4 ), and is externally gear-meshed with the first shaft TM 1 .

The ninth shaft TM 9 is fixedly connected with the eleventh rotational element N 11 (fourth planet carrier PC 4 ), and is also fixedly connected with the output shaft OS, thereby always acting as an output element.

The tenth shaft TM 10 is fixedly connected with the twelfth rotational element N 12 (fourth ring gear R 4 ), and is externally gear-meshed with the sixth shaft TM 6 .

The two transfer gears TF 1 and TF 2 deliver a shifted torque of the main shifting portion having the first, second, and third planetary gear sets PG 1 , PG 2 , and PG 3 to the auxiliary shifting portion having the fourth planetary gear set PG 4 .

The first transfer gear TF 1 includes a first transfer drive gear TF 1 a connected with the first shaft TM 1 and a first transfer driven gear TF 1 b connected with the eighth shaft TM 8 , such that the first transfer gear TF 1 externally gear-meshes the first shaft TM 1 and the eighth shaft TM 8 .

The second transfer gear TF 2 includes a second transfer drive gear TF 2 a connected with the sixth shaft TM 6 and a second transfer driven gear TF 2 b connected with the tenth shaft TM 10 , such that the second transfer gear TF 2 externally gear-meshes the sixth shaft TM 6 and the tenth shaft TM 10 .

As a result, respective shafts connected by the first and second transfer gears TF 1 and TF 2 rotate in opposite directions, and the gear ratios of the first and second transfer gears TF 1 and TF 2 may be preset in consideration of desired speed ratio of the transmission.

The control elements include three clutches C 1 , C 2 , and C 3 and two brakes B 1 and B 2 , and are arranged as follows.

The first clutch C 1 is arranged between the first shaft TM 1 and the third shaft TM 3 such that the first shaft TM 1 and the third shaft TM 3 may selectively connected with each other.

The second clutch C 2 is arranged between the first shaft TM 1 and the fifth shaft TM 5 such that the first shaft TM 1 and the fifth shaft TM 5 may selectively connected with each other.

The third clutch C 3 is arranged between the fifth shaft TM 5 and the sixth shaft TM 6 such that the fifth shaft TM 5 and the sixth shaft TM 6 may selectively connected with each other.

The first brake B 1 is arranged between the fourth shaft TM 4 and the transmission housing H such that the fourth shaft TM 4 may selectively act as a fixed element.

The second brake B 2 is arranged between the seventh shaft TM 7 and the transmission housing H such that the seventh shaft TM 7 may selectively act as a fixed element.

In the first exemplary form of the present disclosure, the first clutch C 1 selectively connects the first shaft TM 1 and the third shaft TM 3 . Herein, the first clutch C 1 selectively connects at least two rotational elements among the first, second, and third rotational element N 1 , N 2 , and N 3 of the first planetary gear set PG 1 such that the first planetary gear set PG 1 may integrally rotate. The first clutch C 1 selectively connects two shafts among the first shaft TM 1 , second shaft TM 2 , and third shaft TM 3 , such that the first planetary gear set PG 1 becomes locked and integrally rotates

Herein, the control elements of the first, second, third clutch C 1 , C 2 , and C 3 , the first, second brake B 1 and B 2 as hydraulic friction coupling units which are operated by hydraulic pressure supplied from a hydraulic control device primarily adopt a wet multi-disk type hydraulic friction coupling unit. But the control elements may be constituted by a coupling unit such as a dog clutch, an electronic clutch and a magnetic particle clutch which may be operated according to an electric signal supplied from an electronic control device

FIG. 2 is an operational chart for respective control elements at respective shift-stages in a planetary gear train according to a first exemplary form of the present disclosure.

Referring to FIG. 2 , a planetary gear train according to a first exemplary form of the present disclosure realizes shifting by operating three control elements among the three clutches C 1 , C 2 , and C 3 and the two brakes B 1 and B 2 .

[The Forward First Speed]

In the forward first speed shift-stage D 1 , the first clutch C 1 and the first and second brakes B 1 and B 2 are simultaneously operated.

As a result, the first shaft TM 1 is connected with the third shaft TM 3 by the operation of the first clutch C 1 . In this state, the torque of the input shaft IS is input to the third shaft TM 3 , and the fourth and seventh shaft TM 4 and TM 7 acts as a fixed element by the operation of the first and second brakes B 1 and B 2 , thereby realizing the forward first speed by operation of respective shafts and outputting a shifted torque to the output shaft OS connected with the ninth shaft TM 9 .

