Planetary gear train of automatic transmission for vehicles

This application claims priority to and the benefit of Korean Patent Application No. 10-2017-0052121, 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 regards, research on an automatic transmission has been performed 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 impact on installability, production cost, weight and/or power flow efficiency.

In order 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 undermining 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.

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 and improving installability by reducing a length of the transmission.

In addition, a wide available range of gear teeth of transfer gears enables easily obtaining desired 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 and the fourth rotational element; a second shaft fixedly connected with the second rotational element and connected with the input shaft; a third shaft fixedly connected with the third rotational element and the ninth rotational element; a fourth shaft fixedly connected with the fifth rotational element; a fifth shaft fixedly connected with the sixth rotational element; a sixth shaft fixedly connected with the seventh rotational element; a seventh shaft fixedly connected with the eighth rotational element; a eighth shaft fixedly connected with the tenth rotational element and externally engaged with the sixth shaft; a ninth shaft fixedly connected with the eleventh rotational element and connected with the output shaft; a tenth shaft fixedly connected with the twelfth rotational element and externally engaged with the fourth shaft; and two transfer gears externally gear-meshed with the fourth and sixth shafts respectively.

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

The first planetary gear set may include a first sun gear as the first rotational element, a first planet carrier as the second rotational element, and a first ring gear as the third rotational element; the second planetary gear set may include 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 may include a third sun gear as the seventh rotational element, a third ring gear as the eighth rotational element, and a third planet carrier as the ninth rotational element; and the fourth planetary gear set may include 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 third, first, and second planetary gear sets from an engine side.

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

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

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

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

The planetary gear train may further include a first clutch arranged between the input shaft and the sixth shaft; a second clutch arranged between the third shaft and the sixth shaft; a third clutch arranged between the fourth shaft and the seventh shaft; a first brake arranged between the first shaft and the transmission housing; and a second brake arranged between the fifth 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 of the transmission 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 ratios 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, it is possible to realize 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 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.

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 present disclosure.

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 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 set PG 1 , PG 2 , and PG 3 are arranged on the input shaft IS in the order of the third, first, and second planetary gear set PG 3 , PG 1 , and PG 2 from an engine side.

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 single pinion planetary gear set, and includes a first sun gear S 1 , a first planet carrier PC 1 that supports a first pinion P 1 externally engaged with the first sun gear S 1 , and a first ring gear R 1 that is internally engaged with the first pinion P 1 . The first sun gear S 1 acts as a first rotational element N 1 , the first planet carrier PC 1 acts as a second rotational element N 2 , and the first ring gear R 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 a second pinion P 2 externally engaged with the second sun gear S 2 , and a second ring gear R 2 that 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 double pinion planetary gear set, and includes a third sun gear S 3 , a third ring gear R 3 that externally engaged with a third pinion P 3 externally engaged with the third sun gear S 3 , and a third planet carrier PC 3 that supports the third pinion P 3 . The third sun gear S 3 acts as a seventh rotational element N 7 , the third ring gear R 3 acts as an eighth rotational element N 8 , and the third planet carrier PC 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 fourth pinion P 4 externally engaged with the fourth sun gear S 4 , and a fourth ring gear R 4 that 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 first rotational element N 1 is fixedly connected with the fourth rotational element N 4 , and the third rotational element N 3 is fixedly connected with the ninth rotational element N 9 , by corresponding shafts 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 sets PG 1 , PG 2 , PG 3 , and PG 4 , may be a rotational member that selectively interconnects the rotational element and a transmission housing H, or may be a fixed member that fixedly connects 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 } and the fourth rotational element N 4 (second sun gear S 2 ), and selectively connected with the transmission housing H.

The second shaft TM 2 is fixedly connected with the second rotational element N 2 (first planet carrier PC 1 ) and the input shaft IS, thereby always acting as an input element.

The third shaft TM 3 is fixedly connected with the third rotational element N 3 (first ring gear R 1 ) and the ninth rotational element N 9 (third planet carrier PC 3 ).

The fourth shaft TM 4 is fixedly connected with the fifth rotational element N 5 (second planet carrier PC 2 ).

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

The sixth shaft TM 6 is fixedly connected with the seventh rotational element N 7 (third sun gear S 3 ), and is selectively connected with the input shaft IS.

The seventh shaft TM 7 is fixedly connected with the eighth rotational element N 8 (third ring gear R 3 ), and is selectively connected with the fourth shaft TM 4 and the sixth shaft TM 6 respectively.

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 sixth shaft TM 6 .

The ninth shaft TM 9 is fixedly connected with the eleventh rotational element N 11 (fourth planet carrier PC 4 ) and 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 fourth shaft TM 4 .

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 fourth shaft TM 4 , and a first transfer driven gear TF 1 b connected with the tenth shaft TM 10 , and the first transfer gear TF 1 externally gear-meshes the fourth shaft TM 4 and the tenth shaft TM 10 .

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 eighth shaft TM 8 , and the second transfer gear TF 2 externally gear-meshes the sixth shaft TM 6 and the eighth shaft TM 8 .

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 input shaft IS and the sixth shaft TM 6 such that the input shaft IS and the sixth shaft TM 6 may selectively connected with each other.

