Planetary gear train of automatic transmission for vehicle

The present application claims priority to Korean Patent Application No. 10-2017-0165916 filed on Dec. 5, 2017, the entire contents of which is incorporated herein for all purposes by this reference.

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

In the field of an automatic transmission, more multiplicity of shift-stages is useful technology for enhancement of fuel consumption and drivability of a vehicle.

Achieving more shift stages contributes to maximize performance and efficiency of a vehicle in a so-called downsizing trend of an engine, and more linearity in step ratios of the shift-stages enhances drivability of the vehicle by improving uniformity of acceleration before and after a shifting, etc.

To achieve more shift-stages for an automatic transmission, the number of parts is typically increased, which may deteriorate installability, production cost, weight and/or power flow efficiency.

Therefore, to maximally enhance fuel consumption of an automatic transmission having more shift-stages, it is important that better efficiency is derived by less number of parts.

In this background, an eight-speed automatic transmission has been introduced recently and a planetary gear train for an automatic transmission facilitating more shift-stages is under investigation.

A recent eight-speed automatic transmission typically shows a gear ratio span, which is a significant factor for linearity of step ratios, in a level of 6.5 to 7.5, which may require improvement for better fuel consumption.

In addition, an eight-speed automatic transmission may become inferior in respect of linearity of step ratios of shift-stages even if the gear ratio span may become a level of above 9.0. Thus, high efficiency automatic transmission providing at least nine forward speeds may be more appropriate for enhancing driving efficiency and drivability of a vehicle.

The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and may 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 providing a planetary gear train of an automatic transmission for a vehicle facilitating at least ten forward speeds, providing better performance and fuel efficiency of a vehicle.

An exemplary planetary gear train of an automatic transmission for a vehicle may include an input shaft receiving an input torque, an output shaft outputting a shifted torque, a first planetary gear set having first, second, and third rotation elements, a second planetary gear set having fourth, fifth, and sixth rotation elements, a third planetary gear set having seventh, eighth, and ninth rotation elements, a fourth planetary gear set having tenth, eleventh, and twelfth rotation elements, a fifth planetary gear set having thirteenth, fourteenth, and fifteenth rotation elements, a first shaft fixedly connected to the first rotation element, the fifth rotation element, and the input shaft, a second shaft fixedly connected to the fourteenth rotation element and the output shaft, a third shaft fixedly connected to the third rotation element and the fourth rotation element, a fourth shaft fixedly connected to the sixth rotation element and the tenth rotation element, a fifth shaft fixedly connected to the eighth rotation element, the eleventh rotation element, and the fifteenth rotation element, a sixth shaft fixedly connected to the ninth rotation element, and a plurality of shafts, each of which is selectively connectable to the transmission housing and fixedly connected to a rotation element of the first, third, fourth, and fifth planetary gear sets which is not fixedly connected to any of the first to sixth shafts.

The plurality of shafts may include a seventh shaft fixedly connected to the second rotation element and the seventh rotation element and selectively connectable to the transmission housing, an eighth shaft fixedly connected to the twelfth rotation element and selectively connectable to the transmission housing, and a ninth shaft fixedly connected to the thirteenth rotation element and selectively connectable to the transmission housing. The second shaft and the fourth shaft, the first shaft and the sixth shaft, and the third shaft and the sixth shaft may be selectively connectable to each other, respectively.

The planetary gear train may further include three clutches each selectively connecting a corresponding pair among the input shaft, the output shaft, and the first to ninth shafts, and three brakes selectively connecting the seventh shaft, the eighth shaft, and the ninth shaft to the transmission housing respectively.

The three clutches may include a first clutch disposed between the second shaft and the fourth shaft, a second clutch disposed between the first shaft and the sixth shaft, and a third clutch disposed between the third shaft and the sixth shaft. The three brakes may include a first brake disposed between the seventh shaft and the transmission housing, a second brake disposed between the eighth shaft and the transmission housing, and a third brake disposed between the ninth shaft and the transmission housing.