[The Forward Second Speed]

In the forward second speed shift-stage D 2 , the second clutch C 2 and the first and second brakes B 1 and B 2 are simultaneously operated.

As a result, the first shaft TM 1 is connected with the fifth shaft TM 5 by the operation of the second clutch C 2 . In this state, the torque of the input shaft IS is input to the third shaft TM 3 , and the fourth and seventh shaft TM 4 and TM 7 act as a fixed element by the operation of the first and second brakes B 1 and B 2 , thereby realizing the forward second speed by operation of respective shafts and outputting a shifted torque to the output shaft OS connected with the ninth shaft TM 9 .

[The Forward Third Speed]

In the forward third speed shift-stage D 3 , the first clutch C 1 , the second clutch C 2 and the second brake B 2 are simultaneously operated.

As a result, the first shaft TM 1 is connected with the third shaft TM 3 by the operation of the first clutch C 1 , and the first shaft TM 1 is connected with the fifth shaft TM 5 in the operation of the second clutch C 2 . In this state, the torque of the input shaft IS is input to the third shaft TM 3 , and the seventh shaft TM 7 acts as a fixed element by the operation of the second brake B 2 , thereby realizing the forward third speed by operation of respective shafts and outputting a shifted torque to the output shaft OS connected with the ninth shaft TM 9 .

[The Forward Fourth Speed]

In the forward fourth speed shift-stage D 4 , the second C 2 , the third clutch C 3 , and the second brake B 2 are simultaneously operated.

As a result, the first shaft TM 1 is connected with the fifth shaft TM 5 by the operation of the second clutch C 2 , and the fifth shaft TM 5 is connected with the sixth shaft TM 6 by the operation of the third clutch C 3 . In this state, the torque of the input shaft IS is input to the third shaft TM 3 , and the seventh shaft TM 7 acts as a fixed element by the operation of the second brake B 2 , thereby realizing the forward fourth speed by operation of respective shafts and outputting a shifted torque to the output shaft OS connected with the ninth shaft TM 9 .

[The Forward Fifth Speed]

In the forward fifth speed shift-stage D 5 , the first C 1 , the third clutch C 3 , and the second brake B 2 are simultaneously operated.

As a result, the first shaft TM 1 is connected with the third shaft TM 3 by the operation of the first clutch C 1 , and the fifth shaft TM 5 is connected with the sixth shaft TM 6 by the operation of the third clutch C 3 . In this state, the torque of the input shaft IS is input to third shaft TM 3 , and the seventh shaft TM 7 acts as a fixed element by the operation of the second brake B 2 , thereby realizing the forward fifth speed by operation of respective shafts and outputting a shifted torque to the output shaft OS connected with the ninth shaft TM 9 .

[The Forward Sixth Speed]

In the forward sixth speed shift-stage D 6 , the first clutch C 1 , the second clutch C 2 , and the third clutch C 3 are simultaneously operated.

As a result, the first shaft TM 1 is connected with the third shaft TM 3 by the operation of the first clutch C 1 , the first shaft TM 1 is connected with the fifth shaft TM 5 by the operation of the second clutch C 2 , and the fifth shaft TM 5 is connected with the sixth shaft TM 6 by the operation of the third clutch C 3 . In this state, the torque of the input shaft IS is input to the third shaft TM 3 , thereby realizing the forward sixth speed by operation of respective shafts and outputting a shifted torque to the output shaft OS connected with the ninth shaft TM 9 .

[The Forward Seventh Speed]

In the forward seventh speed shift-stage D 7 , the first clutch C 1 , the third clutch C 3 , and the first brake B 1 are simultaneously operated.

As a result, the first shaft TM 1 is connected with the third shaft TM 3 by the operation of the first clutch C 1 , and the fifth shaft TM 5 is connected with the sixth shaft TM 6 by the operation of the third clutch C 3 . In this state, the torque of the input shaft IS is input to the third shaft TM 3 , and the fourth shaft TM 4 acts as a fixed element by the operation of the first brake B 1 , thereby realizing the forward seventh speed by operation of respective shafts and outputting a shifted torque to the output shaft OS connected with the ninth shaft TM 9 .

[The Forward Eighth Speed]

In the forward eighth speed shift-stage D 8 , the second clutch C 2 , the third clutch C 3 , and the first brake B 1 are simultaneously operated.

As a result, the first shaft TM 1 is connected with the fifth shaft TM 5 by the operation of the second clutch C 2 , and the fifth shaft TM 5 is connected with the sixth shaft TM 6 by the operation of the third clutch C 3 . In this state, the torque of the input shaft IS is input to the third shaft TM 3 , and the fourth shaft TM 4 acts as a fixed element by the operation of the first brake B 1 , thereby realizing the forward eighth speed by operation of respective shafts and outputting a shifted torque to the output shaft OS connected with the ninth shaft TM 9 .