The second clutch C 2 is arranged between the sixth shaft TM 6 and the seventh shaft TM 7 such that the sixth shaft TM 6 and the seventh shaft TM 7 may selectively connected with each other.

The third clutch C 3 is arranged between the fourth shaft TM 4 and the seventh shaft TM 7 such that the fourth shaft TM 4 and the seventh shaft TM 7 may selectively connected with each other.

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

The second brake B 2 is arranged between the fifth shaft TM 5 and the transmission housing H such that the fifth shaft TM 5 may selectively act as a fixed element.

In the first exemplary form of the present disclosure, the second clutch C 2 selectively connects the sixth shaft TM 6 and the seventh shaft TM 7 . Herein, the second clutch C 2 connects at least two rotational elements among the seventh, eighth, and ninth rotational elements N 7 , N 8 , and N 9 of the third planetary gear set PG 3 such that the first planetary gear set PG 1 may integrally rotate. The second clutch C 2 selectively connects two shafts among the third shaft TM 3 , the sixth shaft TM 6 , and the seventh shaft TM 7 , such that the third planetary gear set PG 3 becomes locked and integrally rotates.

Herein, the control elements of the first, second and third clutches (C 1 , C 2 , and C 3 ), and the first and second brakes (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 sixth shaft TM 6 is connected with the input shaft IS by the operation of the first clutch C 1 . In this state, the torque of the input shaft IS is input to the second shaft TM 2 and the sixth shaft TM 6 , and the first shaft TM 1 and the fifth shaft TM 5 act as a fixed element by the operation of the first brake B 1 and the second brake 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 sixth shaft TM 6 is connected with the seventh shaft TM 7 by the operation of the second clutch C 2 . In this state, the torque of the input shaft IS is input to the second shaft TM 2 , and the first shaft TM 1 and the fifth shaft TM 5 act as a fixed element by the operation of the first brake B 1 and the second brake 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 sixth shaft TM 6 is connected with the input shaft IS by the operation of the first clutch C 1 , and the sixth shaft TM 6 is connected with the seventh shaft TM 7 by the operation of the second clutch C 2 . In this state, the torque of the input shaft IS is input to the second shaft TM 2 and the sixth shaft TM 6 , and the fifth shaft TM 5 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 sixth shaft TM 6 is connected with the seventh shaft TM 7 by the operation of the second clutch C 2 , and the fourth shaft TM 4 is connected with the seventh shaft TM 7 by the operation of the third clutch C 3 . In this state, the torque of the input shaft IS is input to the second shaft TM 2 , and the fifth shaft TM 5 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 sixth shaft TM 6 is connected with the input shaft IS by the operation of the first clutch C 1 , and the fourth shaft TM 4 is connected with the seventh shaft TM 7 by the operation of the third clutch C 3 . In this state, the torque of the input shaft IS is input to the second shaft TM 2 and the sixth shaft TM 6 , and the fifth shaft TM 5 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 sixth shaft TM 6 is connected with the input shaft IS by the operation of the first clutch C 1 , the sixth shaft TM 6 is connected with the seventh shaft TM 7 by the operation of the second clutch C 2 , and the fourth shaft TM 4 is connected with the seventh shaft TM 7 by the operation of the third clutch C 3 . In this state, the torque of the input shaft IS is input to the second shaft TM 2 and the sixth shaft TM 6 , 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 sixth shaft TM 6 is connected with the input shaft IS by the operation of the first clutch C 1 , and the fourth shaft TM 4 is connected with the seventh shaft TM 7 by the operation of the third clutch C 3 . In this state, the torque of the input shaft IS is input to the second shaft TM 2 and the sixth shaft TM 6 , and the first shaft TM 1 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 sixth shaft TM 6 is connected with the seventh shaft TM 7 by the operation of the second clutch C 2 , and the fourth shaft TM 4 is connected with the seventh shaft TM 7 by the operation of the third clutch C 3 . In this state, the torque of the input shaft IS is input to the second shaft TM 2 , and the first shaft TM 1 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 fourth shaft TM 4 is connected with the seventh shaft TM 7 by the operation of the third clutch C 3 . In this state, the torque of the input shaft IS is input to the second shaft TM 2 , the first shaft TM 1 and the fifth shaft TM 5 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 second clutch C 2 for unifying the third planetary gear set PG 3 is arranged between the sixth shaft TM 6 and the seventh shaft TM 7 as shown in FIG. 1 . However, in a planetary gear train according to a second exemplary form as illustrated in FIG. 3 , the second clutch C 2 is arranged between the third shaft TM 3 and the seventh shaft TM 7 .

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 second clutch C 2 .

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 second clutch C 2 for unifying the third planetary gear set PG 3 is arranged between the sixth shaft TM 6 and the seventh shaft TM 7 as shown in FIG. 1 . However, in a planetary gear train according to a third exemplary form as illustrated in FIG. 4 , the second clutch C 2 is arranged between the third shaft TM 3 and the sixth shaft TM 6 .

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 second clutch C 2 .

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 four planetary gear sets, and thus, gear teeth may be widely varied so as to easily achieve desired gear ratios 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, it is possible to realize 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 present disclosure.

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

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

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

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

IS . . . input shaft

OS . . . output shaft

B 1 , B 2 . . . first, second brakes

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

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

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 shafts

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 present disclosure.