The three clutches may include a first clutch disposed between the second shaft and the fourth shaft, a second clutch disposed between the first shaft and the sixth shaft, and a third clutch disposed between the third shaft and the fifth shaft. The three brakes may include a first brake disposed between the seventh shaft and the transmission housing, a second brake disposed between the eighth shaft and the transmission housing, and a third brake disposed between the ninth shaft and the transmission housing.

The first, second, and third rotation elements may be respectively a first sun gear, a first planet carrier, and a first ring gear. The fourth, fifth, and sixth rotation elements may be respectively a second sun gear, a second planet carrier, and a second ring gear. The seventh, eighth, and ninth rotation elements may be respectively a third sun gear, a third planet carrier, and a third ring gear. The tenth, eleventh, and twelfth rotation elements may be respectively a fourth sun gear, a fourth planet carrier, and a fourth ring gear. The thirteenth, fourteenth, and fifteenth rotation elements may be respectively a fifth sun gear, a fifth planet carrier, and a fifth ring gear.

The first, second, third, fourth, and fifth planetary gear sets may be disposed in the order of the first, third, second, fourth, and fifth planetary gear sets from an input side thereof.

As described above, a planetary gear train according to an exemplary embodiment of the present invention may realize ten forward speeds and one reverse speed by operating five planetary gear sets by six engagement elements.

Furthermore, a gear ratio span may be increased to above 8.8 maximizing engine efficiency, and step ratios of shift-stages may become more linear, improving acceleration and engine drivability before and after a shifting.

Furthermore, the number of engagement elements employed to realize ten forward speeds and one reverse speed is minimized, improving power delivery efficiency and fuel consumption by minimizing drag loss of an automatic transmission.

Furthermore, a torque in parallel scheme is employed in a planetary gear set at an output side, and torque loads applied to engagement elements of respective planetary gear sets become more uniform, improving torque delivery efficiency and durability of an automatic transmission.

Furthermore, a minimal number of engagement elements are controlled to realize shifting between shift-stages of ten forward speeds and one reverse speed, and accordingly, reduction of clutch drag, enhancement of torque transmission efficiency, and enhancement of flexibility of output gear ratios, enhancing linearity of step ratios.

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 a planetary gear train according to various exemplary embodiments of the present invention.

FIG. 2 is an operational chart for respective control elements at respective shift-stages applicable to a planetary gear train according to various exemplary embodiments of the present invention.

FIG. 3 is a schematic diagram of a planetary gear train according to various exemplary embodiments of the present invention.

It may be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the invention. The specific design features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particularly intended application and use environment.

In the figures, reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing.

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 the 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.

Hereinafter, an exemplary embodiment of the present invention will be described in detail with reference to drawings.

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 or substantially the same as each other and an order thereof is not particularly limited.

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

Referring to FIG. 1 , a planetary gear train according to various exemplary embodiments of the present invention includes first, second, third, fourth, and fifth planetary gear sets PG 1 , PG 2 , PG 3 , PG 4 , and PG 5 disposed on a same axis, an input shaft IS, an output shaft OS, nine shafts TM 1 to TM 9 interconnecting rotation elements of the first, second, third, fourth, and fifth planetary gear sets PG 1 , PG 2 , PG 3 , PG 4 , and PG 5 , engagement elements of three clutches C 1 to C 3 and three brakes B 1 to B 3 , and a transmission housing H.

A torque of an engine input to the input shaft IS is shifted by cooperative operation of the first, second, third, fourth, and fifth planetary gear sets PG 1 , PG 2 , PG 3 , PG 4 , and PG 5 , and a shifted torque is output through the output shaft OS.

According to various exemplary embodiments of the present invention, the planetary gear sets are disposed in the order of the first, third, second, fourth, and fifth planetary gear sets PG 1 , PG 3 , PG 2 , PG 4 , and PG 5 , from an engine side thereof.

The input shaft IS is an input member and may receive a torque from a crankshaft of an engine through a torque converter.

The output shaft OS is an output element disposed on a same axis with the input shaft IS, and outputs a shifted driving torque to a driveshaft through a differential apparatus.