[The Reverse Speed]

In the reverse speed shift-stage REV, the third clutch C 3 , the first brake B 1 , and the second brake B 2 are simultaneously operated.

As a result, the fifth shaft TM 5 is connected with the sixth shaft TM 6 by the operation of the third clutch C 3 . In this state, the torque of the input shaft IS is input to the third shaft TM 3 , and the fourth shaft TM 4 and the seventh shaft TM 7 act as fixed element by the operation of the first brake B 1 and the second brake B 2 , thereby realizing the reverse speed by operation of respective shafts and outputting a shifted torque to the output shaft OS connected with the ninth shaft TM 9 .

FIG. 3 is a schematic diagram of a planetary gear train according to a second exemplary form of the present disclosure.

According to a planetary gear train according to a first exemplary form of the present disclosure, the first clutch C 1 for unifying the first planetary gear set PG 1 is arranged between the first shaft TM 1 and the third shaft TM 3 as shown in FIG. 1 . However, in a planetary gear train according to a second exemplary form as illustrated in FIG. 3 , the first clutch C 1 is arranged between the first shaft TM 1 and the second shaft TM 2 .

As a result, the second exemplary form shows the same function and operation, while being different from the first exemplary form in a mere location of the first clutch C 1 .

FIG. 4 is a schematic diagram of a planetary gear train according to a third exemplary form of the present disclosure.

According to a planetary gear train according to a first exemplary form of the present disclosure, the first clutch C 1 for unifying the first planetary gear set PG 1 is arranged between the first shaft TM 1 and the third shaft TM 3 as shown in FIG. 1 . However, in a planetary gear train according to a third exemplary form as illustrated in FIG. 4 , the first clutch C 1 is arranged between the second shaft TM 2 and the third shaft TM 3 .

As a result, the third exemplary form shows the same function and operation, while being different from the first exemplary form in a mere location of the first clutch C 1 .

As described above, according to a planetary gear train according to an exemplary form of the present disclosure, at least eight forward speeds and at least one reverse speed may be realized by a combination of four planetary gear sets, two transfer gears, and five control elements, thereby providing improvement of power delivery performance and fuel consumption and improving installability by shortening the length of an automatic transmission.

In addition, according to a planetary gear train according to an exemplary form of the present disclosure, two transfer gears of external gears arranged on the output shaft OS are employed in addition to three planetary gear sets, and thus, gear teeth may be widely varied so as to easily achieve desired gear ratio and to easily comply with desired performance for respective vehicles.

In addition, according to a planetary gear train according to an exemplary form of the present disclosure, a gear ratio span of more than 8.8 may be achieved while realizing at least eight forward speeds and at least one reverse speed, thereby increasing an engine driving efficiency.

In addition, the linearity of step ratios of shift stages is secured while multi-staging the shift stage with high efficiency, thereby making it possible to improve drivability such as acceleration before and after a gear shift, an engine speed rhythmic sense, and the like.

In addition, five control elements are applied to the planetary gear train according to an exemplary form of the present disclosure, thereby making it possible to reduce material cost due to reduction of constituent components, and reduce non-controlled control elements so as to reduce a drag torque, and improve a power transmission efficiency so as to reduce fuel consumption.

While this present disclosure has been described in connection with what is presently considered to be practical exemplary forms, it is to be understood that the present disclosure is not limited to the disclosed forms, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

PG 1 ,PG 2 ,PG 3 ,PG 4 . . . first, second, third, fourth planetary gear set

S 1 ,S 2 ,S 3 ,S 4 . . . first, second, third, fourth sun gear

PC 1 ,PC 2 ,PC 3 ,PC 4 . . . first, second, third, fourth planet carrier

R 1 ,R 2 ,R 3 ,R 4 . . . first, second, third, fourth ring gear

IS . . . input shaft

OS . . . output shaft

B 1 ,B 2 . . . first, second brake

C 1 ,C 2 ,C 3 . . . first, second, third clutch

TF 1 ,TF 2 . . . first, second transfer gear

TM 1 ,TM 2 ,TM 3 ,TM 4 ,TM 5 ,TM 6 ,TM 7 ,TM 8 ,TM 9 ,TM 10 . . . first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth shaft

While this present disclosure has been described in connection with what is presently considered to be practical exemplary forms, it is to be understood that the present disclosure is not limited to the disclosed forms, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.