The first planetary gear set PG 1 is a single pinion planetary gear set, and includes a first sun gear S 1 , a first planet carrier PC 1 rotatably supporting a plurality of first pinion gears P 1 externally gear-meshed with the first sun gear S 1 , and a first ring gear R 1 internally gear-meshed with the plurality of first pinion gears P 1 . The first sun gear S 1 acts as a first rotation element N 1 , the first planet carrier PC 1 acts as a second rotation element N 2 , and the first ring gear R 1 acts as a third rotation 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 rotatably supporting a plurality of second pinion gears P 2 externally gear-meshed with the second sun gear S 2 , and a second ring gear R 2 internally gear-meshed with the plurality of second pinion gears P 2 . The second sun gear S 2 acts as a fourth rotation element N 4 , the second planet carrier PC 2 acts as a fifth rotation element N 5 , and the second ring gear R 2 acts as a sixth rotation 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 rotatably supporting a plurality of third pinion gears P 3 externally gear-meshed with the third sun gear S 3 , and a third ring gear R 3 internally gear-meshed with the plurality of third pinion gears P 3 . The third sun gear S 3 acts as a seventh rotation element N 7 , the third planet carrier PC 3 acts as an eighth rotation element N 8 , and the third ring gear R 3 acts as a ninth rotation 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 rotatably supporting a plurality of fourth pinion gears P 4 externally gear-meshed with the fourth sun gear S 4 , and a fourth ring gear R 4 internally gear-meshed with the plurality of fourth pinion gears P 4 . The fourth sun gear S 4 acts as a tenth rotation element N 10 , the fourth planet carrier PC 4 acts as an eleventh rotation element N 11 , and the fourth ring gear R 4 acts as a twelfth rotation element N 12 .

The fifth planetary gear set PG 5 is a single pinion planetary gear set, and includes a fifth sun gear S 5 , a fifth planet carrier PC 5 rotatably supporting a plurality of fifth pinion gears P 5 externally gear-meshed with the fifth sun gear S 5 , and a fifth ring gear R 5 internally gear-meshed with the plurality of fifth pinion gears P 5 . The fifth sun gear S 5 acts as a thirteenth rotation element N 13 , the fifth planet carrier PC 5 acts as a fourteenth rotation element N 14 , and the fifth ring gear R 5 acts as a fifteenth rotation element N 15 .

In the arrangement of the first, second, third, fourth, and fifth planetary gear sets PG 1 , PG 2 , PG 3 , PG 4 , and PG 5 , the first rotation element N 1 and the fifth rotation element N 5 are fixedly interconnected, the third rotation element N 3 and the fourth rotation element N 4 are fixedly interconnected, the sixth rotation element N 6 and the tenth rotation element N 10 are fixedly interconnected, the eighth rotation element N 8 , the eleventh rotation element N 11 , and the fifteenth rotation element N 15 are fixedly interconnected, and the second rotation element N 2 and the seventh rotation element N 7 are fixedly interconnected, forming nine shafts TM 1 to TM 9 .

The nine shafts TM 1 to TM 9 are hereinafter described more specifically.

The first shaft TM 1 is fixedly connected to first rotation element N 1 (first sun gear S 1 ) and fifth rotation element N 5 (second planet carrier PC 2 ), and fixedly connected to the input shaft IS, always acting as an input element.

The second shaft TM 2 is fixedly connected to the fourteenth rotation element N 14 (fifth planet carrier PC 5 ), and fixedly connected to the output shaft OS always acting as an output element.

The third shaft TM 3 is fixedly connected to the third rotation element N 3 (first ring gear R 1 ) and the fourth rotation element N 4 (second sun gear S 2 ).

The fourth shaft TM 4 is fixedly connected to the sixth rotation element N 6 (second ring gear R 2 ) and the tenth rotation element N 10 (fourth sun gear S 4 ).

The fifth shaft TM 5 is fixedly connected to the eighth rotation element N 8 (third planet carrier PC 3 ), the eleventh rotation element N 11 (fourth planet carrier PC 4 ), and the fifteenth rotation element N 15 (fifth ring gear R 5 ).

The sixth shaft TM 6 is fixedly connected to the ninth rotation element N 9 (third ring gear R 3 ).

The seventh shaft TM 7 is fixedly connected to the second rotation element N 2 (first planet carrier PC 1 ) and the seventh rotation element N 7 (third sun gear S 3 ).

The eighth shaft TM 8 is fixedly connected to the twelfth rotation element N 12 (fourth ring gear R 4 ).

The ninth shaft TM 9 is fixedly connected to the thirteenth rotation element N 13 (fifth sun gear S 5 ).

Each of the nine shafts TM 1 to TM 9 may be a rotation member that fixedly interconnects the input and output shafts and rotation elements of the planetary gear sets PG 1 , PG 2 , PG 3 , and PG 4 , or may be a rotation member that selectively interconnects a rotation element to the transmission housing H, or may be a fixed member fixed to the transmission housing H.

In the disclosure, when two or more members are described to be “fixedly connected”, where each of the members may be any of a shaft, an input shaft, an output shaft, a rotation member, and a transmission housing, it means that the fixedly connected members always rotate at a same speed.

When two or more members are described to be “selectively connectable” by an engagement element, it means that the selectively connectable members rotates separately when the engagement element is not engaged, and rotates at a same speed when the engagement element is engaged. It may be understood that in the case that a member is “selectively connectable” with a transmission housing by an engagement element, the member may be stationary when the engagement element is engaged.

The second shaft TM 2 is selectively connectable to the fourth shaft TM 4 , the first shaft TM 1 is selectively connectable to the sixth shaft TM 6 , and the third shaft TM 3 is selectively connectable to the sixth shaft TM 6 .

Furthermore, the seventh shaft TM 7 , the eighth shaft TM 8 , and ninth shaft TM 9 are selectively connectable to the transmission housing H, selectively acting as a fixed element.

The engagement elements of three clutches C 1 , C 2 , and C 3 are disposed between the nine shafts TM 1 to TM 9 , the input shaft IS, and the output shaft OS, to form selective connections.

The nine shafts TM 1 to TM 9 may be selectively connectable to the transmission housing H, by control elements of three brakes B 1 , B 2 , and B 3 .

The six engagement elements of the three clutches C 1 to C 3 and the three brakes B 1 to B 3 are disposed as follows.

The first clutch C 1 is disposed between the second shaft TM 2 and the fourth shaft TM 4 , and selectively connects the second shaft TM 2 and the fourth shaft TM 4 , controlling power delivery therebetween.

The second clutch C 2 is disposed between the first shaft TM 1 and the sixth shaft TM 6 , and selectively connects the first shaft TM 1 and the sixth shaft TM 6 , controlling power delivery therebetween.

The third clutch C 3 is disposed between the third shaft TM 3 and the sixth shaft TM 6 , and selectively connects the third shaft TM 3 and the sixth shaft TM 6 , controlling power delivery therebetween.

The first brake B 1 is disposed between the seventh shaft TM 7 and the transmission housing H, and selectively connects the seventh shaft TM 7 to the transmission housing H.

The second brake B 2 is disposed between the eighth shaft TM 8 and the transmission housing H, and selectively connects the eighth shaft TM 8 to the transmission housing H.

The third brake B 3 is disposed between the ninth shaft TM 9 and the transmission housing H, and selectively connects the ninth shaft TM 9 to the transmission housing H.

The engagement elements of the first, second, and third clutches C 1 , C 2 , and C 3 and the first, second, and third brakes B 1 , B 2 , and B 3 may be realized as multi-plate hydraulic pressure friction devices that are frictionally engaged by hydraulic pressure, however, it may not be understood to be limited thereto, since various other configuration that are electrically controllable may be available.

FIG. 2 is an operational chart for respective control elements at respective shift-stages applicable to a planetary gear train according to various exemplary embodiments of the present invention.

Referring to FIG. 2 , a planetary gear train according to various exemplary embodiments of the present invention realizes ten forward speeds and one reverse speed by operating three engagements among the first, second, and third clutches C 1 , C 2 , and C 3 and first, second, and third brakes B 1 , B 2 , and B 3 .

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

As a result, the third shaft TM 3 and the sixth shaft TM 6 are connected by the operation of the third clutch C 3 . In the present state, the input torque is input to the first shaft TM 1 .

Furthermore, the eighth and ninth shafts TM 8 and TM 9 act as fixed elements by the operation of the second and third brakes B 2 and B 3 , realizing the first forward speed and outputting a shifted torque to the output shaft OS connected to the second shaft TM 2 .

In the second forward speed D 2 , the second clutch C 2 and the second and third brakes B 2 and B 3 are simultaneously operated.

As a result, the first shaft TM 1 and the sixth shaft TM 6 are connected by the operation of the second clutch C 2 . In the present state, the input torque is input to the first shaft TM 1 .

Furthermore, the eighth and ninth shafts TM 8 and TM 9 act as fixed elements by the operation of the second and third brakes B 2 and B 3 , realizing the second forward speed and outputting a shifted torque to the output shaft OS connected to the second shaft TM 2 .

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

As a result, the first shaft TM 1 and the sixth shaft TM 6 are connected by the operation of the second clutch C 2 . In the present state, the input torque is input to the first shaft TM 1 .

Furthermore, the seventh and ninth shafts TM 7 and TM 9 act as fixed elements by the operation of the first, third brake B 1 and B 3 , realizing the third forward speed and outputting a shifted torque to the output shaft OS connected to the second shaft TM 2 .

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

As a result, the first shaft TM 1 and the sixth shaft TM 6 are connected by the operation of the second clutch C 2 , and the third shaft TM 3 and the sixth shaft TM 6 are connected by the operation of the third clutch C 3 . In the present state, the input torque is input to the first shaft TM 1 .

Furthermore, the ninth shaft TM 9 acts as a fixed element by the operation of the third brake B 3 , realizing the fourth forward speed and outputting a shifted torque to the output shaft OS connected to the second shaft TM 2 .

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

As a result, the second shaft TM 2 and the fourth shaft TM 4 are connected by the operation of the first clutch C 1 , and the first shaft TM 1 and the sixth shaft TM 6 are connected by the operation of the second clutch C 2 . In the present state, the input torque is input to the first shaft TM 1 .

Furthermore, the ninth shaft TM 9 acts as a fixed element by the operation of the third brake B 3 , realizing the fifth forward speed and outputting a shifted torque to the output shaft OS connected to the second shaft TM 2 .

In the sixth forward speed D 6 , the first and third clutches C 1 and C 3 and the third brake B 3 are simultaneously operated.

As a result, the second shaft TM 2 and the fourth shaft TM 4 are connected by the operation of the first clutch C 1 , and the third shaft TM 3 and the sixth shaft TM 6 are connected by the operation of the third clutch C 3 . In the present state, the input torque is input to the first shaft TM 1 .

Furthermore, the ninth shaft TM 9 acts as a fixed element by the operation of the third brake B 3 , realizing the sixth forward speed and outputting a shifted torque to the output shaft OS connected to the second shaft TM 2 .

In the seventh forward speed D 7 , the first, second, and third clutches C 1 , C 2 , and C 3 are simultaneously operated.

As a result, the second shaft TM 2 and the fourth shaft TM 4 are connected by the operation of the first clutch C 1 , the first shaft TM 1 and the sixth shaft TM 6 are connected by the operation of the second clutch C 2 , and the third shaft TM 3 and the sixth shaft TM 6 are connected by the operation of the third clutch C 3 .

As such, the first, second, third, fourth, and fifth planetary gear sets PG 1 , PG 2 , PG 3 , PG 4 , and PG 5 integrally rotate, and the input torque is input to the first shaft TM 1 , realizing the seventh forward speed and outputting a torque as inputted, through the output shaft OS connected to the second shaft TM 2 .

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

As a result, the second shaft TM 2 and the fourth shaft TM 4 are connected by the operation of the first clutch C 1 , and the third shaft TM 3 and the sixth shaft TM 6 are connected by the operation of the third clutch C 3 . In the present state, the input torque is input to the first shaft TM 1 .

Furthermore, the eighth shaft TM 8 acts as a fixed element by the operation of the second brake B 2 , realizing the eighth forward speed and outputting a shifted torque to the output shaft OS connected to the second shaft TM 2 .

In the ninth forward speed D 9 , the first clutch C 1 and the first and second brakes B 1 and B 2 are simultaneously operated.

As a result, the second shaft TM 2 and the fourth shaft TM 4 are connected by the operation of the first clutch C 1 . In the present state, the input torque is input to the first shaft TM 1 .

Furthermore, the seventh and eighth shafts TM 7 and TM 8 act as fixed elements by the operation of the first and second brakes B 1 and B 2 , realizing the ninth forward speed and outputting a shifted torque to the output shaft OS connected to the second shaft TM 2 .

In the tenth forward speed D 10 , the first and second clutch C 1 and C 2 and the second brake B 2 are simultaneously operated.

As a result, the second shaft TM 2 and the fourth shaft TM 4 are connected by the operation of the first clutch C 1 , and the first shaft TM 1 and the sixth shaft TM 6 are connected by the operation of the second clutch C 2 . In the present state, the input torque is input to the first shaft TM 1 .

Furthermore, the eighth shaft TM 8 acts as a fixed element by the operation of the second brake B 2 , realizing the tenth forward speed and outputting a shifted torque to the output shaft OS connected to the second shaft TM 2 .

In the reverse speed REV, the third clutch C 3 and the first and third brakes B 1 and B 3 are simultaneously operated.

As a result, the third shaft TM 3 and the sixth shaft TM 6 are connected by the operation of the third clutch C 3 . In the present state, the input torque is input to the first shaft TM 1 .

Furthermore, the seventh and ninth shafts TM 7 and TM 9 act as fixed elements by the operation of the first, third brake B 1 and B 3 , realizing the reverse speed and outputting a shifted torque to the output shaft OS connected to the second shaft TM 2 .

FIG. 3 is a schematic diagram of a planetary gear train according to various exemplary embodiments of the present invention.

According to a planetary gear train according to various exemplary embodiments of the present invention shown in FIG. 1 , the second clutch C 2 is disposed to selectively connect the third shaft TM 3 and the sixth shaft TM 6 . However, according to a planetary gear train according to various exemplary embodiments of the present invention shown in FIG. 3 , the second clutch C 2 is disposed to selectively connect the third shaft TM 3 and the fifth shaft TM 5 .

Such various exemplary embodiments only differs from the various exemplary embodiments in the arrangement of the second clutch C 2 , and shows the same connection relations between the nine shafts TM 1 to TM 9 , remaining two clutches C 1 and C 3 , and three brakes B 1 to B 3 , providing the same operation.

As described above, a planetary gear train according to an exemplary embodiment of the present invention may realize ten forward speeds and one reverse speed by operating five planetary gear sets PG 1 , PG 2 , PG 3 , PG 4 , and PG 5 by controlling three clutches C 1 , C 2 , and C 3 and three brakes B 1 , B 2 , and B 3 .

Furthermore, a gear ratio span may be increased to above 8.8 maximizing engine efficiency, and step ratios of shift-stages may become more linear, improving acceleration and engine drivability before and after a shifting.

Furthermore, the number of engagement elements employed to realize ten forward speeds and one reverse speed is minimized, improving power delivery efficiency and fuel consumption by minimizing drag loss of an automatic transmission.

Furthermore, a torque in parallel scheme is employed in a planetary gear set at an output side, and torque loads applied to engagement elements of respective planetary gear sets become more uniform, improving torque delivery efficiency and durability of an automatic transmission.

Furthermore, a minimal number of engagement elements are controlled to realize shifting between shift-stages of ten forward speeds and one reverse speed, and accordingly, reduction of clutch drag, enhancement of torque transmission efficiency, and enhancement of flexibility of output gear ratios, enhancing linearity of step ratios.

While this invention has been described with reference to what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the included exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent claims 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.”

For convenience in explanation and accurate definition in the appended claims, the terms “upper”, “lower”, “internal”, “outer”, “up”, “down”, “upper”, “lower”, “upwards”, “downwards”, “front”, “rear”, “back”, “inside”, “outside”, “inwardly”, “outwardly”, “internal”, “external”, “internal”, “outer”, “forwards”, and “backwards” are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described to explain certain principles of the invention and their practical application, to 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.